Supramolecular nanowires solely composed of cobalt and ruthenium salts enable enhanced stability and activity in light-driven hydrogen evolution

Supramolecular nanowires solely composed of cobalt and ruthenium salts enable enhanced stability and activity in light-driven hydrogen evolution | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Supramolecular nanowires solely composed of cobalt and ruthenium salts enable enhanced stability and activity in light-driven hydrogen evolution Christine Kranz, Eva Oswald, Giada Caniglia, Gaus Anna-Laurine, and 14 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8237178/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Controlling the nanoscale organization of photosensitizer–catalyst (PS–CAT) assemblies into high-surface-area superstructures holds great promise for enhancing photochemical energy conversion yet remains a formidable challenge. We report the nanoconfined deposition of supramolecular photoactive architectures solely composed of cobaloxime-based catalytic salts (CAT) and an imidazophenanthroline-containing ruthenium photosensitizer (PS) salt using via scanning electrochemical cell microscopy (SECCM). This nanoconfinement strategy enables the controlled formation of PS–CAT supramolecular structures ranging from nanospots to nanowires with a diameter of approx. 80–100 nm that catalyze light-driven hydrogen evolution in the absence of covalent linkers. The supramolecular nanowires, formed solely by tuning the nanopipette retraction speed from the surface, exhibit markedly enhanced photoactivity and stability compared to deposited nanospots using the same PS − CAT ratio. Correlative time-of-flight secondary ion mass spectrometry (ToF-SIMS) and nano-infrared (nano-IR) imaging, supported by molecular dynamics simulations, revealed distinct molecular changes of the different nanostructures, highlighting the crucial role of PF₆⁻ − the counterion of the PS − in stabilizing the supramolecular framework. The presented approach allows designing an optimum arrangement of PS − CAT freestanding supramolecular architectures for improved stability and activity without the need for scaffolds and bridging ligands. Physical sciences/Chemistry/Catalysis Physical sciences/Nanoscience and technology/Nanoscale materials/Nanowires Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Introduction Highly efficient solar-to-fuel conversion, inspired by natural photosynthesis, remains among the current challenges in the transition towards sustainable energy production. Using sunlight as the sole energy source to drive carbon dioxide reduction and water splitting has motivated extensive research on semi-conductor-based photocatalytic materials 1 – 4 . In particular, one- and two-dimensional (1D and 2D) semiconductor oxide, nitride and sulfide nanostructures have shown improved light absorption, charge-carrier separation, and higher surface area compared to their bulk counterparts, resulting in enhanced water splitting efficiency 5 – 7 . However, tuning the bandgap of the semiconductor materials to efficiently harvest the full visible-light spectrum and optimal charge migration to harness light-induced charge separation remain a critical bottleneck 8 – 10 . An alternative approach uses light-driven catalysis based on metal-free organic semiconductor materials, such as carbon nitrides 11 , 12 or supramolecular photosensitizer-catalyst (PS − CAT) assemblies 13 , 14 that combine earth-abundant catalysts and chromophores 15 . These systems enable efficient and rational design of molecular-level functionalization, allowing fine-tuning of the optoelectronic properties while reducing environmental impact 16 , 17 . Among hydrogen evolution reaction (HER) catalysts, cobaloximes − molecular cobalt-based complexes − have attracted attention both as biomimetic analogues of alkylcobalamin (vitamine B 12 analog) enzymes 18 , 19 and as efficient model HER catalysts 19 , 20 . They have been integrated into diverse supramolecular assemblies from dyads based on meso -pyridyl boron dipyrromethene (BODIPY) linked to the [Co(dmgH) 2 (py)Cl] cobaloxime catalyst via pyridine (py) bridges 21 to Ru-based PS 22 or [Ru(dnbpy)(tbbpy)₂] 2+ /Co(dmgH)₂ photocatalytic systems (dnbpy = 4,4′-dinitrile-2,2′-bipyridine; tbbpy = 4,4′-di- tert -butyl-2,2′-bipyridine) that remain active under aerobic conditions owing to a nitrile-to-amide transformation which facilitate charge transfer 23 . More recently, fully organic dye–cobaloxime pairs based on ketocoumarins have emerged as metal-free alternatives, reaching turnover numbers (TONs) larger than 3000 in aqueous media 24 . In terms of heterogenous light-driven HER, semiconductor CdSe@CdS nanorods have been modified with a photoprotective polydopamine layer that facilitates the immobilization of cobaloxime catalysts, including the neutral model complex [Co(dmgH) 2 (py)Cl] and charged BPh 2 -bridged cobaloxime derivatives 25 . In addition, Li et al. reported a stable NiO photocathode with an assembled cyclometalated Ru-sensitizer and a HER cobaloxime catalyst ([Co(dmgBF 2 ) 2 (H 2 O) 2 ] + ) for solar hydrogen production 26 . In natural photosystems, photosystem II and I, consisting of very different molecular building blocks, are embedded in highly conserved protein scaffolds which themselves are integrated into the thylakoid membrane resulting in precisely organized architectures. Only this high degree of organization allows for very efficient charge transfer. Mimicking this system, artificial scaffolds with integrated molecular CAT and PS require high stability and nano- to sub-nanometer proximity between PS and CAT to facilitate efficient electron transfer, extend excited-state lifetime, and sufficiently stable oxidation-reduction properties to achieve high catalytic efficiency. Current research focusses on hybrid systems including the integration of CAT and PS in soft functional matrices 27 , 28 , self-assemblies 29 and molecular PS − CAT dyads 30 . Such dyads enable, for example, self-repair mechanisms or mitigation of photodegradation 31 . For instance, supramolecular assemblies have been demonstrated for cobalt-ferrocyanides covalently coordinating PS molecules to form PS − WOC (water oxidation catalyst) dyads 32 . Although the synthesis of molecular components offers high tunability for introducing covalent anchoring functionalities and provides high atom efficiency compared to semiconductors, the preparation of PS–CAT dyads remains inherently complex, since the connecting bridging ligand is responsible for efficient intramolecular electron transfer from PS towards CAT during the lifetime of the excited state, while also maintaining high structural and redox stability of the bridge/spacer 33 . It is therefore highly attractive to integrate molecular PSs and CATs into ordered, high-surface area superstructures (inspired by the protein architectures of photosystems I/II), as this will enable translating the outstanding performance of homogeneous photoactive systems into stable heterogeneous platforms without significant synthetic effort. Tian et al. reported an elegant approach of self-assembled photocatalytic nanofibers based on block copolymers with crystallizable polyferrocenyldimethylsilane (PFS) cores and coronal segments functionalized with either the [Co(dmgH) 2 (py)Cl] catalyst bound to coronal poly(4-vinylpyridine) ligands (PFS-b-Cat) or bound BODIPY as PS (PFS-b-PS) that were co-assembled into low-dispersity, one-dimensional architectures ensuring the required close proximity of CAT and PS 14 . These nanofibers dispersed in solution showed high stability and activity (TON > 7000 over 5 h, TOF > 1400 h - 1 ) for H 2 evolution in MeOH/H 2 O (5%) using triethanolamine (TEOA) as a sacrificial electron donor (SED). Here, we demonstrate that nanoconfinement can direct the formation of solid, photoactive PS–CAT assemblies of high stability, achieving spatial arrangements that promote efficient charge transfer without the need for bridging ligands, polymeric scaffolds or external mediators, thereby providing a simplified yet robust route toward functional photoactive PS–CAT assemblies. Results Immobilization of PS–CAT nanostructures Rather than using covalently bridged PS–CAT assemblies, we report supramolecular PS–CAT nanowires deposited via scanning electrochemical cell microscopy (SECCM). This nanopipette-based technique benefits from nanoconfinement effects for electroless deposition 34 , 35 . In a previous study, we used SECCM to deposit cobaloxime salts as nano- and microspot arrays for accelerated screening experiments with respect to their HER activity using for the localized H 2 measurements scanning electrochemical microscopy (SECM) in combination with Pd-microelectrodes 36 . For the heterogeneous photocatalysis, ascorbic acid (AA) served as SED and [Ru(tbbpy) 2 (RRip)]Cl 3 (ip = 1,3-dialkyl-1H-imidazol[4,5-f][1,10]phenanthrolinium (abbreviated as Ru(mmip)Cl 3 for R = Me) dissolved in the AA solution served as the PS 37,38 in these screening experiments of different cobaloxime salt spots. Ru(mmip)Cl 3 was selected for its high oxygen tolerance and high quantum yield of photoluminescence 39 . Petermann et al. 39 , suggested an intermolecular catalytic cycle in homogeneous solution for the light-driven charge transfer of [Ru(tbbpy) 2 (RR’ip)] 3+ type PSs (including Ru(mmip)Cl 3 ) and Co(dmgH) 2 -based catalysts, using AA as electron donor. It has been postulated that the N-heterocyclic carbene functional group, formed from the imidazolium unit under basic conditions, can coordinate to the catalytic active center, which facilitates the charge transfer 40 . Here, we mix [Ru(tbbpy) 2 (mmip)] 3+ ( Fig. 1 a ) as PF 6 - salt ( Ru(mmip) ) with either [Co(dmgH) 2 (py) 2 ] + BArF - (abbreviated CoBArF , Fig. 1 b) or [Co(dmgH) 2 (py) 2 ] + [Co(dmgBPh 2 ) 2 Cl 2 ] - (abbreviated Co + Co - , Fig. S1a ) 41 , which − among previously tested cobaloxime salts − showed the highest TONs in homogeneous HER and highest activity also in the screening experiments. The mixtures, dissolved in acetonitrile, was filled into the nanopipettes to perform local electroless depositions via SECCM (for experimental details, see Supporting Information and Scheme S1 ). Initial experiments using the well characterized model PS [Ru(bpy)₃](PF 6 ) 2 under identical conditions did not yield reproducible nanostructures and failed to produce well-defined nanowires ( Fig. S2a ). In contrast, Ru(mmip) consistently formed stable and homogeneous nanostructures, which motivated its selection for all subsequent experiments. By varying the PS:CAT molar ratio and the SECCM deposition parameters, we were able to control both the composition and morphology of the resulting supramolecular assemblies. Increasing the relative concentration of the PS in solution promotes extended one-dimensional growth, yielding nanowire whose diameters are defined by the nanopipette orifice (typically approx.100 nm). Nanowires with lengths up to several micrometres were reproducibly fabricated on both conductive and insulating substrates. At lower PS:CAT ratios, or under slow withdrawal conditions (5 µm s - 1 ), the deposition proceeds isotropically, producing hemispherical nanospots instead of nanowire. For a direct comparison of the photocatalytic performance, nanospots were prepared using identical PS:CAT ratios and solvent conditions while only altering the deposition conditions. SECCM (schematically depicted in Fig. 2 a) offers a unique deposition strategy, whereby a nanoscale liquid meniscus defines a confined area enabling spatially controlled immobilization and assembly of molecular precursors directly onto the substrate. The nanoconfinement imposed by the meniscus plays a potentially decisive role in directing the assembly pathway. As already observed for crystallization processes under nanoconfinement conditions 42 , and as also shown here, the restricted geometry and rapid solvent evaporation can stabilize the formation of amorphous molecular aggregates while promoting a favorable arrangement between the charged CAT and PS for effective charge transfer. The positively charged imidazolium unit of Ru(mmip) appears to play a decisive role during the nanoconfined co-deposition, as reproducible nanowire formation was not observed when the model PS, [Ru(bpy) 3 ](PF 6 ) 2 , was used under otherwise identical conditions. This suggests that the specific, non-centrosymmetric/anisotropic charge distribution and intermolecular interactions introduced by the additional N-atoms as well as the C-H-acidic group of the imidazolium moiety may promote a more organized co-assembly with the also positively charged catalyst molecules. As discussed later and supported by molecular dynamics simulations, these interactions likely contribute to the formation of closely associated PS–CAT domains that facilitate efficient photoinduced charge transfer 39 , 41 . Previous studies have shown that in PS − CAT aggregates, the PS is frequently the limiting factor during the photocatalytic process due to its propensity to undergo photodegradation 43 . To sustain photocatalytic turnover and maximize electron transfer efficiency, usually an excess of PS relative to the CAT is used 43 , 44 . For depositing nanostructures, we tested PS:CAT molar ratios of 1:1, 3:1, and 5:1 to identify conditions that favor both controlled nanostructured assembly and photocatalytic performance. A systematic screening of molecular combinations and deposition parameters revealed, that depending on the experimental conditions nanowires or nanospots can be deposited. The formation pathway is predominantly governed by the interplay between solvent polarity, meniscus confinement and solvent evaporation (Fig. 2 b). In an optimized deposition regime, a short meniscus contact (2 s) and a rapid nanopipette withdrawal (150 µm s⁻¹) along with a rapid solvent evaporation rate drives an anisotropic assembly process resulting in the growth of 1D nanowires (Fig. 2 c,d). In contrast, slower evaporation rates (i.e., along with longer contact times and lower withdrawal speeds) lead to an isotropic deposition yielding nanospots. SECCM-based deposition strategies allow using the same concentration ratios while controlling the geometry of the PS − CAT assembly (i.e., nanowire vs. nanospot) at various substrate surfaces by tuning the experimental deposition parameters, yet, maintaining the component ratios. Based on this screening process we could identify that the co-deposition of Ru(mmip) with CoBArF at a 3:1 PS:CAT concentration ratio (dissolved in acetonitrile) yielded reproducible, well-defined nanowires across all tested substrates including gold, ITO, HOPG, silicon, glass polymer films and graphene TEM grids ( Fig. S2 ). The SEM images revealed the formation of vertically oriented, high-aspect-ratio nanowires (Fig. 2 c) that break at the basis of the deposit after wetting the area with a water droplet (Fig. 2 d). Interestingly, the nanowires remained stable in solution in horizontal orientation (Fig. 2 c,d). Other conditions tested either failed to reproducibly form nanowires or resulted in isotropic nanospots with no obvious directional growth ( Fig. S3a ). Similarly, replacing acetonitrile with solvents of lower polarity (e.g., DMF, acetone) resulted in nanospots, despite mantaining the optimal PS − CAT ratio and same experimental conditions. The use of the alternative catalyst ( Co⁺Co⁻, Fig. S4 ) resulted in nanowires, however, with irregular shapes ( Fig. S4a ) and less reproducible deposition behavior ( Fig. S4b ) and nanospots ( Fig. S4d,f ). This behavior underscores that the alignment of charge distribution between PS and CAT appears to favor a unidirectional growth. As shown in previous studies by our team, the SECCM-based deposition of pure cobaloxime catalysts was only feasible on carbonaceous materials such as amino-terminated carbon nanomembrane supports (CNMs) 41 , whereas the co-deposition of nanostructured PS − CAT assemblies is possible on conductive and non-conductive substrates highlighting the stabilizing role of Ru(mmip) during the formation of the co-deposited PS − CAT assemblies. High-resolution AFM and SEM imaging confirmed that the Ru(mmip) − CoBArF nanowires are uniform with lengths up to 2 µm and diameters of 80–100 nm (Fig. 2 c–e). High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) combined with energy dispersive x-ray (EDX) spectroscopy for elemental mapping (Fig. 2 f,g) revealed a homogeneous distribution of Ru, Co, P, and N throughout the nanowires, indicating that the two molecular components co-assemble without phase segregation, i.e., without forming into PS-rich and CAT-rich domains. Moreover, selected-area electron diffraction (SAED) patterns confirmed that both nanowires and nanospots are amorphous ( Fig. S5 ), which is consistent with the expected influence of the nanoconfinement during co-deposition that is expected to suppress the formation of long-range crystallinity while maintaining local molecular ordering 42 . Molecular dynamics simulations To elucidate the interpretation of the supramolecular architecture of the PS–CAT assemblies, we first assessed their crystallinity. SAED patterns showed diffuse features, indicating that the assemblies are amorphous, and attempts to obtain co-crystals from bulk mixtures of the molecular components were likewise unsuccessful. Parallelly, the local organization and intermolecular interactions within the PS − CAT supramolecular structures, can also be explored at the atomistic level using molecular dynamics (MD) simulations. Four representative systems differing in PS:CAT ratio (3:1 and 1:1) and solvent environment (with and without acetonitrile) were chosen to mimic the conditions encountered during deposition by SECCM. The 3:1 system in acetonitrile reproduces the composition within the pipette droplet prior to deposition, and the corresponding system in absence of ACN reflects the confined, post-evaporation environment within the nanostructure. The 1:1 system, in turn, serves as analogues for the less ordered nanospot assemblies. Analysis of the temporal evolution of noncovalent interactions over trajectories up to 1000 ns ( Fig. S6 and S7 ) revealed clear and systematic differences between these environments and identified four dominant noncovalent interactions contributing to the supramolecular organization: salt bridges, π–π stacking, hydrogen bonding, and π–cation interactions (Fig. 3 ). In all simulations, salt bridges involving PF₆⁻ anions emerged as the most persistent and structurally significant interactions. In the 3:1 system containing acetonitrile ( Fig. S6a ), the number of salt bridges increased steadily during the first 500–600 ns before reaching a plateau, consistent with the gradual self-organization of the ionic network interconnecting multiple PS units via their imidazolium groups. Upon removal of the solvent, mimicking the progressive concentration and confinement during nanowire formation, these PF₆⁻-mediated bridges remained stable for the remainder of the trajectory, with only small fluctuations in amplitude Fig. S6b . The resulting configuration, depicted in Fig. 3 a, consists of PF₆⁻ anions anchored between neighboring PSs, which effectively act as ionic crosslinkers that align PS units into directionally correlated domains. This ionic scaffold provides a plausible origin for the cooperative stabilization and anisotropic growth observed experimentally in nanowire architectures, where long-range electrostatic ordering compensates for the absence of covalent bonds between PS and CAT molecules. In contrast, simulations of 1:1 PS:CAT ( Fig. S7 ), mirroring the formation of nanospots, showed a slightly lower number of salt bridges that were less persistent, and the trajectories lacked any indication of a sustained increase in ionic connectivity over time. The limited number of imidazolium sites restricts the probability of multipoint bridges, likely