Effectiveness of strain and dopants on breaking the activity-stability trade-off of RuO2 acidic oxygen evolution electrocatalysts

Effectiveness of strain and dopants on breaking the activity-stability trade-off of RuO2 acidic oxygen evolution electrocatalysts | 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 Effectiveness of strain and dopants on breaking the activity-stability trade-off of RuO 2 acidic oxygen evolution electrocatalysts Hyoyoung Lee, Yang Liu, Yixuan Wang, Hao Li, Min Kim, Mingbo Wu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4721957/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 17 Feb, 2025 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract Ruthenium dioxide (RuO₂) electrocatalysts for acidic oxygen evolution reaction (OER) suffer from mediocre activity and rather instability induced by high Ru-O covalency. Here, the tensile strained Sr 0.1 Ta 0.1 Ru 0.8 O 2-x (TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2-x ) nanocatalysts were synthesized via a molten salt-assisted quenching strategy. The TS spacially elongates the Ru-O bond and reduces covalency, thereby inhibiting the lattice oxygen participation and structural decomposition. The synergistic electronic modulations among Sr-Ru-Ta groups both optimize deprotonation on oxygen sites and intermediates absorption on Ru sites, lowering the OER energy barrier. Those result in a well-balanced activity-stability profile, confirmed by comprehensive experimental and theoretical analyses. Our TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2-x electrode demonstrated an overpotential of 166 mV at 10 mA cm -2 in 0.5 M H 2 SO 4 and an order of magnitude higher S-number, indicating exceptional stability compared to bare Sr 0.1 Ta 0.1 Ru 0.8 O 2-x . It exhibited degradation rates of 0.02 mV/h at 10 mA cm -2 over 1000 h and 0.25 mV/h at 200 mA cm -2 over 200 h. This study elucidates the effectiveness of tensile strain and strategic doping in enhancing the activity and stability of Ru-based catalysts for acidic OER. Physical sciences/Chemistry/Electrochemistry/Electrocatalysis Physical sciences/Materials science/Nanoscale materials/Synthesis and processing Physical sciences/Nanoscience and technology/Nanoscale materials/Structural properties Physical sciences/Chemistry/Energy Physical sciences/Materials science/Materials for energy and catalysis/Electrocatalysis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Introduction Proton Exchange Membrane Water Electrolyzers (PEMWE) offer significant advantages, including low operating temperatures, high voltage efficiency, high current densities, and excellent compatibility, rendering them a promising green hydrogen production technology with substantial development potential 1,2,3 . However, the sluggish reaction kinetics of anodic oxygen evolution reaction (OER) in PEMWE often demand increased energy consumption, significantly reducing operational efficiency and impeding its widespread adoption. Iridium oxide (IrO 2 ) remains the sole commercially viable anodic catalyst for PEMWE due to its promising anti-corrosive quality in acidic conditions. Unfortunately, the scarcity and high cost of iridium severely limit the large-scale implementation of PEMWE 3,4,5,6,7 . Ruthenium dioxide (RuO 2 ) has emerged as a potential alternative catalyst for acidic OER due to its relatively higher intrinsic activity and rather lower cost (about 17% price of Ir metal) 3,8 . Nonetheless, unsatisfied activity and even more serious degradation achieved on RuO 2 in acidic OER conditions still restrict its further consideration for commercial application 4,8,9,10,11,12 . Therefore, understanding the origin behind those present phenomena is the prerequisite for simultaneously improving the activity and stability of RuO 2 catalysts. In principle, once the OER on RuO 2 mainly follows the adsorbate evolution mechanism (AEM). Overcoming the scaling relation of the adsorption energies between *OH and *OOH key intermediates is crucial, and it can always be realized by the foreign atom's modulations towards the enhanced activity eventually. The lattice oxygen-mediated mechanism (LOM) leads to the formation of numerous oxygen vacancies (V O ) and induced over-oxidized Ru species (Ru x>4+ ) due to the strong covalent Ru-O bonds. Whereas resulting in higher activity, the accompanying soluble Ru (e.g., RuO 4 ) derivatives leaching out, active sites rapid dissolution, crystal structure collapse, and catalytic performance deterioration over extended periods are hardly avoidable 13,14,15,16,17 . Thus, it is urgent yet challenging to discover a strategy that can effectively circumvent the occurrence of LOM while also optimizing the absorption behavior of multiple AEM key species on RuO 2 electrocatalysts. It has been proved that the metal oxide (MOx) is endowed by the weakened M-O covalency bonding when meticulously stretching the lattice distance 18,19,20,21,22 . That is the introduction of lattice tensile strain (TS) effectively bypasses the LOM and related negative effects on the crystal integrity, resulting