resulting in small, transient aggregates without directional propagation. When PF₆⁻ was removed in silico, the population of salt bridges was reduced, confirming that the counterion is not just a passive presence but critical for mediating intermolecular cohesion. Beyond ionic interactions, MD simulations reveal how the aromatic stacking and π–cationic interactions modulate the local packing within the assemblies. In the absence of solvent, π–π stacking between bipyridine and imidazolium rings from the PS became more pronounced and stable, especially in the 1:1 system ( Fig. S7b ). The π–π interactions exhibited the highest average number of contacts under these conditions, reflecting the propensity of both PS and CAT to cluster through dispersive interactions. However, these contacts tend to form short-range isotropic clusters rather than extended anisotropic architectures, consistent with the formation of spherical or irregular nanospot aggregates rather than elongated nanowires. In contrast, in 3:1 nanowire-like systems, π–π stacking contributed less to the overall stabilization and remained secondary to the PF₆⁻-driven ionic framework. This suggests a hierarchical assembly mechanism, in which the directional networks of salt bridges provide the backbone of the supramolecular scaffold, while the π–π stacking fills the local gaps and adjusts the orientation between the molecules. H bonding, by contrast, was sporadic and short-lived throughout the simulations, occurring mainly within the CAT units and contributing little to the organization of the complex (Fig. 3 b-c). The MD trajectories further reveal that the PS and CAT tend to assemble into “electronically coupled” dyads, stabilized by a framework of short-range ionic and π-driven interactions that eliminate the need for any covalent tether (Fig. 3 c). Two classes of salt bridges dominate the interfacial stabilization. The first mechanism involves a second-sphere Ru···O interaction, in which the cobaloxime nitrosyl/oxime region forms a delocalized hydrogen-bond network (N–O···H···O–N) that orients the CAT relative to the PS. The second, more frequent motif involves the H–bonding between the C2–H proton of the imidazolium ring in the PS − i.e., the acidic hydrogen located between the two ring nitrogens − and the deprotonated oxime oxygen atoms of the CAT, generating persistent imidazolium···O⁻, as highlighted in Fig. 3 c. These interactions create a mixed ionic–coordination interface that locks the two molecular components into close proximity while preserving their individual coordination environments. Superimposed on this ionic framework are π–cation interactions between the pyridyl rings of the PS and the Co(III) center of the CAT, with centroid–metal separations of 4.2–4.6 Å and where the aromatic ring adopts approximately a planar orientation to the CoN₄ coordination plane (right magnified region in Fig. 3 c). Such geometries are ideal for through-space orbital overlap between the aromatic π-system and the partially filled Co d-orbitals, providing a direct pathway for photoinduced electron transfer from the excited Ru(mmip) chromophore to the catalytic center. Importantly, these π–cation contacts appear with comparable frequency in all simulated environments, both in solution and under confined, solvent-free conditions. This fact indicates that the electronic communication between PS and CAT is an intrinsic property of their complementary charge distribution and frontier-orbital alignment, such that no additional chemical linker or external scaffold is required to promote charge transfer. This intrinsic proximity and coupling correlates to the efficient photocatalytic response of the nanowire assemblies and demonstrate that non-covalent ionic and π-interactions can act as self-assembling electronic junctions in molecular heterostructures. Given that nanowires and nanospots are composed of the same molecular building blocks, the emergence of such distinct architectures raises the question which parameters determine whether PF₆⁻ becomes an active part of the supramolecular assembly stability (i.e., nanowire architecture) or remains a passive counterion ( i.e ., nanospot configuration)? The answer may lie in the deposition dynamics occurring during the SECCM experiment. Nanospots are formed via a semi-static meniscus contact, where the solvent evaporates isotropically. This may create a symmetric and radially expanding concentration gradient leading to rapid disordered nucleation and local aggregation 45 . The outward capillary flow drives solutes from the center toward the edge of the contact area (meniscus), a phenomenon known as the coffee-ring effect. As a result, rapid and uncontrolled nucleation of the solute occurs at multiple sites producing many small aggregates rather than an ordered structure 45 . In this context, PF₆⁻ may be unable to integrate into bridging configurations, instead distributing randomly or migrating to the periphery, where it remains more vulnerable to leaching effects. In contrast, nanowires are generated by accelerated pulling of the nanopipette away from the surface after the droplet cell is formed causing directional solvent evaporation 46 which works best for acetonitrile as a low boiling and polar solvent. As the contact line recedes behind the moving meniscus, PS and CAT units are deposited progressively. This apparently creates an anisotropic concentration profile (i.e., a gradient primarily along the direction of motion) rather than a radially symmetric profile, which enables cooperative assembly (i.e., molecules added later align and attach onto the earlier deposited ones) and PF₆⁻ may be subject to spatial constraints that are necessary to connect adjacent PS molecules via salt bridges. The result is a directionally reinforced ionic network that defines the nanowire structure and accounts for its markedly improved stability at photocatalytically relevant illumination conditions. In-situ H evolution To the best of our knowledge, although supramolecular PS–CAT nanofibers have been reported in homogeneous dispersion 14 , immobilized or free-standing assemblies composed solely of PS and HER-CAT components have not yet been explored for light-driven H₂ evolution. Given the dimensions of the Ru(mmip) / CoBArF nanostructures, conventional gas chromatographic or spectroscopic analyses are not suitable. As previously reported, platinum-black (Pt-black)-modified microelectrodes 47 , 48 positioned above the horizontally aligned nanowire or nanospot arrays were successfully used to locally determine the H 2 evolution under illumination using SECM in substrate generation/tip collection (SG/TC) mode 49 (Fig. 4 a). As schematically shown in Fig. 4 b, upon photoexcitation at 470 nm, charge transfer within the PS is expected to proceed from the Ru center toward the imidazolium-functionalized phenanthroline ligand, as reported for Ru(mmip)Cl 3 systems by Petermann et al 39 . This electronic configuration likely facilitates efficient coupling with the nearby CAT in the co-assembled nanowires, enabling photoinduced electron transfer across the PS–CAT interface by an oxidative quenching pathway (see Fig. S8 ). The H 2 evolution – as postulated in the literature for cobaloximes – involves a first single-electron reduction step from Co(III) to Co(II), which proceeds further either through a proton-coupled electron transfer (PCET) (Co(II) to Co(III)–H) or through an additional metal-based single-electron reduction of Co(II) to Co(I) followed by protonation 50 . This step can occur via , for instance, photoinduced electron transfer or via disproportionating charge migration within the structure. Ascorbate serves as solute reducing agent to Ru(mmip) and therefore sustains the catalytic cycle. At pH 4, AA (pK a = 4.2) partially exists in its monoanionic form (ascorbate), a potent and fast hole scavenger with a low oxidation potential (approx. 0.46 V vs. SCE) 51 . H 2 generated in the vicinity of the nanostructure arrays is then electrochemically quantified by the modified microelectrode positioned 20–30 µm above the surface (Fig. 4 b). To validate the measurements, two different microsensors for H 2 detection were employed, Pt-black microelectrodes 47 , which detect H 2 through a dissociative adsorption step (Tafel step) forming chemisorbed hydrogen atoms (H*ₐd), followed by their electrochemical oxidation (Volmer step), ( Fig. S9a ), and Pd-modified microelectrodes 36 , 52 , which relies on H₂ absorption into the Pd lattice and subsequent formation of Pd hydride ( Fig. S9b). Both sensors provided consistent H 2 values ( Fig. S9c ), validating the robustness of the used detection methodology. The chronoamperometric measurements provided a direct and quantitative assessment of H 2 evolution at the nanostructures. The H 2 evolution rates were determined from the recorded currents by applying Faraday’s law taking the illumination time and the determined surface area of the nanowires in the 9 × 9 arrays into account. The resulting current profiles shown in Fig. S10 exhibit a characteristic current onset upon illumination and negligible signals under dark conditions, which indicates that the measured current results from the light-driven catalysis. The arrangement of PS and CAT within the deposited nanostructures and the ratio of PS and CAT obviously plays a critical role for the duration and amount of the H 2 evolution rates. During initial experiments, the PS − CAT ratios were studied using Ru(mmip) / Co + Co - nanospots ( Fig. S11 ). The photocatalytic activity peaked at 0.034 ± 0.004 fmol µm⁻² s⁻¹ for a 3:1 ratio, dropped by 15% to 0.029 ± 0.003 fmol µm⁻² s⁻¹ at 1:1, and was completely suppressed at a ratio of 5:1. This strong dependence on the PS–CAT ratio mirrors the behavior observed in nanoscale light-harvesting assemblies, whereby an optimal sensitizer-to-catalyst ratio maximizes energy- or charge-transfer efficiency by balancing light absorption and exciton delivery to catalytic centers 53 . An optimal ratio ensures the required proximity for productive electron transfer from nearby excited PSs, whereby ( i ) excess of PS leads to detrimental processes like self-quenching and exciton recombination, and ( ii ) excess of catalyst promotes unproductive quenching of excited states or underutilized catalytic sites 53 . In the deposited solid PS − CAT nanostructures, charge transfer is dictated by the nanoscale distances between PS and CAT. At low ratios (1:1), the photon absorption density and exciton generation probability decrease, limiting the rate of photoinduced electron transfer and rendering many catalytic centers underutilized. At high ratios (5:1), the densely packed Ru(mmip) complexes may form a network where a significant fraction of excitations is trapped or relax non-productively, thereby hindering charge separation. Similar high local PS in multinuclear metal complexes or polymer-linked PS leads to triplet-triplet quenching as the dominant photophysical process preventing charge transfer. Moreover, the cationic PS molecules can electrostatically bind to and concentrate around the anionic cobalt catalyst sites, inducing local aggregation which may influence the efficiency of interfacial electron transfer, consistent with colloidal aggregation phenomena reported by Kirchhoff et al. for RuPS–Co systems under homogeneous photochemical conditions 54 . Based on these considerations, a PS:CAT ratio 3:1 was selected. Nanowires composed of Ru(mmip) / CoBArF at a PS:CAT ratio of 3:1 exhibited H 2 evolution rates of 0.33 ± 0.03 fmol µm⁻² s⁻¹, nearly three times higher than nanospot assemblies with identical composition (0.11 ± 0.02 fmol µm⁻² s⁻¹) (Fig. 4 c). In terms of H 2 evolution, we assume that only molecules located at or near the nanostructure surface are catalytically active, as diffusion-limited charge or proton transport likely restricts the participation of buried species. Since the H 2 production rate is normalized to the geometric area, the enhanced activity of nanowires compared to nanospots is not attributed simply to surface exposure but rather to the anisotropic supramolecular organization, which may promote directional electronic coupling along the π-stacked Ru backbones, as supported by MD presented above. Such an arrangement mimics the function of bridged PS − CAT assemblies, where electronic communication between PS and CAT enables more efficient charge separation and transfer to catalytic sites. The robustness of the molecular nanowires was further demonstrated at extended photocatalytic conditions. Long-term illumination tests revealed that the high activity was preserved for at least 12 h, with reaction rates normalized to the exposed surface area remaining essentially constant (0.39 ± 0.04 fmol µm⁻² s⁻¹ after 4 h and 0.41 ± 0.02 fmol µm⁻² s⁻¹ after 12 h, Fig. 4 d). Such sustained performance of supramolecular assemblies is promising for molecular photocatalysts, which typically exhibit declining activity over longer experiments due to photodegradation under continuous irradiation 55 , 56 . For example, Ru(II)polypyridyl PSs are known to be instable in the excited state via population of Jahn-Teller distorted states, or in the oxidized/reduced forms. Very common are ligand dissociation in solution, including ligand loss (photo-substitution) which causes relatively fast deactivation of the photocatalytic system 55 , 57 , 58 . Likewise, several earth-abundant molecular proton-reduction catalysts (such as cobaloxime and polypyridine cobalt complexes) exhibit efficient H₂ generation initially. However, their stability is limited at prolonged irradiation leading to a rapid drop in H₂ evolution due to possible ligand exchange and decomposition 56 , 59 . In the nanowire architecture, the molecular components are effectively anchored within a solid structure which can mitigate the pathways of photodegradation observed in homogenous catalysis 59 . Indeed, since the PS is arranged with the CAT in the solid nanowire, we hypothesize that their ligands are less prone to dissociate, and the physical support and spatial confinement may help maintaining the integrity of the coordination sphere. For example, it has been reported that anchoring an Ir(III) PS on a macroscopic polymer substrate prevented its ligand dissociation, enabling > 730 h of continuous photocatalytic H₂ evolution without deactivation 60 . This demonstrates that a well-designed support can significantly extend the lifetime of a molecular catalyst by suppressing ligand-driven decomposition. We also tested triethanolamine (TEOA, at pH = 10.3) as SED, which is among the most commonly used electron donors in homogeneous and heterogeneous photocatalytic systems 61 . Although TEOA has an oxidation potential of approx. 0.8 V vs. SCE 62 , it exhibits slower electron transfer kinetics, and in aqueous media, only weakly quenches the photoexcited sensitizers 63 . Therefore, it was included for comparison of the H 2 evolution activity of the nanowires. AA (pH = 4) showed higher activity (Fig. 4 e) compared to TEOA (pH = 10.3), which resulted in a 70% lower H 2 evolution activity (Fig. 4 e). This finding is likely due to the stability of the active components at the different pH values. As shown in the SEM images recorded before and after illumination in Fig. S12a,b , the structural integrity of the nanowires is maintained in AA solution, whereas in the basic TEOA solution 61 , 64 , the nanowires are barely visible after illumination ( Fig. S12c,d) . The alkaline medium presumably destabilizes the imidazolium functional group 39 of the PS in the nanowires via deprotonation, decreasing the overall charge of the Ru-PS to 2 + as well as removing the acidic C–H functionality essential for H-bridge-based stabilization, which results in severe morphological degradation. This behavior is consistent with the established base-induced pathways of imidazolium species, which proceed via deprotonation and carbene formation ( Scheme S2 ) 65 – 67 . The disruption of the imidazolium functionality was further confirmed by time-of-flight secondary ion mass spectrometry (ToF-SIMS), which revealed the disappearance of the characteristic imidazolium fragment ( Fig. S13 ). The stability of the PS − CAT nanostructures is probably responsible for the long-term activity. Photostability of the nanostructures A central challenge in heterogeneous photocatalysis lies in maintaining functional stability under photocatalytic conditions. For the supramolecular, solid Ru(mmip) / CoBArF nanostructures, we investigated the stability of both, nanowires and nanospots, under prolonged continuous illumination with respect to the shape and morphology by atomic force microscopy (AFM), and chemical composition via nano-infrared (Nano-IR) imaging, and ToF-SIMS. The experimental approach is supported by the all-atom molecular MD simulations (Fig. 3 ). The AFM topography images shown in Fig. 5 reveal the structural stability of the nanostructures under prolonged photocatalytic conditions. Nanowires and nanospots, both fabricated using a 3:1 PS:CAT ratio of Ru(mmip) and CoBArF , were imaged in air in contact mode before and after irradiation in 0.1 M AA (pH = 4). The comparison reveals a pronounced divergence in structural stability, suggesting different supramolecular organization of nanowires and nanospots despite identical chemical composition. In the case of nanowires (Fig. 5 a), the high-aspect-ratio structures remain clearly unchanged after 24 h of continuous illumination. The height profile (Fig. 5 b) extracted from several nanowires shows a negligible reduction of the nanowire base height from 278 ± 7 nm in the pristine state to 271 ± 8 nm after illumination for 24 h, corresponding to a 1.1% decrease. Whereas, the nanowire body, horizontally lying at the substrate (with an average height of ~ 70 nm), remains essentially unaltered (Fig. 5 b). In strong contrast, nanospots undergo fairly rapid degradation/dissolution under identical illumination conditions (Fig. 5 c). Initially appearing as compact, hemispherical structures with uniform circular profiles and heights of 75 ± 6 nm, the nanospots show signs of dissolution within just 2 h. After 5 h of continuous illumination, the nanospots are barely evident with the height reduced to 4 ± 2 nm (Fig. 5 d). To correlate the structural changes observed by AFM analysis with possible molecular changes and to gain insight into the nature of different activity, nano-IR and ToF-SIMS studies were performed before and after illumination of nanowires and nanospots. In an initial study, the vibrational bands of the PS and the CAT were assigned based on FTIR spectra of the individual components Ru(mmip) and CoBArF as powders ( Fig. S14 ). The vibrational band at 1310 cm⁻¹ was assigned to the C–N⁺ stretching vibration of the imidazolium moiety of Ru(mmip) 68 – 70 , which can serve as a reliable marker for the PS. The P–F stretching vibration at 1415 cm⁻¹ is assigned to the PF₆⁻ counterion 70 , 71 , while the N–O stretching vibration at 1070 cm⁻¹ corresponds to the oxime groups of the cobalt CAT 70 , 72 , 73 . The B–C stretching vibration at 1114 cm⁻¹ indicates the presence of the BArF⁻ counterion 70 , 74 . These specific bands for PS and CAT do not overlap and can be used for the identification of the cations and anions of the supramolecular PS − CAT nanowires. Nano-IR phase maps of pristine and illuminated nanowires at specific frequencies are shown in Fig. 6 a,b. For the pristine nanowires (Fig. 6 a), a clear signal was detected for the C–N + band (1310 cm⁻¹) from the PS, P–F (1415 cm⁻¹) from PF₆⁻, N–O (1070 cm⁻¹) from the CAT, and B–C (1114 cm⁻¹) from BArF⁻ corresponding to the absorption of nanowires. After 2 h of illumination under photocatalytic conditions, the nano-IR phase signal of the Ru(mmip) (1310 cm⁻¹), which correlates with the infrared absorption, remained clearly visible across the nanowire backbone. This indicates that the imidazolium functionality of the PS remains chemically and spatially retained. Similarly, the N–O stretch of the Co-based CAT (1070 cm⁻¹) showed a persistent signal confirming the structural retention of the cobaloxime moiety. The PF₆⁻ signal (1415 cm⁻¹) also remains evident after illumination, whereas the BArF⁻ counterion exhibits a change in its characteristic absorption at 1114 cm⁻¹ (Fig. 6 b). The nano-IR phase maps are markedly different for the nanospots, as shown in the nano-IR phase maps ( Fig. S15) . For the pristine and illuminated nspots ( Fig. S15a ), the nano-IR phase maps corresponding to the absorption of C–N + from the PS, N–O from the CAT, and B–C from BArF⁻ are clearly evident. However, after 1 h of illumination ( Fig. S15b ), the P–F signature at 1415 cm⁻¹ exhibits a changed phase map in which only the inner region of the nanospot, which is the highest part and therefore reflect higher amount of PS-CAT seems to show absorption. This change in signal of the PF₆⁻ characteristic band in the outer rim of the spot indicates possible structural changes, which are confirmed via AFM (Fig. 5 c,d) suggesting that PF₆⁻ may play a pivotal role in maintaining the structural integrity potentially resulting in the stability difference between nanowires and nanospots. The signals corresponding to the Ru-based PS (1310 cm⁻¹) and Co-based CAT (1070 cm⁻¹) show changes in the spot-size, which again correspond well with our AFM data but remain visible after illumination. Therefore, we hypothesize that the degradation of the nanospots is not due to the photodegradation of the functional units but may arise from the loss of the structural counterion (PF 6 − ) of Ru(mmip) . The nano-IR imaging results align well with the ToF-SIMS data (Fig. 6 c-h, and Fig. S16 ), although Co-containing fragments could not be detected, likely due to the low Co concentration and limited ToF-SIMS sensitivity. For the nanowires (Fig. 6 c-h), the C 15 H 13 N 4 + fragment of the Ru(mmip) imidazolium unit remains clearly detectable after 2 h of illumination (Fig. 6 c,d), confirming that the PS core is chemically stable and remains embedded in the supramolecular structure. This fragment corresponds to the imidazolium moiety critical for both light absorption and supramolecular interaction ( e.g ., π–cation and salt bridges), indicating no photo-degradation of the PS under the given photocatalytic conditions. The PF 6 − anion signal (Fig. 6 e,f) persists after illumination, consistent with the nano-IR results for the nanowires. This suggests that PF 6 − is structurally integrated via salt bridges and not simply solvated or surface bound. In contrast, the signal related to the counterion (BArF⁻, C 32 F 24 H 12 B − , Fig. 6 g,h) of the CAT significantly decreases upon illumination. This observation aligns with its weaker electrostatic interaction and larger steric bulk, which likely reduces its incorporation into the supramolecular structure and renders it more susceptible to anion exchange (e.g., with ascorbate anions from solution). Its partial loss, however, does not affect the structural integrity of the nanowires, consistent with the interpretation that the counterion BArF⁻ plays only a passive role in the nanowire architecture. For the nanospots, the C 15 H 13 N 4 + imidazolium fragment ( Fig. S16b,d ) remains detectable after 2 h of illumination, confirming the chemical stability of the PS, independently on the nanostructure. The PF 6 − secondary ion signal ( Fig. S16e,g ) signal notably decreases in intensity after illumination. disappears completely after illumination. The decrease in PF 6 − intensity contrasts with the retention observed in the nanowires and highlights a clear structural vulnerability. It also supports the hypothesis that PF 6 − is not integrated into the supramolecular backbone of the nanospots, yet, electrostatically associated making it highly susceptible to leaching under photocatalytic conditions. These observations are further demonstrated in the MS zoomed spectra recorded at the nanowires and nanospots for each important fragment that are depicted in Fig. S17 and S18 . Conclusions The present study demonstrates that simple molecular components – [Ru(tbbpy)₂(mmip)](PF 6 )₃ as PS and [Co(dmgH)₂(py)₂]⁺BArF⁻ as catalyst – may yield photocatalytic nanostructures with profoundly different performance and stability. Despite their identical molecular composition, nanowires and nanospots exhibit significantly different structural and functional resilience due to their distinct supramolecular architectures, which apparently originate from differences in deposition dynamics. For nanowires, the PF₆⁻ ion forms stabilizing salt bridges between photoactive units reinforced by directional solvent evaporation during SECCM-based deposition. In contrast, nanospots lack this ordered ionic framework leading to PF₆⁻ loss and dissolution upon illumination under photocatalytically relevant conditions. The nanowire architecture not only preserved its structural integrity but also showed increased photocatalytic performance with an approx. three-times higher H 2 evolution rate when compared with nanospots of the same composition ratio. This enhancement may arise from the anisotropic topology of the nanowires, which maximizes the exposure of the catalytic sites and supports directional charge transport along π-stacked Ru backbones while minimizing charge recombination. These findings suggest the pivotal role of counterion organization in dictating the stability of molecular photocatalysts in heterogeneous systems. The lack of reproducible formation of stable nanostructures with twofold positively charged standard ruthenium dye [Ru(bpy) 3 ](PF 6 ) 2 containing just two PF 6 − anions per ruthenium unit, while maintaining all other parameters, highlights the importance of these anions. The combination of operando activity studies via SECM and ex situ analysis using AFM, mass spectrometry, ToF-SIMS and nano-IR imaging augmented by associated MD simulations demonstrated that subtle shifts in supramolecular architecture governed by both molecular design and processing conditions may significantly affect the operational robustness of the system. These findings highlight the necessity of considering counterion behavior and deposition dynamics during rational design of next-generation photoactive nanostructures. From a very general point of view, the presented findings offer a highly attractive perspective on future developments in artificial photosynthesis. Photocatalytically active supramolecular structures consisting of a PS, a bridging ligand (BL) and a CAT are often employed (see Fig. S19a ) and allow for an in principle facile optimization of the catalytic performance by targeted adjustment of molecular structures. This promise has so far been hampered by the significant synthetic effort which needed to be placed in the BL. The herein presented supramolecular nanostructures have the potential to fulfill this promise as they are constructed from simple molecular building blocks ensuring sufficient interaction between PS and CAT without the need of a BL (see Fig. S19b ) while at the same time possessing high stability and hour-long photocatalytic activity without decomposition. Electroless deposition of this architecture on several substrates has furthermore exemplified its technological appeal and may be transferred to other nanoconfinement scenarios. Finally, our findings provide a blueprint for engineering self-assembly of molecular catalysts and sensitizers into electronically coupled and mechanically resilient architectures without the need of covalent linkers. By tuning deposition dynamics, solvent environment, and counterion identity – as demonstrated here by nanoconfinement – opens a pathway to long-range ionic networks that bridge molecular photochemistry with solid-state functionality. Methods Chemical Reagents Commercially available reagents for syntheses were purchased from Sigma Aldrich, Alfa Aesar, Acros Organics, or TCI and were used without further purification. All aqueous solutions were freshly prepared with deionized water (18.0 MΩ cm, Elga Labwater; VWR Deutschland, Germany). Acetonitrile (≥ 99.9%), L-(+)-ascorbic acid (AA) (99.0-100.5%), and sodium hydroxide (NaOH) were purchased from VWR Chemicals (Darmstadt, Germany). Potassium tetrachloropalladate (II) (K 2 PdCl 4 ) was purchased from Alfa Aesar (Thermo Fisher GmbH, Kandel, Germany). Hydrogen hexachloroplatinate (H 2 PtCl 6 ), lead (II) nitrate (Pb(NO 3 ) 2 ), triethanolamine (TEOA), and sodium sulfate (Na 2 SO 4 ) were purchased from Merck (Darmstadt, Germany). Synthesis of CAT and PS [Co(dmgH) 2 (py) 2 ] + BArF − ( CoBArF ) and [Ru(tbbpy) 2 (mmip)](PF 6 ) 3 ( Ru(mmip) )were synthesized as described previously 41 , 75 . For CoBArF , first, a cobaloxime-based double complex with formula [Co(dmgH) 2 (py) 2 ] + [Co(dmgBPh 2 ) 2 Cl 2 ] − ( Co + Co − ) was prepared by dissolving [Co(dmgH) 2 (py)Cl] (200 mg) in anhydrous acetonitrile (9.0 mL) and adding triphenylborane (242 mg). The mixture was stirred in anhydrous acetonitrile (9.0 mL) at room temperature for 5 h and the resulting precipitate was collected and washed with diethyl ether, ethanol, and water, to yield pure Co + Co − as a brown solid (220 mg, 77%). The salt (20 mg) was suspended in chloroform (6 mL) and 22 mg NaBArF was added. The reaction mixture was stirred for 20 min and quenched with 7 mL of water, with the formation of two phases. The organic phase was collected, washed twice with water (2 x 10 mL), and dried over MgSO 4 . The resulting beige/ orange solid was washed with cold diethyl ether, yielding 9 mg of pure CoBArF (39%). Co-deposition of PS and CAT microstructures via SECCM The SECCM depositions were carried out by a lab-built SECCM setup, as previously described 41 . The setup is controlled using LabVIEW 2016 software (National Instruments, Austin, USA), assisted by an FPGA card (PCIe 7851, National Instruments, Austin, USA). LabVIEW software is part of the publicly available Warwick Electrochemical Scanning Probe Microscopy (WEC-SPM) software 76 . Current measurements were performed with a low-noise current preamplifier (SR570, Stanford Research Systems, USA). Nanopipettes with orifices of 100 nm or 500 nm (measured accurately by SEM) were made from quartz theta capillaries (1.2 mm OD, 0.9 mm ID, Sutter Instruments, Novato, USA) using a laser pipette puller (P-2000, Sutter Instruments, Novato, USA). The nanopipettes were back-filled with Ru(mmip) PS and CoBArF catalyst solution in acetonitrile and different PS:CAT ratios. The following concentration ratios were used: PS:CAT 1:1 (0.4 mM PS, 0.4 mM CAT), 3:1 (1.2 mM PS, 0.4 mM CAT), and 5:1 (2 mM PS, 0.4 mM CAT). Ag wires were inserted in the back opening of each barrel serving as quasi-reference counter electrodes (QRCEs). The nanopipette was mounted on a z -piezo positioner (P-753.2CD, Physics Instruments, Karlsruhe, Germany), and perpendicular to the substrate, which was mounted on an x-y piezo table (P-541.2CD, Physics Instruments, Karlsruhe, Germany). A micro-positioner (MTS25-Z8, Thorlabs GmbH, Bergkirchen, Germany) assisted by a digital camera (PL-B776U, PixeLink, Ottawa, Canada) and a cold light source (MI-150, Edmund Optics, Mainz, Germany), was used for the manual positioning of the pipette at a distance of approx. 20 µm above the substrate. An automated software-controlled approach was performed by applying a potential of + 25 mV between the two QRCEs and moving the pipette with a rate of 200 nm s − 1 until the droplet contact was formed, indicated by a change in the DC ion current measured between the two QRCEs. To form the nanospots, the nanopipette was then kept in contact with the substrate for 5 s to favor the co-deposition of the photocatalytic components. After this time, the nanopipette was retracted with a speed equal to 5 µm s − 1 and moved automatically to the next deposition site via hopping mode SECCM. To form the nanowires, the nanopipette was kept in contact with the substrate for 2 s and withdrawn with a speed of 150 µm s − 1 . Preparation of H 2 amperometric microsensors and in-situ H 2 measurements via SECM Two types of H 2 microsensors were used for the quantification of H 2 evolution at the PS − CAT nanostructures: a Pd-modified Au-Ni microelectrode 36 and a platinum-black (Pt-black)-modified microelectrode 47 , 48 . The 25-µm-diameter disk-shaped Au-Ni and Pt microelectrodes were fabricated by melting the Au-Ni or Pt microwire (Goodfellow, Bad Nauheim, Germany) into borosilicate glass (glass capillaries (Hilgenberg, Malsfeld, Germany) following well-established procedures 77 . The preparation of the Pd-modified Au-Ni microsensor has been described elsewhere 36 . Briefly, a three-electrode setup with the Au-Ni microelectrode as a working electrode, an Ag/AgCl/ KCl, 3M reference electrode, and a Pt counter electrode were used. In the first step, the Au-Ni microelectrode was etched in 0.1 mol L − 1 KCl by cyclic voltammetry (15 cycles in the potential range of + 0.20 V to + 0.90 V and scan rate of 0.20 V s − 1 ). In a second step, Pd was electrochemically deposited onto the etched Au-Ni microelectrode in 20 mmol L − 1 K 2 PdCl 4 using pulsed deposition (150 pulse cycles with a potential pulse sequence of + 0.35 V/0.5 s; +0.60 V/ 0.5 s). The Pt microelectrode was modified by electro-platinization, i.e., by depositing Pt-black onto the bare Pt microelectrode 78 . H 2 PtCl 6 (30.6 mmol L − 1 in PBS) is reduced in the presence of Pb(NO 3 ) 2 (0.65 mmol L − 1 ) at a constant potential of -0.06 V for 40 s. The H 2 calibration procedures of both sensors, as previously reported 47 , was performed in 0.1 mol L − 1 ascorbic acid (pH 4) in a closed glass chamber. Different concentrations of H 2 were obtained by mixing N 2 with pure H 2 gas in varying proportions, using a mass flow controller (Bronkhorst GmbH, Kamen, Germany). The detection and quantification of H 2 was obtained via chronoamperometry, by applying a potential equal to -0.6 V vs. Ag/AgCl (Pd sensor) or -0.05 V vs. Ag/AgCl (Pt-black sensor). The HER measurements were performed either using a custom-build SECM setup or a SECM instrument from Sensolytics GmbH (Bochum, Germany), equipped with, respectively, a Palmsens4 potentiostat (Palmsens, Houten, Netherlands) or an Autolab/PGSTAT302N bi-potentiostat (Metrohm, Germany). All SECM studies were performed in a three-electrode setup with the microelectrode serving as the working electrode, an Ag/AgCl quasi-reference electrode, and a Pt wire as the counter electrode. To evaluate the photocatalytic activity of the PS − CAT systems, the H 2 sensor was positioned above the PS − CAT array and all measurements were performed in a 0.1 mol L − 1 ascorbic acid argon-purged solution (pH 4) and at a tip-surface distance of approx. 20 − 30 µm. To determine the tip-surface distance, the sample was first immersed in an aerated ascorbic acid solution and oxygen was used as the electroactive species to perform approach curves in SECM feedback mode. Once the tip-surface distance was determined, the solution was changed to an O 2 -free solution, and a potential of -0.60 V (Pd-modified sensor) or -0.05 V (Pt-black sensor) was applied. All experiments were performed under an argon atmosphere. A 400 µm optical fiber (MT-28L01, Thorlabs GmbH, Bergkirchen, Germany) connected to a 21.8 mW blue LED (M470F3, Thorlabs GmbH) was used for illumination. AFM, SEM, and STEM-EDX measurements AFM measurements were performed using a 5500 AFM/SPM microscope (Keysight Technologies, AZ, USA). AFM contact mode images were recorded in air using silicon nitride probes (ORC-8, Bruker AFM probes, CA, USA; nominal spring constant of 0.1 N m − 1 ) and a scan speed of 0.50 ln s − 1 . PicoView 1.20 and MoutainSPIP® v. 9 (Digital Surf, France) software were used to perform, respectively, the AFM experiments and the data processing. AFM measurements were recorded at pristine samples and samples treated under photocatalytic conditions to investigate the stability of the nanowires/nanospots structures. For the treatment under photocatalytic conditions, the samples were immersed in a 0.1 M AA solution (pH 4 adjusted with concentrated NaOH) previously purged with argon and illuminated for up to 24 h with a blue LED (λ = 470 nm). During the illumination, the samples were kept under an argon atmosphere. After illumination, the substrates were washed three times with ultrapure water, air-dried, and imaged with AFM. SEM images of the nanostructures were obtained with a Helios Nanolab 600 FIB/SEM (ThermoFisher, FEI, Eindhoven, Netherlands) operating at 1–3 kV and beam currents of 86 pA by using the in-lens detector (immersion mode) of the instrument. Data processing was done using the Fiji software package (ImageJ 1.53t). The elemental composition and elemental mapping of the immobilized nanostructured were done using a ThermoFisher Talos F200X transmission electron microscope (TEM) operated in scanning mode (STEM) for simultaneous acquisition of high-angle annular dark field (HAADF) images and spatially-resolved energy dispersive x-ray (EDX) spectra. Those spectra were background-subtracted and used to generate elemental maps. ToF-SIMS studies Time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses were conducted using a ToF-SIMS M6 Plus instrument (IONTOF GmbH, Münster, Germany) equipped with a Bi-cluster LMIG primary ion source. Spectra and secondary ion images were acquired in both positive and negative ion polarities under “delayed extraction” conditions. A pulsed Bi 3 ++ primary ion beam was operated at 60 keV with a cycle time of 100 µs and a beam defining aperture of 110 µm. The primary ion current, measured prior to analysis using an internal Faraday cup, was approximately 0.06 pA. Each dataset was collected over a surface area of 25 × 25 µm² with an image resolution of 512 × 512 pixels. The achieved mass resolution at m / z 29 was about 4500 m /Δ m (FWHM). Data acquisition was terminated once a total ion fluence of ~ 8 × 10¹² ions/cm² had been reached. Positive ion spectra were mass-calibrated using the following reference peaks: C 2 H 5 + , C 3 H 7 + , C 4 H 9 + , Au + , Au 2 + , Au 3 + . Negative ion spectra were calibrated using the ions C 2 − , Cl − , C 3 − , C 4 − , Au − , Au 3 − . Nano-IR imaging Nano-IR imaging was performed using a NeaSNOM (Attocube, Germany) instrument, in which the AFM operates in tapping mode with an in-house 60 nm platinum-coated AFM tip (Arrow NCR, NanoWorld) oscillating at an amplitude of 75 nm at the detected mechanical resonance of ~ 236 kHz. Nano-IR imaging utilized a mid-infrared quantum cascade laser (Daylight Solutions, USA) with an approximate power of 1.5–2.2 mW, and a Michelson interferometer analyzed the tip-scattered light using a liquid nitrogen cooled mercury cadmium telluride detector. Pseudoheterodyne detection provides background-free and simultaneous detection of optical amplitude and phase signals, with the phase signal corresponding to the IR absorption. The images are acquired with 256 x 256 px grid and an integration time of 3 ms/px. The images at 3rd order demodulation are presented, after background and scar correction of the raw data. Phase unwrapped for some of the maps. The preprocessing is performed using Gwyddion 2.61 79 and MoutainSPIP® v. 9 (Digital Surf, France). Molecular dynamics simulations All molecular structures were initially optimized deploying DFT in the Jaguar optimization tool (Schrödinger Suite) 80 , 81 . The CAT and PF6 complex were optimized using B3LYP-D3/6-31G(d,p). The PS and BArF complex were optimized using the B3LYP-D3/def2-SVP level of theory, to have an appropriate balance between accuracy and computational efficiency. To model molecular aggregation and self-assembly behavior, disordered multicomponent systems were constructed with varying stoichiometric ratios. For the 1:1 system, the simulation box contained 60 CAT, 60 BARF, 60 PS molecules, 180 PF₆ counterions. For the 1:3 system, 20 CAT, 20 BARF, 60 PS molecules, 180 PF₆ counterions were included. To simulate realistic solvent conditions, each system was solvated with 6000 acetonitrile (ACN) molecules. All systems were equilibrated prior to production runs. Molecular dynamics (MD) simulations were performed using Desmond module (Schrödinger Suite) under periodic boundary conditions. Each system was equilibrated in the NVT ensemble at 300 K, followed by a production simulation in the NPT ensemble at 300 K and 1.01325 bar. A 2-fs integration time step was employed, and trajectories were recorded every 2000ps. Each simulation was run for 1000 ns (1 µs) to ensure adequate sampling of molecular motion, aggregation, and nano structuring behavior. Trajectories were subsequently analyzed to evaluate intermolecular interactions, aggregation patterns, and solvent-mediated assembly. Data Availability The data supporting the findings of this study are available within this Article and its Supplementary Information. Data are available from the corresponding authors upon request. Declarations Acknowledgments The project is funded by the Deutsche Forschungsgemeinschaft (DFG – German Research Foundation) – project number 364549901 – TRR 234, subprojects A4, C2, C4, B7 and Z2. The authors acknowledge the FIBCenter UUlm and Dr. Gregor Neusser (Institute of Analytical and Bioanalytical Chemistry, Ulm University) for the FIB-SEM measurements. Savelii Filipkov (Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena) is acknowledged for the support during Nano-IR measurements. The authors also acknowledge support by the state of Baden-Württemberg through bwHPC and the German Research Foundation (DFG) through Grant no INST 40/575-1 FUGG (JUSTUS 2 cluster) as well as INST 162/544-1 FUGG. VD, WW & TS also acknowledge funding by the DFG (SFB NOA Nr 398816777, C2) and the Bundesministerium für Forschung, Technologie und Raunfahrt (BMFTR) funding program Photonics Research Germany („LPI-BT1“, FKZ: 13N15466) and integrated into the Leibniz Center for Photonics in Infection Research (LPI). The LPI initiated by Leibniz-IPHT, Leibniz-HKI, UKJ and FSU Jena is part of the BMBF national roadmap for research infrastructures. Author contributions Eva Oswald data curation, SECCM depositions and writing of the draft. Giada Caniglia: Conceptualization, data curation, writing, review and editing. Anna-Laurine Gaus, Martin Lämmle and Alexander K. Mengele: Conceptualization and synthesis of catalysts and photosensitizers. Soumya Rajpal: molecular dynamics simulation and data curation. Giuseppe Ragusano and Marcus Rohnke: ToF-SIMS studies and data curation. Tanveer Shaik, Wei Wang: Nano-IR studies and data curation. Robert Leiter, Johannes Biskupek and Ute Kaiser: HAADF-STEM, EDX, SADPs measurements and data curation. Max von Delius, Volker Deckert, Sven Rau, Volker Deckert and Boris Mizaikoff: Supervision, funding acquisition, review, and editing. Christine Kranz: Conceptualization, supervision, project administration, funding acquisition, writing, review, and editing. Competing interests The authors declare no competing interests. Additional information Supplementary information. The online version contains supplementary material available at https://doi.org/... References Hansora, D.; Mehrotra, R.; Noh, E.; Yoo, J. W.; Kim, M.; Byun, W. J.; Park, J.; Jang, J.-W.; Seok, S. Il; Lee, J. S. Scalable and Durable Module-Sized Artificial Leaf with a Solar-to-Hydrogen Efficiency over 10%. Nat Commun 2025 , 16 (1), 4186. https://doi.org/10.1038/s41467-025-59597-2. Kumar, A.; Hasija, V.; Sudhaik, A.; Raizada, P.; Van Le, Q.; Singh, P.; Pham, T.-H.; Kim, T.; Ghotekar, S.; Nguyen, V.-H. 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During the process, the nanopipette approaches to the gold surface until forming a meniscus; after a rest time, the nanopipette is withdrawn at a rate of 150 µm s⁻¹ and the evaporation of ACN favors the formation of the nanowire. \u003cstrong\u003eb\u003c/strong\u003e Schematic illustration of the formation of the nanowires: molecules nucleate and align into nanowires upon contact with the substrate from their initial state of random dispersion when in the solvent observed in atomistic molecular dynamics simulations. \u003cstrong\u003ec-d\u003c/strong\u003eSEM images (52° inclination) of the vertically standing nanowires (\u003cstrong\u003ec\u003c/strong\u003e) and the horizontally arranged nanowires after adding a water droplet (\u003cstrong\u003ed\u003c/strong\u003e). \u003cstrong\u003ee\u003c/strong\u003e High-resolution AFM image recorded in air of a single nanowire. \u003cstrong\u003ef\u003c/strong\u003e-\u003cstrong\u003eg\u003c/strong\u003e HAADF-STEM image (\u003cstrong\u003ef\u003c/strong\u003e) and corresponding color-coded EDX elemental maps (\u003cstrong\u003eg\u003c/strong\u003e) for Co, Ru, P and N distribution of \u003cstrong\u003eRu(mmip)\u003c/strong\u003e/\u003cstrong\u003eCoBArF\u003c/strong\u003e nanowire. The PS:CAT ratio of all nanowires is equal to 3:1.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8237178/v1/24f5cfd2e1f91e24cc115576.png"},{"id":99187113,"identity":"1ccfff94-7d54-469d-bb19-94d709bb8d44","added_by":"auto","created_at":"2025-12-30 00:09:12","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":290580,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMolecular dynamics simulations of key interactions in the nanostructure systems.\u003c/strong\u003e \u003cstrong\u003ea\u003c/strong\u003eSalt bridges (magenta dashed lines) between Ru complex and PF₆⁻counterions establish the supramolecular backbone of the nanostructures. The Ru complex exhibits intramolecular π–π stacking interactions (cyan dashed lines) supporting structural organization. \u003cstrong\u003eb\u003c/strong\u003eThe catalytic unit (Co complex)primarily engages in π–cation (green dashed lines) and π–π stacking interactions with the BArF⁻counterion, while hydrogen bonds (yellow dashed lines) remain confined within the Co complex itself. \u003cstrong\u003ec\u003c/strong\u003e Representation of the co-assembled Ru-based PS (Ru centers in teal) and Co-based CAT (Co centers in blue), illustrating dominant non-covalent interactions identified in MD simulations. A π–cation interaction between the aromatic moieties of PS and the metallic center of the CAT is observed at a distance of approx. 4.5 Å (green dashed line), while a hydrogen bond between hydroxyl groups of the cobaloxime core forms at approx. 2.8 Å (yellow dashed line). The magnified regions emphasize representative salt bridge contact between the ruthenium center (left) and the imidazolium moiety (right) with Co-CAT units. These proximities are indicative of spatial arrangements that favor both, supramolecular stabilization and potential electronic coupling, thus promoting the photoinduced charge transfer essential for HER.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8237178/v1/b8a10daf2f3be26f58ba03be.png"},{"id":99187120,"identity":"cce759e7-10be-4be8-8f58-48b7265ecff6","added_by":"auto","created_at":"2025-12-30 00:09:12","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":278643,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eH\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e photoproduction reaction rate from the nanostructures using SECM\u003c/strong\u003e. \u003cstrong\u003ea\u003c/strong\u003e Schematics of the H\u003csub\u003e2\u003c/sub\u003e quantification in SECM generation/collection mode using a H\u003csub\u003e2\u003c/sub\u003e-microsensor serving as the working electrode, Ag/AgCl as quasi-reference electrode and a Pt wire as counter electrode. \u003cstrong\u003eb\u003c/strong\u003e Schematic illustration of the possible electron transfer during the light-driven H₂ production and its subsequent detection \u003cem\u003evia\u003c/em\u003e SECM. \u003cstrong\u003ec\u003c/strong\u003e Highest H\u003csub\u003e2\u003c/sub\u003e evolution reaction rates obtained at \u003cstrong\u003eRu(mmip)\u003c/strong\u003e/\u003cstrong\u003eCoBArF\u003c/strong\u003e nanospots and nanowires at a PS:CAT ratio equal to 3:1 in presence of AA (pH = 4) serving as sacrificial electron donor. \u003cstrong\u003ed\u003c/strong\u003e H\u003csub\u003e2\u003c/sub\u003e evolution reaction rate obtained at \u003cstrong\u003eRu(mmip)\u003c/strong\u003e/\u003cstrong\u003eCoBArF\u003c/strong\u003e nanowires (PS:CAT ratio of 3:1) after 4 h and 12 h of illumination. The operando measurements for 12 h under illumination have been recorded in three successive experiments of 4 h to avoid interference from solvent evaporation. \u003cstrong\u003ee\u003c/strong\u003e Comparison between the H\u003csub\u003e2\u003c/sub\u003e evolution reaction rate obtained at \u003cstrong\u003eRu(mmip)\u003c/strong\u003e/\u003cstrong\u003eCoBArF\u003c/strong\u003e nanowires (PS:CAT ratio of 3:1) using 0.1 M AA (pH = 4) and 10 vol% TEOA (pH = 10.3) as a SED after 3\u0026nbsp;h of illumination. All error bars reflect three different samples.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8237178/v1/85681e55e838de72ce7fa950.png"},{"id":99315832,"identity":"63b80f99-10ae-49ad-899a-0f44099ca411","added_by":"auto","created_at":"2025-12-31 16:27:23","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":157719,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStability studies of the nanostructures \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003evia\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e AFM\u003c/strong\u003e. \u003cstrong\u003ea\u003c/strong\u003eAFM topography images recorded in air in contact mode of \u003cstrong\u003eRu(mmip)\u003c/strong\u003e/\u003cstrong\u003eCoBArF\u003c/strong\u003enanowires with PS:CAT ratio of 3:1 before and after 24 h under illumination. \u003cstrong\u003eb\u003c/strong\u003eChange in height observed on the \u003cstrong\u003eRu(mmip)\u003c/strong\u003e/\u003cstrong\u003eCoBArF\u003c/strong\u003e nanowires after different exposure to photocatalytic conditions. The bar graph compares the average height measured at the nanowire body and nanowire base after 0 h (blue), 3 h (red), and 24 h (green) of illumination. The inset shows a representative AFM image highlighting the regions analyzed, body (yellow line) and base (magenta line). Error bars represent the standard deviation from measurements of at least nine different nanowires. All error bars reflect the measurement of at least nine different nanospots. \u003cstrong\u003ec\u003c/strong\u003e Exemplary AFM topography images recorded in air in contact mode of a \u003cstrong\u003eRu(mmip)\u003c/strong\u003e/\u003cstrong\u003eCoBArF\u003c/strong\u003enanospot with PS:CAT ratio of 3:1 before and after different illumination duration. \u003cstrong\u003ed\u003c/strong\u003e Change in height observed on \u003cstrong\u003eRu(mmip)\u003c/strong\u003e/\u003cstrong\u003eCoBArF\u003c/strong\u003e nanospots over time under photocatalytic conditions. All error bars reflect the measurement of at least nine different nanospots.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-8237178/v1/56175875d52b1b17f58946af.png"},{"id":99187128,"identity":"05f3bc71-a9b3-4282-85be-c55102c31aef","added_by":"auto","created_at":"2025-12-30 00:09:12","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":632225,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eNano-IR and ToF-SIMS measurements on the (photo)stability of the nanowires\u003c/strong\u003e. \u003cstrong\u003ea-b\u003c/strong\u003e Nano-IR images before (\u003cstrong\u003ea\u003c/strong\u003e) and after (\u003cstrong\u003eb\u003c/strong\u003e) 2h of illumination, at the 1310, 1415, 1070 and 1114 cm\u003csup\u003e-1\u003c/sup\u003e absorptions to target the presence of, the \u003cstrong\u003eRu(mmip)\u003c/strong\u003e complex (C–N\u003csup\u003e+\u003c/sup\u003e stretch), the \u003cstrong\u003ePF\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e6\u003c/strong\u003e\u003c/sub\u003e\u003csup\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/sup\u003e counterion (P–F stretch), the \u003cstrong\u003ecobaloxime\u003c/strong\u003e compound (N–O stretch), and the \u003cstrong\u003eBArF\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/sup\u003e counterion (B–C stretch), respectively. Color bars of the nano-IR maps correspond to the absorption. \u003cstrong\u003ec-d\u003c/strong\u003e ToF-SIMS positive ion mode images of nanowire arrays before (\u003cstrong\u003ec\u003c/strong\u003e) and after 2 h of illumination in ascorbic acid (\u003cstrong\u003ed\u003c/strong\u003e). The major fragment detected corresponds to the basal ligand with the imidazolium. \u003cstrong\u003ee-h\u003c/strong\u003e Negative ion mode images of nanowire arrays before (\u003cstrong\u003ee, g\u003c/strong\u003e) and after 2 h of illumination (\u003cstrong\u003ef, h\u003c/strong\u003e). The major fragments detected correspond to the \u003cstrong\u003ePF\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e6\u003c/strong\u003e\u003c/sub\u003e\u003csup\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/sup\u003e\u003csup\u003e \u003c/sup\u003ecounterion (\u003cstrong\u003ee, f\u003c/strong\u003e) and the \u003cstrong\u003eBArF\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/sup\u003e counterion (\u003cstrong\u003eg, h\u003c/strong\u003e).\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-8237178/v1/31b9447fa55c90bff10feb38.png"},{"id":99323769,"identity":"8af3bad2-365d-44f6-871e-dc1a1e5761dd","added_by":"auto","created_at":"2025-12-31 16:46:11","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3554686,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8237178/v1/82de86be-6eb0-4889-8816-80511b11bb02.pdf"},{"id":99316205,"identity":"9d61580a-d406-478c-91dd-a654779af7bd","added_by":"auto","created_at":"2025-12-31 16:27:53","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":4536584,"visible":true,"origin":"","legend":"Supporting information on supramolecular nanowires","description":"","filename":"OswaldetalSupportingInformation25112025.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8237178/v1/ab2e8a6892ce93c5bca70ebf.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Supramolecular nanowires solely composed of cobalt and ruthenium salts enable enhanced stability and activity in light-driven hydrogen evolution","fulltext":[{"header":"Introduction","content":"\u003cp\u003eHighly efficient solar-to-fuel conversion, inspired by natural photosynthesis, remains among the current challenges in the transition towards sustainable energy production. Using sunlight as the sole energy source to drive carbon dioxide reduction and water splitting has motivated extensive research on semi-conductor-based photocatalytic materials\u003csup\u003e\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. In particular, one- and two-dimensional (1D and 2D) semiconductor oxide, nitride and sulfide nanostructures have shown improved light absorption, charge-carrier separation, and higher surface area compared to their bulk counterparts, resulting in enhanced water splitting efficiency\u003csup\u003e\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. However, tuning the bandgap of the semiconductor materials to efficiently harvest the full visible-light spectrum and optimal charge migration to harness light-induced charge separation remain a critical bottleneck\u003csup\u003e\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. An alternative approach uses light-driven catalysis based on metal-free organic semiconductor materials, such as carbon nitrides\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e or supramolecular photosensitizer-catalyst (PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT) assemblies\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e,\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e that combine earth-abundant catalysts and chromophores\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. These systems enable efficient and rational design of molecular-level functionalization, allowing fine-tuning of the optoelectronic properties while reducing environmental impact\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. Among hydrogen evolution reaction (HER) catalysts, cobaloximes\u0026thinsp;\u0026minus;\u0026thinsp;molecular cobalt-based complexes\u0026thinsp;\u0026minus;\u0026thinsp;have attracted attention both as biomimetic analogues of alkylcobalamin (vitamine B\u003csub\u003e12\u003c/sub\u003e analog) enzymes\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e and as efficient model HER catalysts\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e,\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. They have been integrated into diverse supramolecular assemblies from dyads based on \u003cem\u003emeso\u003c/em\u003e-pyridyl boron dipyrromethene (BODIPY) linked to the [Co(dmgH)\u003csub\u003e2\u003c/sub\u003e(py)Cl] cobaloxime catalyst \u003cem\u003evia\u003c/em\u003e pyridine (py) bridges\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e to Ru-based PS\u003csup\u003e22\u003c/sup\u003e or [Ru(dnbpy)(tbbpy)₂]\u003csup\u003e2+\u003c/sup\u003e/Co(dmgH)₂ photocatalytic systems (dnbpy\u0026thinsp;=\u0026thinsp;4,4\u0026prime;-dinitrile-2,2\u0026prime;-bipyridine; tbbpy\u0026thinsp;=\u0026thinsp;4,4\u0026prime;-di-\u003cem\u003etert\u003c/em\u003e-butyl-2,2\u0026prime;-bipyridine) that remain active under aerobic conditions owing to a nitrile-to-amide transformation which facilitate charge transfer\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. More recently, fully organic dye\u0026ndash;cobaloxime pairs based on ketocoumarins have emerged as metal-free alternatives, reaching turnover numbers (TONs) larger than 3000 in aqueous media\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e. In terms of heterogenous light-driven HER, semiconductor CdSe@CdS nanorods have been modified with a photoprotective polydopamine layer that facilitates the immobilization of cobaloxime catalysts, including the neutral model complex [Co(dmgH)\u003csub\u003e2\u003c/sub\u003e(py)Cl] and charged BPh\u003csub\u003e2\u003c/sub\u003e-bridged cobaloxime derivatives\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. In addition, Li et al. reported a stable NiO photocathode with an assembled cyclometalated Ru-sensitizer and a HER cobaloxime catalyst ([Co(dmgBF\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e(H\u003csub\u003e2\u003c/sub\u003eO)\u003csub\u003e2\u003c/sub\u003e]\u003csup\u003e+\u003c/sup\u003e) for solar hydrogen production\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIn natural photosystems, photosystem II and I, consisting of very different molecular building blocks, are embedded in highly conserved protein scaffolds which themselves are integrated into the thylakoid membrane resulting in precisely organized architectures. Only this high degree of organization allows for very efficient charge transfer. Mimicking this system, artificial scaffolds with integrated molecular CAT and PS require high stability and nano- to sub-nanometer proximity between PS and CAT to facilitate efficient electron transfer, extend excited-state lifetime, and sufficiently stable oxidation-reduction properties to achieve high catalytic efficiency. Current research focusses on hybrid systems including the integration of CAT and PS in soft functional matrices\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e,\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e, self-assemblies\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e and molecular PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT dyads\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. Such dyads enable, for example, self-repair mechanisms or mitigation of photodegradation\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e. For instance, supramolecular assemblies have been demonstrated for cobalt-ferrocyanides covalently coordinating PS molecules to form PS\u0026thinsp;\u0026minus;\u0026thinsp;WOC (water oxidation catalyst) dyads\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. Although the synthesis of molecular components offers high tunability for introducing covalent anchoring functionalities and provides high atom efficiency compared to semiconductors, the preparation of PS\u0026ndash;CAT dyads remains inherently complex, since the connecting bridging ligand is responsible for efficient intramolecular electron transfer from PS towards CAT during the lifetime of the excited state, while also maintaining high structural and redox stability of the bridge/spacer\u003csup\u003e33\u003c/sup\u003e. It is therefore highly attractive to integrate molecular PSs and CATs into ordered, high-surface area superstructures (inspired by the protein architectures of photosystems I/II), as this will enable translating the outstanding performance of homogeneous photoactive systems into stable heterogeneous platforms without significant synthetic effort. Tian et al. reported an elegant approach of self-assembled photocatalytic nanofibers based on block copolymers with crystallizable polyferrocenyldimethylsilane (PFS) cores and coronal segments functionalized with either the [Co(dmgH)\u003csub\u003e2\u003c/sub\u003e(py)Cl] catalyst bound to coronal poly(4-vinylpyridine) ligands (PFS-b-Cat) or bound BODIPY as PS (PFS-b-PS) that were co-assembled into low-dispersity, one-dimensional architectures ensuring the required close proximity of CAT and PS\u003csup\u003e14\u003c/sup\u003e. These nanofibers dispersed in solution showed high stability and activity (TON\u0026thinsp;\u0026gt;\u0026thinsp;7000 over 5 h, TOF\u0026thinsp;\u0026gt;\u0026thinsp;1400 h\u003csup\u003e-\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e) for H\u003csub\u003e2\u003c/sub\u003e evolution in MeOH/H\u003csub\u003e2\u003c/sub\u003eO (5%) using triethanolamine (TEOA) as a sacrificial electron donor (SED). Here, we demonstrate that nanoconfinement can direct the formation of solid, photoactive PS\u0026ndash;CAT assemblies of high stability, achieving spatial arrangements that promote efficient charge transfer without the need for bridging ligands, polymeric scaffolds or external mediators, thereby providing a simplified yet robust route toward functional photoactive PS\u0026ndash;CAT assemblies.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eImmobilization of PS\u0026ndash;CAT nanostructures\u003c/h2\u003e \u003cp\u003eRather than using covalently bridged PS\u0026ndash;CAT assemblies, we report supramolecular PS\u0026ndash;CAT nanowires deposited via scanning electrochemical cell microscopy (SECCM). This nanopipette-based technique benefits from nanoconfinement effects for electroless deposition\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e,\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e. In a previous study, we used SECCM to deposit cobaloxime salts as nano- and microspot arrays for accelerated screening experiments with respect to their HER activity using for the localized H\u003csub\u003e2\u003c/sub\u003e measurements scanning electrochemical microscopy (SECM) in combination with Pd-microelectrodes\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e. For the heterogeneous photocatalysis, ascorbic acid (AA) served as SED and [Ru(tbbpy)\u003csub\u003e2\u003c/sub\u003e(RRip)]Cl\u003csub\u003e3\u003c/sub\u003e (ip\u0026thinsp;=\u0026thinsp;1,3-dialkyl-1H-imidazol[4,5-f][1,10]phenanthrolinium (abbreviated as Ru(mmip)Cl\u003csub\u003e3\u003c/sub\u003e for R\u0026thinsp;=\u0026thinsp;Me) dissolved in the AA solution served as the PS\u003csup\u003e37,38\u003c/sup\u003e in these screening experiments of different cobaloxime salt spots. Ru(mmip)Cl\u003csub\u003e3\u003c/sub\u003e was selected for its high oxygen tolerance and high quantum yield of photoluminescence\u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e. Petermann et al.\u003csup\u003e39\u003c/sup\u003e, suggested an intermolecular catalytic cycle in homogeneous solution for the light-driven charge transfer of [Ru(tbbpy)\u003csub\u003e2\u003c/sub\u003e(RR\u0026rsquo;ip)]\u003csup\u003e3+\u003c/sup\u003e type PSs (including Ru(mmip)Cl\u003csub\u003e3\u003c/sub\u003e) and Co(dmgH)\u003csub\u003e2\u003c/sub\u003e-based catalysts, using AA as electron donor. It has been postulated that the N-heterocyclic carbene functional group, formed from the imidazolium unit under basic conditions, can coordinate to the catalytic active center, which facilitates the charge transfer\u003csup\u003e\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eHere, we mix [Ru(tbbpy)\u003csub\u003e2\u003c/sub\u003e(mmip)]\u003csup\u003e3+\u003c/sup\u003e\u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea\u003cb\u003e)\u003c/b\u003e as PF\u003csub\u003e6\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e salt (\u003cb\u003eRu(mmip)\u003c/b\u003e) with either [Co(dmgH)\u003csub\u003e2\u003c/sub\u003e(py)\u003csub\u003e2\u003c/sub\u003e]\u003csup\u003e+\u003c/sup\u003eBArF\u003csup\u003e-\u003c/sup\u003e (abbreviated \u003cb\u003eCoBArF\u003c/b\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb) or [Co(dmgH)\u003csub\u003e2\u003c/sub\u003e(py)\u003csub\u003e2\u003c/sub\u003e]\u003csup\u003e+\u003c/sup\u003e[Co(dmgBPh\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCl\u003csub\u003e2\u003c/sub\u003e]\u003csup\u003e-\u003c/sup\u003e (abbreviated \u003cb\u003eCo\u003c/b\u003e\u003csup\u003e\u003cb\u003e+\u003c/b\u003e\u003c/sup\u003e\u003cb\u003eCo\u003c/b\u003e\u003csup\u003e\u003cb\u003e-\u003c/b\u003e\u003c/sup\u003e, \u003cb\u003eFig. S1a\u003c/b\u003e)\u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e, which \u0026minus; among previously tested cobaloxime salts \u0026minus; showed the highest TONs in homogeneous HER and highest activity also in the screening experiments. The mixtures, dissolved in acetonitrile, was filled into the nanopipettes to perform local electroless depositions \u003cem\u003evia\u003c/em\u003e SECCM (for experimental details, see Supporting Information and \u003cb\u003eScheme S1\u003c/b\u003e). Initial experiments using the well characterized model PS [Ru(bpy)₃](PF\u003csub\u003e6\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e under identical conditions did not yield reproducible nanostructures and failed to produce well-defined nanowires (\u003cb\u003eFig. S2a\u003c/b\u003e). In contrast, \u003cb\u003eRu(mmip)\u003c/b\u003e consistently formed stable and homogeneous nanostructures, which motivated its selection for all subsequent experiments.\u003c/p\u003e \u003cp\u003eBy varying the PS:CAT molar ratio and the SECCM deposition parameters, we were able to control both the composition and morphology of the resulting supramolecular assemblies. Increasing the relative concentration of the PS in solution promotes extended one-dimensional growth, yielding nanowire whose diameters are defined by the nanopipette orifice (typically approx.100 nm). Nanowires with lengths up to several micrometres were reproducibly fabricated on both conductive and insulating substrates. At lower PS:CAT ratios, or under slow withdrawal conditions (5 \u0026micro;m s\u003csup\u003e-\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e), the deposition proceeds isotropically, producing hemispherical nanospots instead of nanowire. For a direct comparison of the photocatalytic performance, nanospots were prepared using identical PS:CAT ratios and solvent conditions while only altering the deposition conditions.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eSECCM (schematically depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea) offers a unique deposition strategy, whereby a nanoscale liquid meniscus defines a confined area enabling spatially controlled immobilization and assembly of molecular precursors directly onto the substrate. The nanoconfinement imposed by the meniscus plays a potentially decisive role in directing the assembly pathway. As already observed for crystallization processes under nanoconfinement conditions\u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u003c/sup\u003e, and as also shown here, the restricted geometry and rapid solvent evaporation can stabilize the formation of amorphous molecular aggregates while promoting a favorable arrangement between the charged CAT and PS for effective charge transfer.\u003c/p\u003e \u003cp\u003eThe positively charged imidazolium unit of \u003cb\u003eRu(mmip)\u003c/b\u003e appears to play a decisive role during the nanoconfined co-deposition, as reproducible nanowire formation was not observed when the model PS, [Ru(bpy)\u003csub\u003e3\u003c/sub\u003e](PF\u003csub\u003e6\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e, was used under otherwise identical conditions. This suggests that the specific, non-centrosymmetric/anisotropic charge distribution and intermolecular interactions introduced by the additional N-atoms as well as the C-H-acidic group of the imidazolium moiety may promote a more organized co-assembly with the also positively charged catalyst molecules. As discussed later and supported by molecular dynamics simulations, these interactions likely contribute to the formation of closely associated PS\u0026ndash;CAT domains that facilitate efficient photoinduced charge transfer\u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e,\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e. Previous studies have shown that in PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT aggregates, the PS is frequently the limiting factor during the photocatalytic process due to its propensity to undergo photodegradation\u003csup\u003e\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e. To sustain photocatalytic turnover and maximize electron transfer efficiency, usually an excess of PS relative to the CAT is used\u003csup\u003e\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e,\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e. For depositing nanostructures, we tested PS:CAT molar ratios of 1:1, 3:1, and 5:1 to identify conditions that favor both controlled nanostructured assembly and photocatalytic performance.\u003c/p\u003e \u003cp\u003eA systematic screening of molecular combinations and deposition parameters revealed, that depending on the experimental conditions nanowires or nanospots can be deposited. The formation pathway is predominantly governed by the interplay between solvent polarity, meniscus confinement and solvent evaporation (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb). In an optimized deposition regime, a short meniscus contact (2 s) and a rapid nanopipette withdrawal (150 \u0026micro;m s⁻\u0026sup1;) along with a rapid solvent evaporation rate drives an anisotropic assembly process resulting in the growth of 1D nanowires (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec,d). In contrast, slower evaporation rates (i.e., along with longer contact times and lower withdrawal speeds) lead to an isotropic deposition yielding nanospots. SECCM-based deposition strategies allow using the same concentration ratios while controlling the geometry of the PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT assembly (i.e., nanowire vs. nanospot) at various substrate surfaces by tuning the experimental deposition parameters, yet, maintaining the component ratios. Based on this screening process we could identify that the co-deposition of \u003cb\u003eRu(mmip)\u003c/b\u003e with \u003cb\u003eCoBArF\u003c/b\u003e at a 3:1 PS:CAT concentration ratio (dissolved in acetonitrile) yielded reproducible, well-defined nanowires across all tested substrates including gold, ITO, HOPG, silicon, glass polymer films and graphene TEM grids (\u003cb\u003eFig. S2\u003c/b\u003e). The SEM images revealed the formation of vertically oriented, high-aspect-ratio nanowires (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec) that break at the basis of the deposit after wetting the area with a water droplet (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed). Interestingly, the nanowires remained stable in solution in horizontal orientation (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec,d). Other conditions tested either failed to reproducibly form nanowires or resulted in isotropic nanospots with no obvious directional growth (\u003cb\u003eFig. S3a\u003c/b\u003e). Similarly, replacing acetonitrile with solvents of lower polarity (e.g., DMF, acetone) resulted in nanospots, despite mantaining the optimal PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT ratio and same experimental conditions. The use of the alternative catalyst (\u003cb\u003eCo⁺Co⁻, Fig. S4\u003c/b\u003e) resulted in nanowires, however, with irregular shapes (\u003cb\u003eFig. S4a\u003c/b\u003e) and less reproducible deposition behavior (\u003cb\u003eFig. S4b\u003c/b\u003e) and nanospots (\u003cb\u003eFig. S4d,f\u003c/b\u003e). This behavior underscores that the alignment of charge distribution between PS and CAT appears to favor a unidirectional growth. As shown in previous studies by our team, the SECCM-based deposition of pure cobaloxime catalysts was only feasible on carbonaceous materials such as amino-terminated carbon nanomembrane supports (CNMs)\u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e, whereas the co-deposition of nanostructured PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT assemblies is possible on conductive and non-conductive substrates highlighting the stabilizing role of \u003cb\u003eRu(mmip)\u003c/b\u003e during the formation of the co-deposited PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT assemblies.\u003c/p\u003e \u003cp\u003eHigh-resolution AFM and SEM imaging confirmed that the \u003cb\u003eRu(mmip)\u003c/b\u003e\u0026thinsp;\u0026minus;\u0026thinsp;\u003cb\u003eCoBArF\u003c/b\u003e nanowires are uniform with lengths up to 2 \u0026micro;m and diameters of 80\u0026ndash;100 nm (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec\u0026ndash;e). High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) combined with energy dispersive x-ray (EDX) spectroscopy for elemental mapping (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ef,g) revealed a homogeneous distribution of Ru, Co, P, and N throughout the nanowires, indicating that the two molecular components co-assemble without phase segregation, i.e., without forming into PS-rich and CAT-rich domains. Moreover, selected-area electron diffraction (SAED) patterns confirmed that both nanowires and nanospots are amorphous (\u003cb\u003eFig. S5\u003c/b\u003e), which is consistent with the expected influence of the nanoconfinement during co-deposition that is expected to suppress the formation of long-range crystallinity while maintaining local molecular ordering\u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eMolecular dynamics simulations\u003c/h3\u003e\n\u003cp\u003eTo elucidate the interpretation of the supramolecular architecture of the PS\u0026ndash;CAT assemblies, we first assessed their crystallinity. SAED patterns showed diffuse features, indicating that the assemblies are amorphous, and attempts to obtain co-crystals from bulk mixtures of the molecular components were likewise unsuccessful. Parallelly, the local organization and intermolecular interactions within the PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT supramolecular structures, can also be explored at the atomistic level using molecular dynamics (MD) simulations. Four representative systems differing in PS:CAT ratio (3:1 and 1:1) and solvent environment (with and without acetonitrile) were chosen to mimic the conditions encountered during deposition by SECCM. The 3:1 system in acetonitrile reproduces the composition within the pipette droplet prior to deposition, and the corresponding system in absence of ACN reflects the confined, post-evaporation environment within the nanostructure. The 1:1 system, in turn, serves as analogues for the less ordered nanospot assemblies. Analysis of the temporal evolution of noncovalent interactions over trajectories up to 1000 ns (\u003cb\u003eFig. S6\u003c/b\u003e and \u003cb\u003eS7\u003c/b\u003e) revealed clear and systematic differences between these environments and identified four dominant noncovalent interactions contributing to the supramolecular organization: salt bridges, π\u0026ndash;π stacking, hydrogen bonding, and π\u0026ndash;cation interactions (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn all simulations, salt bridges involving PF₆⁻ anions emerged as the most persistent and structurally significant interactions. In the 3:1 system containing acetonitrile (\u003cb\u003eFig. S6a\u003c/b\u003e), the number of salt bridges increased steadily during the first 500\u0026ndash;600 ns before reaching a plateau, consistent with the gradual self-organization of the ionic network interconnecting multiple PS units \u003cem\u003evia\u003c/em\u003e their imidazolium groups. Upon removal of the solvent, mimicking the progressive concentration and confinement during nanowire formation, these PF₆⁻-mediated bridges remained stable for the remainder of the trajectory, with only small fluctuations in amplitude \u003cb\u003eFig. S6b\u003c/b\u003e. The resulting configuration, depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea, consists of PF₆⁻ anions anchored between neighboring PSs, which effectively act as ionic crosslinkers that align PS units into directionally correlated domains. This ionic scaffold provides a plausible origin for the cooperative stabilization and anisotropic growth observed experimentally in nanowire architectures, where long-range electrostatic ordering compensates for the absence of covalent bonds between PS and CAT molecules. In contrast, simulations of 1:1 PS:CAT (\u003cb\u003eFig. S7\u003c/b\u003e), mirroring the formation of nanospots, showed a slightly lower number of salt bridges that were less persistent, and the trajectories lacked any indication of a sustained increase in ionic connectivity over time. The limited number of imidazolium sites restricts the probability of multipoint bridges, likely resulting in small, transient aggregates without directional propagation. When PF₆⁻ was removed in silico, the population of salt bridges was reduced, confirming that the counterion is not just a passive presence but critical for mediating intermolecular cohesion.\u003c/p\u003e \u003cp\u003eBeyond ionic interactions, MD simulations reveal how the aromatic stacking and π\u0026ndash;cationic interactions modulate the local packing within the assemblies. In the absence of solvent, π\u0026ndash;π stacking between bipyridine and imidazolium rings from the PS became more pronounced and stable, especially in the 1:1 system (\u003cb\u003eFig. S7b\u003c/b\u003e). The π\u0026ndash;π interactions exhibited the highest average number of contacts under these conditions, reflecting the propensity of both PS and CAT to cluster through dispersive interactions. However, these contacts tend to form short-range isotropic clusters rather than extended anisotropic architectures, consistent with the formation of spherical or irregular nanospot aggregates rather than elongated nanowires.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn contrast, in 3:1 nanowire-like systems, π\u0026ndash;π stacking contributed less to the overall stabilization and remained secondary to the PF₆⁻-driven ionic framework. This suggests a hierarchical assembly mechanism, in which the directional networks of salt bridges provide the backbone of the supramolecular scaffold, while the π\u0026ndash;π stacking fills the local gaps and adjusts the orientation between the molecules. H bonding, by contrast, was sporadic and short-lived throughout the simulations, occurring mainly within the CAT units and contributing little to the organization of the complex (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb-c). The MD trajectories further reveal that the PS and CAT tend to assemble into \u0026ldquo;electronically coupled\u0026rdquo; dyads, stabilized by a framework of short-range ionic and π-driven interactions that eliminate the need for any covalent tether (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec). Two classes of salt bridges dominate the interfacial stabilization. The first mechanism involves a second-sphere Ru\u0026middot;\u0026middot;\u0026middot;O interaction, in which the cobaloxime nitrosyl/oxime region forms a delocalized hydrogen-bond network (N\u0026ndash;O\u0026middot;\u0026middot;\u0026middot;H\u0026middot;\u0026middot;\u0026middot;O\u0026ndash;N) that orients the CAT relative to the PS. The second, more frequent motif involves the H\u0026ndash;bonding between the C2\u0026ndash;H proton of the imidazolium ring in the PS\u0026thinsp;\u0026minus;\u0026thinsp;i.e., the acidic hydrogen located between the two ring nitrogens\u0026thinsp;\u0026minus;\u0026thinsp;and the deprotonated oxime oxygen atoms of the CAT, generating persistent imidazolium\u0026middot;\u0026middot;\u0026middot;O⁻, as highlighted in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec. These interactions create a mixed ionic\u0026ndash;coordination interface that locks the two molecular components into close proximity while preserving their individual coordination environments.\u003c/p\u003e \u003cp\u003eSuperimposed on this ionic framework are π\u0026ndash;cation interactions between the pyridyl rings of the PS and the Co(III) center of the CAT, with centroid\u0026ndash;metal separations of 4.2\u0026ndash;4.6 \u0026Aring; and where the aromatic ring adopts approximately a planar orientation to the CoN₄ coordination plane (right magnified region in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec). Such geometries are ideal for through-space orbital overlap between the aromatic π-system and the partially filled Co d-orbitals, providing a direct pathway for photoinduced electron transfer from the excited \u003cb\u003eRu(mmip)\u003c/b\u003e chromophore to the catalytic center. Importantly, these π\u0026ndash;cation contacts appear with comparable frequency in all simulated environments, both in solution and under confined, solvent-free conditions. This fact indicates that the electronic communication between PS and CAT is an intrinsic property of their complementary charge distribution and frontier-orbital alignment, such that no additional chemical linker or external scaffold is required to promote charge transfer. This intrinsic proximity and coupling correlates to the efficient photocatalytic response of the nanowire assemblies and demonstrate that non-covalent ionic and π-interactions can act as self-assembling electronic junctions in molecular heterostructures.\u003c/p\u003e \u003cp\u003eGiven that nanowires and nanospots are composed of the same molecular building blocks, the emergence of such distinct architectures raises the question which parameters determine whether PF₆⁻ becomes an active part of the supramolecular assembly stability (i.e., nanowire architecture) or remains a passive counterion (\u003cem\u003ei.e\u003c/em\u003e., nanospot configuration)? The answer may lie in the deposition dynamics occurring during the SECCM experiment. Nanospots are formed \u003cem\u003evia\u003c/em\u003e a semi-static meniscus contact, where the solvent evaporates isotropically. This may create a symmetric and radially expanding concentration gradient leading to rapid disordered nucleation and local aggregation\u003csup\u003e\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u003c/sup\u003e. The outward capillary flow drives solutes from the center toward the edge of the contact area (meniscus), a phenomenon known as the coffee-ring effect. As a result, rapid and uncontrolled nucleation of the solute occurs at multiple sites producing many small aggregates rather than an ordered structure\u003csup\u003e\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u003c/sup\u003e. In this context, PF₆⁻ may be unable to integrate into bridging configurations, instead distributing randomly or migrating to the periphery, where it remains more vulnerable to leaching effects.\u003c/p\u003e \u003cp\u003eIn contrast, nanowires are generated by accelerated pulling of the nanopipette away from the surface after the droplet cell is formed causing directional solvent evaporation\u003csup\u003e\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u003c/sup\u003e which works best for acetonitrile as a low boiling and polar solvent. As the contact line recedes behind the moving meniscus, PS and CAT units are deposited progressively. This apparently creates an anisotropic concentration profile (i.e., a gradient primarily along the direction of motion) rather than a radially symmetric profile, which enables \u003cem\u003ecooperative assembly\u003c/em\u003e (i.e., molecules added later align and attach onto the earlier deposited ones) and PF₆⁻ may be subject to spatial constraints that are necessary to connect adjacent PS molecules \u003cem\u003evia\u003c/em\u003e salt bridges. The result is a directionally reinforced ionic network that defines the nanowire structure and accounts for its markedly improved stability at photocatalytically relevant illumination conditions.\u003c/p\u003e\n\u003ch3\u003eIn-situ H evolution\u003c/h3\u003e\n\u003cp\u003eTo the best of our knowledge, although supramolecular PS\u0026ndash;CAT nanofibers have been reported in homogeneous dispersion\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e, immobilized or free-standing assemblies composed solely of PS and HER-CAT components have not yet been explored for light-driven H₂ evolution. Given the dimensions of the \u003cb\u003eRu(mmip)\u003c/b\u003e/\u003cb\u003eCoBArF\u003c/b\u003e nanostructures, conventional gas chromatographic or spectroscopic analyses are not suitable. As previously reported, platinum-black (Pt-black)-modified microelectrodes\u003csup\u003e\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e,\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e\u003c/sup\u003e positioned above the horizontally aligned nanowire or nanospot arrays were successfully used to locally determine the H\u003csub\u003e2\u003c/sub\u003e evolution under illumination using SECM in substrate generation/tip collection (SG/TC) mode\u003csup\u003e\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e\u003c/sup\u003e (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea). As schematically shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb, upon photoexcitation at 470 nm, charge transfer within the PS is expected to proceed from the Ru center toward the imidazolium-functionalized phenanthroline ligand, as reported for Ru(mmip)Cl\u003csub\u003e3\u003c/sub\u003e systems by Petermann et al\u003csup\u003e39\u003c/sup\u003e. This electronic configuration likely facilitates efficient coupling with the nearby CAT in the co-assembled nanowires, enabling photoinduced electron transfer across the PS\u0026ndash;CAT interface by an oxidative quenching pathway (see \u003cb\u003eFig. S8\u003c/b\u003e). The H\u003csub\u003e2\u003c/sub\u003e evolution \u0026ndash; as postulated in the literature for cobaloximes \u0026ndash; involves a first single-electron reduction step from Co(III) to Co(II), which proceeds further either through a proton-coupled electron transfer (PCET) (Co(II) to Co(III)\u0026ndash;H) or through an additional metal-based single-electron reduction of Co(II) to Co(I) followed by protonation\u003csup\u003e\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e\u003c/sup\u003e. This step can occur \u003cem\u003evia\u003c/em\u003e, for instance, photoinduced electron transfer or via disproportionating charge migration within the structure. Ascorbate serves as solute reducing agent to \u003cb\u003eRu(mmip)\u003c/b\u003e and therefore sustains the catalytic cycle. At pH 4, AA (pK\u003csub\u003ea\u003c/sub\u003e = 4.2) partially exists in its monoanionic form (ascorbate), a potent and fast hole scavenger with a low oxidation potential (approx. 0.46 V vs. SCE)\u003csup\u003e\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e\u003c/sup\u003e. H\u003csub\u003e2\u003c/sub\u003e generated in the vicinity of the nanostructure arrays is then electrochemically quantified by the modified microelectrode positioned 20\u0026ndash;30 \u0026micro;m above the surface (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb). To validate the measurements, two different microsensors for H\u003csub\u003e2\u003c/sub\u003e detection were employed, Pt-black microelectrodes\u003csup\u003e\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e\u003c/sup\u003e, which detect H\u003csub\u003e2\u003c/sub\u003e through a dissociative adsorption step (Tafel step) forming chemisorbed hydrogen atoms (H*ₐd), followed by their electrochemical oxidation (Volmer step), (\u003cb\u003eFig. S9a\u003c/b\u003e), and Pd-modified microelectrodes\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e,\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e\u003c/sup\u003e, which relies on H₂ absorption into the Pd lattice and subsequent formation of Pd hydride (\u003cb\u003eFig. S9b).\u003c/b\u003e Both sensors provided consistent H\u003csub\u003e2\u003c/sub\u003e values (\u003cb\u003eFig. S9c\u003c/b\u003e), validating the robustness of the used detection methodology.\u003c/p\u003e \u003cp\u003eThe chronoamperometric measurements provided a direct and quantitative assessment of H\u003csub\u003e2\u003c/sub\u003e evolution at the nanostructures. The H\u003csub\u003e2\u003c/sub\u003e evolution rates were determined from the recorded currents by applying Faraday\u0026rsquo;s law taking the illumination time and the determined surface area of the nanowires in the 9 \u0026times; 9 arrays into account. The resulting current profiles shown in \u003cb\u003eFig. S10\u003c/b\u003e exhibit a characteristic current onset upon illumination and negligible signals under dark conditions, which indicates that the measured current results from the light-driven catalysis.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe arrangement of PS and CAT within the deposited nanostructures and the ratio of PS and CAT obviously plays a critical role for the duration and amount of the H\u003csub\u003e2\u003c/sub\u003e evolution rates. During initial experiments, the PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT ratios were studied using \u003cb\u003eRu(mmip)\u003c/b\u003e/\u003cb\u003eCo\u003c/b\u003e\u003csup\u003e\u003cb\u003e+\u003c/b\u003e\u003c/sup\u003e\u003cb\u003eCo\u003c/b\u003e\u003csup\u003e\u003cb\u003e-\u003c/b\u003e\u003c/sup\u003e nanospots (\u003cb\u003eFig. S11\u003c/b\u003e). The photocatalytic activity peaked at 0.034\u0026thinsp;\u0026plusmn;\u0026thinsp;0.004 fmol \u0026micro;m⁻\u0026sup2; s⁻\u0026sup1; for a 3:1 ratio, dropped by 15% to 0.029\u0026thinsp;\u0026plusmn;\u0026thinsp;0.003 fmol \u0026micro;m⁻\u0026sup2; s⁻\u0026sup1; at 1:1, and was completely suppressed at a ratio of 5:1. This strong dependence on the PS\u0026ndash;CAT ratio mirrors the behavior observed in nanoscale light-harvesting assemblies, whereby an optimal sensitizer-to-catalyst ratio maximizes energy- or charge-transfer efficiency by balancing light absorption and exciton delivery to catalytic centers\u003csup\u003e\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eAn optimal ratio ensures the required proximity for productive electron transfer from nearby excited PSs, whereby (\u003cem\u003ei\u003c/em\u003e) excess of PS leads to detrimental processes like self-quenching and exciton recombination, and (\u003cem\u003eii\u003c/em\u003e) excess of catalyst promotes unproductive quenching of excited states or underutilized catalytic sites\u003csup\u003e\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e\u003c/sup\u003e. In the deposited solid PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT nanostructures, charge transfer is dictated by the nanoscale distances between PS and CAT. At low ratios (1:1), the photon absorption density and exciton generation probability decrease, limiting the rate of photoinduced electron transfer and rendering many catalytic centers underutilized. At high ratios (5:1), the densely packed \u003cb\u003eRu(mmip)\u003c/b\u003e complexes may form a network where a significant fraction of excitations is trapped or relax non-productively, thereby hindering charge separation. Similar high local PS in multinuclear metal complexes or polymer-linked PS leads to triplet-triplet quenching as the dominant photophysical process preventing charge transfer. Moreover, the cationic PS molecules can electrostatically bind to and concentrate around the anionic cobalt catalyst sites, inducing local aggregation which may influence the efficiency of interfacial electron transfer, consistent with colloidal aggregation phenomena reported by Kirchhoff et al. for RuPS\u0026ndash;Co systems under homogeneous photochemical conditions\u003csup\u003e\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eBased on these considerations, a PS:CAT ratio 3:1 was selected. Nanowires composed of \u003cb\u003eRu(mmip)\u003c/b\u003e/\u003cb\u003eCoBArF\u003c/b\u003e at a PS:CAT ratio of 3:1 exhibited H\u003csub\u003e2\u003c/sub\u003e evolution rates of 0.33\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03 fmol \u0026micro;m⁻\u0026sup2; s⁻\u0026sup1;, nearly three times higher than nanospot assemblies with identical composition (0.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02 fmol \u0026micro;m⁻\u0026sup2; s⁻\u0026sup1;) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ec). In terms of H\u003csub\u003e2\u003c/sub\u003e evolution, we assume that only molecules located at or near the nanostructure surface are catalytically active, as diffusion-limited charge or proton transport likely restricts the participation of buried species. Since the H\u003csub\u003e2\u003c/sub\u003e production rate is normalized to the geometric area, the enhanced activity of nanowires compared to nanospots is not attributed simply to surface exposure but rather to the anisotropic supramolecular organization, which may promote directional electronic coupling along the π-stacked Ru backbones, as supported by MD presented above. Such an arrangement mimics the function of bridged PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT assemblies, where electronic communication between PS and CAT enables more efficient charge separation and transfer to catalytic sites.\u003c/p\u003e \u003cp\u003eThe robustness of the molecular nanowires was further demonstrated at extended photocatalytic conditions. Long-term illumination tests revealed that the high activity was preserved for at least 12 h, with reaction rates normalized to the exposed surface area remaining essentially constant (0.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04 fmol \u0026micro;m⁻\u0026sup2; s⁻\u0026sup1; after 4 h and 0.41\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02 fmol \u0026micro;m⁻\u0026sup2; s⁻\u0026sup1; after 12 h, Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ed). Such sustained performance of supramolecular assemblies is promising for molecular photocatalysts, which typically exhibit declining activity over longer experiments due to photodegradation under continuous irradiation\u003csup\u003e\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e,\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e\u003c/sup\u003e. For example, Ru(II)polypyridyl PSs are known to be instable in the excited state via population of Jahn-Teller distorted states, or in the oxidized/reduced forms. Very common are ligand dissociation in solution, including ligand loss (photo-substitution) which causes relatively fast deactivation of the photocatalytic system\u003csup\u003e\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e,\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e,\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e\u003c/sup\u003e. Likewise, several earth-abundant molecular proton-reduction catalysts (such as cobaloxime and polypyridine cobalt complexes) exhibit efficient H₂ generation initially. However, their stability is limited at prolonged irradiation leading to a rapid drop in H₂ evolution due to possible ligand exchange and decomposition\u003csup\u003e\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e,\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e\u003c/sup\u003e. In the nanowire architecture, the molecular components are effectively anchored within a solid structure which can mitigate the pathways of photodegradation observed in homogenous catalysis\u003csup\u003e\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e\u003c/sup\u003e. Indeed, since the PS is arranged with the CAT in the solid nanowire, we hypothesize that their ligands are less prone to dissociate, and the physical support and spatial confinement may help maintaining the integrity of the coordination sphere. For example, it has been reported that anchoring an Ir(III) PS on a macroscopic polymer substrate prevented its ligand dissociation, enabling\u0026thinsp;\u0026gt;\u0026thinsp;730 h of continuous photocatalytic H₂ evolution without deactivation\u003csup\u003e\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e\u003c/sup\u003e. This demonstrates that a well-designed support can significantly extend the lifetime of a molecular catalyst by suppressing ligand-driven decomposition.\u003c/p\u003e \u003cp\u003eWe also tested triethanolamine (TEOA, at pH\u0026thinsp;=\u0026thinsp;10.3) as SED, which is among the most commonly used electron donors in homogeneous and heterogeneous photocatalytic systems\u003csup\u003e\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e\u003c/sup\u003e. Although TEOA has an oxidation potential of approx. 0.8 V vs. SCE\u003csup\u003e\u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e62\u003c/span\u003e\u003c/sup\u003e, it exhibits slower electron transfer kinetics, and in aqueous media, only weakly quenches the photoexcited sensitizers\u003csup\u003e\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e\u003c/sup\u003e. Therefore, it was included for comparison of the H\u003csub\u003e2\u003c/sub\u003e evolution activity of the nanowires. AA (pH\u0026thinsp;=\u0026thinsp;4) showed higher activity (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ee) compared to TEOA (pH\u0026thinsp;=\u0026thinsp;10.3), which resulted in a 70% lower H\u003csub\u003e2\u003c/sub\u003e evolution activity (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ee). This finding is likely due to the stability of the active components at the different pH values. As shown in the SEM images recorded before and after illumination in \u003cb\u003eFig. S12a,b\u003c/b\u003e, the structural integrity of the nanowires is maintained in AA solution, whereas in the basic TEOA solution\u003csup\u003e\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e,\u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e,\u003c/sup\u003e the nanowires are barely visible after illumination (\u003cb\u003eFig. S12c,d)\u003c/b\u003e. The alkaline medium presumably destabilizes the imidazolium functional group\u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e of the PS in the nanowires via deprotonation, decreasing the overall charge of the Ru-PS to 2\u0026thinsp;+\u0026thinsp;as well as removing the acidic C\u0026ndash;H functionality essential for H-bridge-based stabilization, which results in severe morphological degradation. This behavior is consistent with the established base-induced pathways of imidazolium species, which proceed via deprotonation and carbene formation (\u003cb\u003eScheme S2\u003c/b\u003e)\u003csup\u003e\u003cspan additionalcitationids=\"CR66\" citationid=\"CR65\" class=\"CitationRef\"\u003e65\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e\u003c/sup\u003e. The disruption of the imidazolium functionality was further confirmed by time-of-flight secondary ion mass spectrometry (ToF-SIMS), which revealed the disappearance of the characteristic imidazolium fragment (\u003cb\u003eFig. S13\u003c/b\u003e). The stability of the PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT nanostructures is probably responsible for the long-term activity.\u003c/p\u003e\n\u003ch3\u003ePhotostability of the nanostructures\u003c/h3\u003e\n\u003cp\u003eA central challenge in heterogeneous photocatalysis lies in maintaining functional stability under photocatalytic conditions. For the supramolecular, solid \u003cb\u003eRu(mmip)\u003c/b\u003e/\u003cb\u003eCoBArF\u003c/b\u003e nanostructures, we investigated the stability of both, nanowires and nanospots, under prolonged continuous illumination with respect to the shape and morphology by atomic force microscopy (AFM), and chemical composition via nano-infrared (Nano-IR) imaging, and ToF-SIMS. The experimental approach is supported by the all-atom molecular MD simulations (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The AFM topography images shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e reveal the structural stability of the nanostructures under prolonged photocatalytic conditions. Nanowires and nanospots, both fabricated using a 3:1 PS:CAT ratio of \u003cb\u003eRu(mmip)\u003c/b\u003e and \u003cb\u003eCoBArF\u003c/b\u003e, were imaged in air in contact mode before and after irradiation in 0.1 M AA (pH\u0026thinsp;=\u0026thinsp;4). The comparison reveals a pronounced divergence in structural stability, suggesting different supramolecular organization of nanowires and nanospots despite identical chemical composition. In the case of nanowires (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea), the high-aspect-ratio structures remain clearly unchanged after 24 h of continuous illumination.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe height profile (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eb) extracted from several nanowires shows a negligible reduction of the nanowire base height from 278\u0026thinsp;\u0026plusmn;\u0026thinsp;7 nm in the pristine state to 271\u0026thinsp;\u0026plusmn;\u0026thinsp;8 nm after illumination for 24 h, corresponding to a 1.1% decrease. Whereas, the nanowire body, horizontally lying at the substrate (with an average height of ~\u0026thinsp;70 nm), remains essentially unaltered (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eb). In strong contrast, nanospots undergo fairly rapid degradation/dissolution under identical illumination conditions (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ec). Initially appearing as compact, hemispherical structures with uniform circular profiles and heights of 75\u0026thinsp;\u0026plusmn;\u0026thinsp;6 nm, the nanospots show signs of dissolution within just 2 h. After 5 h of continuous illumination, the nanospots are barely evident with the height reduced to 4\u0026thinsp;\u0026plusmn;\u0026thinsp;2 nm (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ed).\u003c/p\u003e \u003cp\u003eTo correlate the structural changes observed by AFM analysis with possible molecular changes and to gain insight into the nature of different activity, nano-IR and ToF-SIMS studies were performed before and after illumination of nanowires and nanospots. In an initial study, the vibrational bands of the PS and the CAT were assigned based on FTIR spectra of the individual components \u003cb\u003eRu(mmip)\u003c/b\u003e and \u003cb\u003eCoBArF\u003c/b\u003e as powders (\u003cb\u003eFig. S14\u003c/b\u003e). The vibrational band at 1310 cm⁻\u0026sup1; was assigned to the C\u0026ndash;N⁺ stretching vibration of the imidazolium moiety of \u003cb\u003eRu(mmip)\u003c/b\u003e\u003csup\u003e\u003cspan additionalcitationids=\"CR69\" citationid=\"CR68\" class=\"CitationRef\"\u003e68\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e70\u003c/span\u003e\u003c/sup\u003e, which can serve as a reliable marker for the PS. The P\u0026ndash;F stretching vibration at 1415 cm⁻\u0026sup1; is assigned to the PF₆⁻ counterion\u003csup\u003e\u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e70\u003c/span\u003e,\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e71\u003c/span\u003e\u003c/sup\u003e, while the N\u0026ndash;O stretching vibration at 1070 cm⁻\u0026sup1; corresponds to the oxime groups of the cobalt CAT\u003csup\u003e\u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e70\u003c/span\u003e,\u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e72\u003c/span\u003e,\u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e73\u003c/span\u003e\u003c/sup\u003e. The B\u0026ndash;C stretching vibration at 1114 cm⁻\u0026sup1; indicates the presence of the BArF⁻ counterion\u003csup\u003e\u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e70\u003c/span\u003e,\u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e74\u003c/span\u003e\u003c/sup\u003e. These specific bands for PS and CAT do not overlap and can be used for the identification of the cations and anions of the supramolecular PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT nanowires. Nano-IR phase maps of pristine and illuminated nanowires at specific frequencies are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea,b. For the pristine nanowires (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea), a clear signal was detected for the C\u0026ndash;N\u003csup\u003e+\u003c/sup\u003e band (1310 cm⁻\u0026sup1;) from the PS, P\u0026ndash;F (1415 cm⁻\u0026sup1;) from PF₆⁻, N\u0026ndash;O (1070 cm⁻\u0026sup1;) from the CAT, and B\u0026ndash;C (1114 cm⁻\u0026sup1;) from BArF⁻ corresponding to the absorption of nanowires. After 2 h of illumination under photocatalytic conditions, the nano-IR phase signal of the \u003cb\u003eRu(mmip)\u003c/b\u003e (1310 cm⁻\u0026sup1;), which correlates with the infrared absorption, remained clearly visible across the nanowire backbone. This indicates that the imidazolium functionality of the PS remains chemically and spatially retained. Similarly, the N\u0026ndash;O stretch of the Co-based CAT (1070 cm⁻\u0026sup1;) showed a persistent signal confirming the structural retention of the cobaloxime moiety. The PF₆⁻ signal (1415 cm⁻\u0026sup1;) also remains evident after illumination, whereas the BArF⁻ counterion exhibits a change in its characteristic absorption at 1114 cm⁻\u0026sup1; (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eb). The nano-IR phase maps are markedly different for the nanospots, as shown in the nano-IR phase maps (\u003cb\u003eFig. S15)\u003c/b\u003e. For the pristine and illuminated nspots (\u003cb\u003eFig. S15a\u003c/b\u003e), the nano-IR phase maps corresponding to the absorption of C\u0026ndash;N\u003csup\u003e+\u003c/sup\u003e from the PS, N\u0026ndash;O from the CAT, and B\u0026ndash;C from BArF⁻ are clearly evident. However, after 1 h of illumination (\u003cb\u003eFig. S15b\u003c/b\u003e), the P\u0026ndash;F signature at 1415 cm⁻\u0026sup1; exhibits a changed phase map in which only the inner region of the nanospot, which is the highest part and therefore reflect higher amount of PS-CAT seems to show absorption. This change in signal of the PF₆⁻ characteristic band in the outer rim of the spot indicates possible structural changes, which are confirmed via AFM (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ec,d) suggesting that PF₆⁻ may play a pivotal role in maintaining the structural integrity potentially resulting in the stability difference between nanowires and nanospots. The signals corresponding to the Ru-based PS (1310 cm⁻\u0026sup1;) and Co-based CAT (1070 cm⁻\u0026sup1;) show changes in the spot-size, which again correspond well with our AFM data but remain visible after illumination. Therefore, we hypothesize that the degradation of the nanospots is not due to the photodegradation of the functional units but may arise from the loss of the structural counterion (PF\u003csub\u003e6\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e) of \u003cb\u003eRu(mmip)\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eThe nano-IR imaging results align well with the ToF-SIMS data (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ec-h, and \u003cb\u003eFig. S16\u003c/b\u003e), although Co-containing fragments could not be detected, likely due to the low Co concentration and limited ToF-SIMS sensitivity. For the nanowires (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ec-h), the C\u003csub\u003e15\u003c/sub\u003eH\u003csub\u003e13\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e+\u003c/sup\u003e fragment of the \u003cb\u003eRu(mmip)\u003c/b\u003e imidazolium unit remains clearly detectable after 2 h of illumination (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ec,d), confirming that the PS core is chemically stable and remains embedded in the supramolecular structure. This fragment corresponds to the imidazolium moiety critical for both light absorption and supramolecular interaction (\u003cem\u003ee.g\u003c/em\u003e., π\u0026ndash;cation and salt bridges), indicating no photo-degradation of the PS under the given photocatalytic conditions. The PF\u003csub\u003e6\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e anion signal (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ee,f) persists after illumination, consistent with the nano-IR results for the nanowires. This suggests that PF\u003csub\u003e6\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e is structurally integrated \u003cem\u003evia\u003c/em\u003e salt bridges and not simply solvated or surface bound. In contrast, the signal related to the counterion (BArF⁻, C\u003csub\u003e32\u003c/sub\u003eF\u003csub\u003e24\u003c/sub\u003eH\u003csub\u003e12\u003c/sub\u003eB\u003csup\u003e\u0026minus;\u003c/sup\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eg,h) of the CAT significantly decreases upon illumination. This observation aligns with its weaker electrostatic interaction and larger steric bulk, which likely reduces its incorporation into the supramolecular structure and renders it more susceptible to anion exchange (e.g., with ascorbate anions from solution). Its partial loss, however, does not affect the structural integrity of the nanowires, consistent with the interpretation that the counterion BArF⁻ plays only a passive role in the nanowire architecture.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFor the nanospots, the C\u003csub\u003e15\u003c/sub\u003eH\u003csub\u003e13\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e+\u003c/sup\u003e imidazolium fragment (\u003cb\u003eFig. S16b,d\u003c/b\u003e) remains detectable after 2 h of illumination, confirming the chemical stability of the PS, independently on the nanostructure.\u003c/p\u003e \u003cp\u003eThe PF\u003csub\u003e6\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e secondary ion signal (\u003cb\u003eFig. S16e,g\u003c/b\u003e) signal notably decreases in intensity after illumination. disappears completely after illumination. The decrease in PF\u003csub\u003e6\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e intensity contrasts with the retention observed in the nanowires and highlights a clear structural vulnerability. It also supports the hypothesis that PF\u003csub\u003e6\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e is not integrated into the supramolecular backbone of the nanospots, yet, electrostatically associated making it highly susceptible to leaching under photocatalytic conditions. These observations are further demonstrated in the MS zoomed spectra recorded at the nanowires and nanospots for each important fragment that are depicted \u003cb\u003ein Fig. S17\u003c/b\u003e and \u003cb\u003eS18\u003c/b\u003e.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe present study demonstrates that simple molecular components – [Ru(tbbpy)₂(mmip)](PF\u003csub\u003e6\u003c/sub\u003e)₃ as PS and [Co(dmgH)₂(py)₂]⁺BArF⁻ as catalyst – may yield photocatalytic nanostructures with profoundly different performance and stability. Despite their identical molecular composition, nanowires and nanospots exhibit significantly different structural and functional resilience due to their distinct supramolecular architectures, which apparently originate from differences in deposition dynamics. For nanowires, the PF₆⁻ ion forms stabilizing salt bridges between photoactive units reinforced by directional solvent evaporation during SECCM-based deposition. In contrast, nanospots lack this ordered ionic framework leading to PF₆⁻ loss and dissolution upon illumination under photocatalytically relevant conditions. The nanowire architecture not only preserved its structural integrity but also showed increased photocatalytic performance with an approx. three-times higher H\u003csub\u003e2\u003c/sub\u003e evolution rate when compared with nanospots of the same composition ratio. This enhancement may arise from the anisotropic topology of the nanowires, which maximizes the exposure of the catalytic sites and supports directional charge transport along π-stacked Ru backbones while minimizing charge recombination. These findings suggest the pivotal role of counterion organization in dictating the stability of molecular photocatalysts in heterogeneous systems. The lack of reproducible formation of stable nanostructures with twofold positively charged standard ruthenium dye [Ru(bpy)\u003csub\u003e3\u003c/sub\u003e](PF\u003csub\u003e6\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e containing just two PF\u003csub\u003e6\u003c/sub\u003e\u003csup\u003e−\u003c/sup\u003e anions per ruthenium unit, while maintaining all other parameters, highlights the importance of these anions. The combination of operando activity studies via SECM and \u003cem\u003eex situ\u003c/em\u003e analysis using AFM, mass spectrometry, ToF-SIMS and nano-IR imaging augmented by associated MD simulations demonstrated that subtle shifts in supramolecular architecture governed by both molecular design and processing conditions may significantly affect the operational robustness of the system. These findings highlight the necessity of considering counterion behavior and deposition dynamics during rational design of next-generation photoactive nanostructures.\u003c/p\u003e \u003cp\u003eFrom a very general point of view, the presented findings offer a highly attractive perspective on future developments in artificial photosynthesis. Photocatalytically active supramolecular structures consisting of a PS, a bridging ligand (BL) and a CAT are often employed (see \u003cb\u003eFig. S19a\u003c/b\u003e) and allow for an in principle facile optimization of the catalytic performance by targeted adjustment of molecular structures. This promise has so far been hampered by the significant synthetic effort which needed to be placed in the BL. The herein presented supramolecular nanostructures have the potential to fulfill this promise as they are constructed from simple molecular building blocks ensuring sufficient interaction between PS and CAT without the need of a BL (see \u003cb\u003eFig. S19b\u003c/b\u003e) while at the same time possessing high stability and hour-long photocatalytic activity without decomposition. Electroless deposition of this architecture on several substrates has furthermore exemplified its technological appeal and may be transferred to other nanoconfinement scenarios.\u003c/p\u003e \u003cp\u003eFinally, our findings provide a blueprint for engineering self-assembly of molecular catalysts and sensitizers into electronically coupled and mechanically resilient architectures without the need of covalent linkers. By tuning deposition dynamics, solvent environment, and counterion identity – as demonstrated here by nanoconfinement – opens a pathway to long-range ionic networks that bridge molecular photochemistry with solid-state functionality.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003c/div\u003e \u003c/div\u003e\n\n "},{"header":"Methods","content":"\u003ch2\u003eChemical Reagents\u003c/h2\u003e\u003cp\u003eCommercially available reagents for syntheses were purchased from Sigma Aldrich, Alfa Aesar, Acros Organics, or TCI and were used without further purification. All aqueous solutions were freshly prepared with deionized water (18.0 MΩ cm, Elga Labwater; VWR Deutschland, Germany). Acetonitrile (≥ 99.9%), L-(+)-ascorbic acid (AA) (99.0-100.5%), and sodium hydroxide (NaOH) were purchased from VWR Chemicals (Darmstadt, Germany). Potassium tetrachloropalladate (II) (K\u003csub\u003e2\u003c/sub\u003ePdCl\u003csub\u003e4\u003c/sub\u003e) was purchased from Alfa Aesar (Thermo Fisher GmbH, Kandel, Germany). Hydrogen hexachloroplatinate (H\u003csub\u003e2\u003c/sub\u003ePtCl\u003csub\u003e6\u003c/sub\u003e), lead (II) nitrate (Pb(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e), triethanolamine (TEOA), and sodium sulfate (Na\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e) were purchased from Merck (Darmstadt, Germany).\u003c/p\u003e\u003ch3\u003eSynthesis of CAT and PS\u003c/h3\u003e\u003cp\u003e[Co(dmgH)\u003csub\u003e2\u003c/sub\u003e(py)\u003csub\u003e2\u003c/sub\u003e]\u003csup\u003e+\u003c/sup\u003eBArF\u003csup\u003e−\u003c/sup\u003e (\u003cb\u003eCoBArF\u003c/b\u003e) and [Ru(tbbpy)\u003csub\u003e2\u003c/sub\u003e(mmip)](PF\u003csub\u003e6\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e (\u003cb\u003eRu(mmip)\u003c/b\u003e)were synthesized as described previously\u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e,\u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e75\u003c/span\u003e\u003c/sup\u003e. For \u003cb\u003eCoBArF\u003c/b\u003e, first, a cobaloxime-based double complex with formula [Co(dmgH)\u003csub\u003e2\u003c/sub\u003e(py)\u003csub\u003e2\u003c/sub\u003e]\u003csup\u003e+\u003c/sup\u003e[Co(dmgBPh\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003eCl\u003csub\u003e2\u003c/sub\u003e]\u003csup\u003e−\u003c/sup\u003e (\u003cb\u003eCo\u003c/b\u003e\u003csup\u003e\u003cb\u003e+\u003c/b\u003e\u003c/sup\u003e\u003cb\u003eCo\u003c/b\u003e\u003csup\u003e\u003cb\u003e−\u003c/b\u003e\u003c/sup\u003e) was prepared by dissolving [Co(dmgH)\u003csub\u003e2\u003c/sub\u003e(py)Cl] (200 mg) in anhydrous acetonitrile (9.0 mL) and adding triphenylborane (242 mg). The mixture was stirred in anhydrous acetonitrile (9.0 mL) at room temperature for 5 h and the resulting precipitate was collected and washed with diethyl ether, ethanol, and water, to yield pure \u003cb\u003eCo\u003c/b\u003e\u003csup\u003e\u003cb\u003e+\u003c/b\u003e\u003c/sup\u003e\u003cb\u003eCo\u003c/b\u003e\u003csup\u003e\u003cb\u003e−\u003c/b\u003e\u003c/sup\u003e as a brown solid (220 mg, 77%). The salt (20 mg) was suspended in chloroform (6 mL) and 22 mg NaBArF was added. The reaction mixture was stirred for 20 min and quenched with 7 mL of water, with the formation of two phases. The organic phase was collected, washed twice with water (2 x 10 mL), and dried over MgSO\u003csub\u003e4\u003c/sub\u003e. The resulting beige/ orange solid was washed with cold diethyl ether, yielding 9 mg of pure \u003cb\u003eCoBArF\u003c/b\u003e (39%).\u003c/p\u003e\u003cp\u003e \u003cb\u003eCo-deposition of PS and CAT microstructures\u003c/b\u003e \u003cb\u003evia\u003c/b\u003e \u003cb\u003eSECCM\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe SECCM depositions were carried out by a lab-built SECCM setup, as previously described\u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e. The setup is controlled using LabVIEW 2016 software (National Instruments, Austin, USA), assisted by an FPGA card (PCIe 7851, National Instruments, Austin, USA). LabVIEW software is part of the publicly available Warwick Electrochemical Scanning Probe Microscopy (WEC-SPM) software\u003csup\u003e\u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e76\u003c/span\u003e\u003c/sup\u003e. Current measurements were performed with a low-noise current preamplifier (SR570, Stanford Research Systems, USA). Nanopipettes with orifices of 100 nm or 500 nm (measured accurately by SEM) were made from quartz theta capillaries (1.2 mm OD, 0.9 mm ID, Sutter Instruments, Novato, USA) using a laser pipette puller (P-2000, Sutter Instruments, Novato, USA). The nanopipettes were back-filled with \u003cb\u003eRu(mmip)\u003c/b\u003e PS and \u003cb\u003eCoBArF\u003c/b\u003e catalyst solution in acetonitrile and different PS:CAT ratios. The following concentration ratios were used: PS:CAT 1:1 (0.4 mM PS, 0.4 mM CAT), 3:1 (1.2 mM PS, 0.4 mM CAT), and 5:1 (2 mM PS, 0.4 mM CAT). Ag wires were inserted in the back opening of each barrel serving as quasi-reference counter electrodes (QRCEs). The nanopipette was mounted on a \u003cem\u003ez\u003c/em\u003e-piezo positioner (P-753.2CD, Physics Instruments, Karlsruhe, Germany), and perpendicular to the substrate, which was mounted on an \u003cem\u003ex-y\u003c/em\u003e piezo table (P-541.2CD, Physics Instruments, Karlsruhe, Germany). A micro-positioner (MTS25-Z8, Thorlabs GmbH, Bergkirchen, Germany) assisted by a digital camera (PL-B776U, PixeLink, Ottawa, Canada) and a cold light source (MI-150, Edmund Optics, Mainz, Germany), was used for the manual positioning of the pipette at a distance of approx. 20 µm above the substrate. An automated software-controlled approach was performed by applying a potential of + 25 mV between the two QRCEs and moving the pipette with a rate of 200 nm s\u003csup\u003e− 1\u003c/sup\u003e until the droplet contact was formed, indicated by a change in the DC ion current measured between the two QRCEs. To form the nanospots, the nanopipette was then kept in contact with the substrate for 5 s to favor the co-deposition of the photocatalytic components. After this time, the nanopipette was retracted with a speed equal to 5 µm s\u003csup\u003e− 1\u003c/sup\u003e and moved automatically to the next deposition site via hopping mode SECCM. To form the nanowires, the nanopipette was kept in contact with the substrate for 2 s and withdrawn with a speed of 150 µm s\u003csup\u003e− 1\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003e \u003cb\u003ePreparation of H\u003c/b\u003e \u003csub\u003e \u003cb\u003e2\u003c/b\u003e \u003c/sub\u003e \u003cb\u003eamperometric microsensors and in-situ H\u003c/b\u003e\u003csub\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sub\u003e \u003cb\u003emeasurements\u003c/b\u003e \u003cb\u003evia\u003c/b\u003e \u003cb\u003eSECM\u003c/b\u003e\u003c/p\u003e\u003cp\u003eTwo types of H\u003csub\u003e2\u003c/sub\u003e microsensors were used for the quantification of H\u003csub\u003e2\u003c/sub\u003e evolution at the PS − CAT nanostructures: a Pd-modified Au-Ni microelectrode\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e and a platinum-black (Pt-black)-modified microelectrode\u003csup\u003e\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e,\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e\u003c/sup\u003e. The 25-µm-diameter disk-shaped Au-Ni and Pt microelectrodes were fabricated by melting the Au-Ni or Pt microwire (Goodfellow, Bad Nauheim, Germany) into borosilicate glass (glass capillaries (Hilgenberg, Malsfeld, Germany) following well-established procedures\u003csup\u003e\u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e77\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe preparation of the Pd-modified Au-Ni microsensor has been described elsewhere\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e. Briefly, a three-electrode setup with the Au-Ni microelectrode as a working electrode, an Ag/AgCl/ KCl, 3M reference electrode, and a Pt counter electrode were used. In the first step, the Au-Ni microelectrode was etched in 0.1 mol L\u003csup\u003e− 1\u003c/sup\u003e KCl by cyclic voltammetry (15 cycles in the potential range of + 0.20 V to + 0.90 V and scan rate of 0.20 V s\u003csup\u003e− 1\u003c/sup\u003e). In a second step, Pd was electrochemically deposited onto the etched Au-Ni microelectrode in 20 mmol L\u003csup\u003e− 1\u003c/sup\u003e K\u003csub\u003e2\u003c/sub\u003ePdCl\u003csub\u003e4\u003c/sub\u003e using pulsed deposition (150 pulse cycles with a potential pulse sequence of + 0.35 V/0.5 s; +0.60 V/ 0.5 s). The Pt microelectrode was modified by electro-platinization, i.e., by depositing Pt-black onto the bare Pt microelectrode\u003csup\u003e\u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e78\u003c/span\u003e\u003c/sup\u003e. H\u003csub\u003e2\u003c/sub\u003ePtCl\u003csub\u003e6\u003c/sub\u003e (30.6 mmol L\u003csup\u003e− 1\u003c/sup\u003e in PBS) is reduced in the presence of Pb(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e (0.65 mmol L\u003csup\u003e− 1\u003c/sup\u003e) at a constant potential of -0.06 V for 40 s.\u003c/p\u003e\u003cp\u003eThe H\u003csub\u003e2\u003c/sub\u003e calibration procedures of both sensors, as previously reported\u003csup\u003e\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e\u003c/sup\u003e, was performed in 0.1 mol L\u003csup\u003e− 1\u003c/sup\u003e ascorbic acid (pH 4) in a closed glass chamber. Different concentrations of H\u003csub\u003e2\u003c/sub\u003e were obtained by mixing N\u003csub\u003e2\u003c/sub\u003e with pure H\u003csub\u003e2\u003c/sub\u003e gas in varying proportions, using a mass flow controller (Bronkhorst GmbH, Kamen, Germany). The detection and quantification of H\u003csub\u003e2\u003c/sub\u003e was obtained \u003cem\u003evia\u003c/em\u003e chronoamperometry, by applying a potential equal to -0.6 V vs. Ag/AgCl (Pd sensor) or -0.05 V vs. Ag/AgCl (Pt-black sensor).\u003c/p\u003e\u003cp\u003eThe HER measurements were performed either using a custom-build SECM setup or a SECM instrument from Sensolytics GmbH (Bochum, Germany), equipped with, respectively, a Palmsens4 potentiostat (Palmsens, Houten, Netherlands) or an Autolab/PGSTAT302N bi-potentiostat (Metrohm, Germany). All SECM studies were performed in a three-electrode setup with the microelectrode serving as the working electrode, an Ag/AgCl quasi-reference electrode, and a Pt wire as the counter electrode. To evaluate the photocatalytic activity of the PS − CAT systems, the H\u003csub\u003e2\u003c/sub\u003e sensor was positioned above the PS − CAT array and all measurements were performed in a 0.1 mol L\u003csup\u003e− 1\u003c/sup\u003e ascorbic acid argon-purged solution (pH 4) and at a tip-surface distance of approx. 20 − 30 µm. To determine the tip-surface distance, the sample was first immersed in an aerated ascorbic acid solution and oxygen was used as the electroactive species to perform approach curves in SECM feedback mode. Once the tip-surface distance was determined, the solution was changed to an O\u003csub\u003e2\u003c/sub\u003e-free solution, and a potential of -0.60 V (Pd-modified sensor) or -0.05 V (Pt-black sensor) was applied. All experiments were performed under an argon atmosphere. A 400 µm optical fiber (MT-28L01, Thorlabs GmbH, Bergkirchen, Germany) connected to a 21.8 mW blue LED (M470F3, Thorlabs GmbH) was used for illumination.\u003c/p\u003e\u003ch2\u003eAFM, SEM, and STEM-EDX measurements\u003c/h2\u003e\u003cp\u003eAFM measurements were performed using a 5500 AFM/SPM microscope (Keysight Technologies, AZ, USA). AFM contact mode images were recorded in air using silicon nitride probes (ORC-8, Bruker AFM probes, CA, USA; nominal spring constant of 0.1 N m\u003csup\u003e− 1\u003c/sup\u003e) and a scan speed of 0.50 ln s\u003csup\u003e− 1\u003c/sup\u003e. PicoView 1.20 and MoutainSPIP® v. 9 (Digital Surf, France) software were used to perform, respectively, the AFM experiments and the data processing. AFM measurements were recorded at pristine samples and samples treated under photocatalytic conditions to investigate the stability of the nanowires/nanospots structures. For the treatment under photocatalytic conditions, the samples were immersed in a 0.1 M AA solution (pH 4 adjusted with concentrated NaOH) previously purged with argon and illuminated for up to 24 h with a blue LED (λ = 470 nm). During the illumination, the samples were kept under an argon atmosphere. After illumination, the substrates were washed three times with ultrapure water, air-dried, and imaged with AFM.\u003c/p\u003e\u003cp\u003eSEM images of the nanostructures were obtained with a Helios Nanolab 600 FIB/SEM (ThermoFisher, FEI, Eindhoven, Netherlands) operating at 1–3 kV and beam currents of 86 pA by using the in-lens detector (immersion mode) of the instrument. Data processing was done using the Fiji software package (ImageJ 1.53t).\u003c/p\u003e\u003cp\u003eThe elemental composition and elemental mapping of the immobilized nanostructured were done using a ThermoFisher Talos F200X transmission electron microscope (TEM) operated in scanning mode (STEM) for simultaneous acquisition of high-angle annular dark field (HAADF) images and spatially-resolved energy dispersive x-ray (EDX) spectra. Those spectra were background-subtracted and used to generate elemental maps.\u003c/p\u003e\u003ch2\u003eToF-SIMS studies\u003c/h2\u003e\u003cp\u003eTime-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses were conducted using a ToF-SIMS M6 Plus instrument (IONTOF GmbH, Münster, Germany) equipped with a Bi-cluster LMIG primary ion source. Spectra and secondary ion images were acquired in both positive and negative ion polarities under “delayed extraction” conditions. A pulsed Bi\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e++\u003c/sup\u003e primary ion beam was operated at 60 keV with a cycle time of 100 µs and a beam defining aperture of 110 µm. The primary ion current, measured prior to analysis using an internal Faraday cup, was approximately 0.06 pA. Each dataset was collected over a surface area of 25 × 25 µm² with an image resolution of 512 × 512 pixels. The achieved mass resolution at \u003cem\u003em\u003c/em\u003e/\u003cem\u003ez\u003c/em\u003e 29 was about 4500 \u003cem\u003em\u003c/em\u003e/Δ\u003cem\u003em\u003c/em\u003e (FWHM). Data acquisition was terminated once a total ion fluence of ~ 8 × 10¹² ions/cm² had been reached.\u003c/p\u003e\u003cp\u003ePositive ion spectra were mass-calibrated using the following reference peaks: C\u003csub\u003e2\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003e\u003csup\u003e+\u003c/sup\u003e, C\u003csub\u003e3\u003c/sub\u003eH\u003csub\u003e7\u003c/sub\u003e\u003csup\u003e+\u003c/sup\u003e, C\u003csub\u003e4\u003c/sub\u003eH\u003csub\u003e9\u003c/sub\u003e\u003csup\u003e+\u003c/sup\u003e, Au\u003csup\u003e+\u003c/sup\u003e, Au\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e+\u003c/sup\u003e, Au\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e+\u003c/sup\u003e. Negative ion spectra were calibrated using the ions C\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e−\u003c/sup\u003e, Cl\u003csup\u003e−\u003c/sup\u003e, C\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e−\u003c/sup\u003e, C\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e−\u003c/sup\u003e, Au\u003csup\u003e−\u003c/sup\u003e, Au\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e−\u003c/sup\u003e.\u003c/p\u003e\u003ch2\u003eNano-IR imaging\u003c/h2\u003e\u003cp\u003eNano-IR imaging was performed using a NeaSNOM (Attocube, Germany) instrument, in which the AFM operates in tapping mode with an in-house 60 nm platinum-coated AFM tip (Arrow NCR, NanoWorld) oscillating at an amplitude of 75 nm at the detected mechanical resonance of ~ 236 kHz. Nano-IR imaging utilized a mid-infrared quantum cascade laser (Daylight Solutions, USA) with an approximate power of 1.5–2.2 mW, and a Michelson interferometer analyzed the tip-scattered light using a liquid nitrogen cooled mercury cadmium telluride detector. Pseudoheterodyne detection provides background-free and simultaneous detection of optical amplitude and phase signals, with the phase signal corresponding to the IR absorption. The images are acquired with 256 x 256 px grid and an integration time of 3 ms/px. The images at 3rd order demodulation are presented, after background and scar correction of the raw data. Phase unwrapped for some of the maps. The preprocessing is performed using Gwyddion 2.61\u003csup\u003e79\u003c/sup\u003e and MoutainSPIP® v. 9 (Digital Surf, France).\u003c/p\u003e\u003ch2\u003eMolecular dynamics simulations\u003c/h2\u003e\u003cp\u003eAll molecular structures were initially optimized deploying DFT in the Jaguar optimization tool (Schrödinger Suite)\u003csup\u003e\u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e80\u003c/span\u003e,\u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e81\u003c/span\u003e\u003c/sup\u003e. The CAT and PF6 complex were optimized using B3LYP-D3/6-31G(d,p). The PS and BArF complex were optimized using the B3LYP-D3/def2-SVP level of theory, to have an appropriate balance between accuracy and computational efficiency. To model molecular aggregation and self-assembly behavior, disordered multicomponent systems were constructed with varying stoichiometric ratios. For the 1:1 system, the simulation box contained 60 CAT, 60 BARF, 60 PS molecules, 180 PF₆ counterions. For the 1:3 system, 20 CAT, 20 BARF, 60 PS molecules, 180 PF₆ counterions were included. To simulate realistic solvent conditions, each system was solvated with 6000 acetonitrile (ACN) molecules. All systems were equilibrated prior to production runs. Molecular dynamics (MD) simulations were performed using Desmond module (Schrödinger Suite) under periodic boundary conditions. Each system was equilibrated in the NVT ensemble at 300 K, followed by a production simulation in the NPT ensemble at 300 K and 1.01325 bar. A 2-fs integration time step was employed, and trajectories were recorded every 2000ps. Each simulation was run for 1000 ns (1 µs) to ensure adequate sampling of molecular motion, aggregation, and nano structuring behavior. Trajectories were subsequently analyzed to evaluate intermolecular interactions, aggregation patterns, and solvent-mediated assembly.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe data supporting the findings of this study are available within this Article and its Supplementary Information. Data are available from the corresponding authors upon request.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe project is funded by the Deutsche Forschungsgemeinschaft (DFG – German Research Foundation) – project number 364549901 – TRR 234, subprojects A4, C2, C4, B7 and Z2. The authors acknowledge the FIBCenter UUlm and Dr. Gregor Neusser (Institute of Analytical and Bioanalytical Chemistry, Ulm University) for the FIB-SEM measurements. \u0026nbsp;Savelii Filipkov (Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena) is acknowledged for the support during Nano-IR measurements. The authors also acknowledge support by the state of Baden-Württemberg through bwHPC and the German Research Foundation (DFG) through Grant no INST 40/575-1 FUGG (JUSTUS 2 cluster) as well as INST 162/544-1 FUGG. VD, WW \u0026amp; \u0026nbsp;TS also acknowledge funding \u0026nbsp;by the DFG (SFB NOA Nr 398816777, C2) and the Bundesministerium für Forschung, Technologie und Raunfahrt (BMFTR) funding program Photonics Research Germany („LPI-BT1“, FKZ: 13N15466) and integrated into the Leibniz Center for Photonics in Infection Research (LPI). The LPI initiated by Leibniz-IPHT, Leibniz-HKI, UKJ and FSU Jena is part of the BMBF national roadmap for research infrastructures.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEva Oswald data curation, SECCM depositions and writing of the draft. Giada Caniglia: Conceptualization, data curation, writing, review and editing. Anna-Laurine Gaus, Martin Lämmle and Alexander K. Mengele: Conceptualization and synthesis of catalysts and photosensitizers. Soumya Rajpal: molecular dynamics simulation and data curation. Giuseppe Ragusano and Marcus Rohnke: ToF-SIMS studies and data curation. Tanveer Shaik, Wei Wang: Nano-IR studies and data curation. Robert Leiter, Johannes Biskupek and Ute Kaiser: HAADF-STEM, EDX, SADPs measurements and data curation. Max von Delius, Volker Deckert, Sven Rau, Volker Deckert and Boris Mizaikoff:\u0026nbsp;\u0026nbsp;Supervision, funding acquisition, review, and editing. Christine Kranz: \u0026nbsp;Conceptualization, supervision, project administration, funding acquisition, writing, review, and editing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAdditional information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSupplementary information.\u0026nbsp;\u003c/strong\u003eThe online version contains supplementary material available at https://doi.org/...\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eHansora, D.; Mehrotra, R.; Noh, E.; Yoo, J. W.; Kim, M.; Byun, W. J.; Park, J.; Jang, J.-W.; Seok, S. Il; Lee, J. S. 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Gwyddion: An Open-Source Software for SPM Data Analysis. \u003cem\u003eOpen Physics\u003c/em\u003e \u003cstrong\u003e2012\u003c/strong\u003e, \u003cem\u003e10\u003c/em\u003e (1), 181\u0026ndash;188. https://doi.org/10.2478/s11534-011-0096-2.\u003c/li\u003e\n\u003cli\u003eSchr\u0026ouml;dinger Release 2024-4 Desmond Molecular Dynamics System; Schr\u0026ouml;dinger: New York, NY, 2016.\u003c/li\u003e\n\u003cli\u003eMaterials Science Suite Release 2024-4; Schr\u0026ouml;dinger, LLC: New York, NY, 2018.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-8237178/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8237178/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eControlling the nanoscale organization of photosensitizer\u0026ndash;catalyst (PS\u0026ndash;CAT) assemblies into high-surface-area superstructures holds great promise for enhancing photochemical energy conversion yet remains a formidable challenge. We report the nanoconfined deposition of supramolecular photoactive architectures solely composed of cobaloxime-based catalytic salts (CAT) and an imidazophenanthroline-containing ruthenium photosensitizer (PS) salt using via scanning electrochemical cell microscopy (SECCM). This nanoconfinement strategy enables the controlled formation of PS\u0026ndash;CAT supramolecular structures ranging from nanospots to nanowires with a diameter of approx. 80\u0026ndash;100 nm that catalyze light-driven hydrogen evolution in the absence of covalent linkers. The supramolecular nanowires, formed solely by tuning the nanopipette retraction speed from the surface, exhibit markedly enhanced photoactivity and stability compared to deposited nanospots using the same PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT ratio. Correlative time-of-flight secondary ion mass spectrometry (ToF-SIMS) and nano-infrared (nano-IR) imaging, supported by molecular dynamics simulations, revealed distinct molecular changes of the different nanostructures, highlighting the crucial role of PF₆⁻ \u0026minus; the counterion of the PS\u0026thinsp;\u0026minus;\u0026thinsp;in stabilizing the supramolecular framework. The presented approach allows designing an optimum arrangement of PS\u0026thinsp;\u0026minus;\u0026thinsp;CAT freestanding supramolecular architectures for improved stability and activity without the need for scaffolds and bridging ligands.\u003c/p\u003e","manuscriptTitle":"Supramolecular nanowires solely composed of cobalt and ruthenium salts enable enhanced stability and activity in light-driven hydrogen evolution","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-30 00:09:07","doi":"10.21203/rs.3.rs-8237178/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"c945710b-f1b2-4d2b-a3d4-68a8313dcee5","owner":[],"postedDate":"December 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":60110613,"name":"Physical sciences/Chemistry/Catalysis"},{"id":60110614,"name":"Physical sciences/Nanoscience and technology/Nanoscale materials/Nanowires"}],"tags":[],"updatedAt":"2025-12-30T00:09:07+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-30 00:09:07","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8237178","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8237178","identity":"rs-8237178","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}