in the improved anti-corrosion ability of RuO 2 acidic OER catalysts. Modifying this new tensile strained RuO 2 (TS-RuO 2 ) with extrinsic metal atoms then evokes the alterations in its intrinsic unfavorable electronic configurations, wherein the careful metal selection could finally achieve the optimization absorption of the intermediates on Ru active sites during the AEM process (Scheme 1a) 23,24,25,26,27,28,29 . Those modulations are highly desired to break the activity-stability trade-off of RuO 2 for acidic water electrooxidation, and no contribution has been proved experimentally or theoretically (Scheme 1b). Herein, the quenching process assisted by the molten salt bath was devised to decorate the homemade ruthenium dioxide (RuO 2-x ) with the relatively apparent and uniform TS (TS-RuO 2-x ), meanwhile maintaining the higher integrity of small nano-sized crystals. Then, homogenously incorporating the trace amounts of strontium (Sr, 4d 7 5s 1 ) and tantalum (Ta, 4f 14 5d 3 6s 2 ) atoms (named TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2-x ) to substitute the Ru (4d 7 5s 1 ) position triggers the optimized electrons redistribution among active sites. Such improved catalytic kinetics were not only reflected by the rather lower overpotential (166 mV at 10 mA cm -2 ) but also the continuous operations on TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2-x during 1000 h with a degradation rate of 0.02 mV/h in 0.5 H 2 SO 4 solution, as well as an order of magnitude higher stability number (S-number, mol O2 /mol Ru-dissolved ) than catalyst without TS (Sr 0.1 Ta 0.1 Ru 0.8 O 2-x ). Comprehensive investigations convinced that TS-induced lower Ru-O covalency contributes to enhancing stability by avoiding the LOM pathways. The electronic modulations originating from dual atom substitution play a primary role in accelerating the OER kinetics. In addition, a two-electrodes device assembled by TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2-x catalyst exhibits ultrastable acidic water electrolysis of 500 and 100 h at current densities of 10 and 50 mA cm -2 . Results and Discussion Synthesis and characterization of the nanocatalysts TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x nanocatalysts were formed in the molten salts (NaCl + NaNO 3 ) at 400 ℃ after preparing the precursor with 1/10 Sr, 1/10 Ta, and 8/10 molar ratio column feed. Due to the repulsion between cationic Na and Ru spreading the nucleation and crystallographic points, such a hot liquid bath allowed the uniform distribution of small-sized nanoparticles with higher crystal phases while eliminating the dopants-induced mutation of RuO 2 − x morphology 22 , 30 . Thereafter, the liquid mixture was immediately quenched in excessive water (about 20 ℃), and crystallographic growth was abruptly stopped. Alkali metal salts therein were instantly and completely dissolved in cool water, which well-preserved the expanded lattice parameters and relaxed Ru-O interaction of high-temperature status, finally the TS was generated in RuO 2 − x catalysts 31 , 32 , 33 . With the sole incorporation of Sr and Ta during a similar process, TS-Sr 0.1 Ru 0.9 O 2−x and TS-Ta 0.1 Ru 0.9 O 2−x were obtained respectively (Fig. S1 ). In contrast, the RuO 2 − x and Sr 0.1 Ta 0.1 Ru 0.8 O 2−x catalysts without TS were prepared via traditional natural cooling and followed a sonication-assisted water washing step. The intact nanoparticulate crystal with uniform 10–20 nm size and dominant (110) facet orientation of all RuO 2 − x catalysts is shown in Transmission electron microscopy (TEM) and High-resolution TEM (HRTEM) images (Fig. 1 a, Figs.S2-S6a,b). High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and corresponding EDS elemental mapping images reflect the atomic homogenous distribution of Sr and Ta elements among bulk phase (Fig. 1 b, Figs. S2-S6c). As observed from the HRTEM images, the average lattice spacing along (110) for RuO 2 − x is 0.314 nm (Fig. 1 c), which is rather close to the 0.315 nm of the theoretical value for commercial RuO 2 (PDF 96-210-1931). The value is increased to 0.328 nm after TS modifications in TS-RuO 2 − x (Fig. S3d) and further 0.33 nm in TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x (Fig. 1 e). Meanwhile, the 0.333 nm and 0.328 nm are also displayed in the TS-Sr 0.1 Ru 0.9 O 2−x (Fig. S4d) and TS-Ta 0.1 Ru 0.9 O 2−x (Fig. S5d) nanocatalysts, respectively, in contrast to 0.318 nm of Sr 0.1 Ta 0.1 Ru 0.8 O 2−x case (Fig. S6d). Serving our RuO 2 − x as the benchmark quantifies the axial TS about 4.5% (TS-RuO 2 − x ), 5.1% (TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x ), 5.1% (TS-Sr 0.1 Ru 0.9 O 2−x ), 4.5% (TS-Ta 0.1 Ru 0.9 O 2−x ), and 1.3% (Sr 0.1 Ta 0.1 Ru 0.8 O 2−x ) along (110) facets (Fig. 1 g). The spatial TS distribution components ( ε xx perpendicular to (110) and ε yy in the (110) plane associated with contraction/expansion of the respective lattice vectors and ε xy shear strain) are mapped by the geometric-phase analysis (GPA) 20 , 22 , 33 . It displays that the values of ε xx , ε xy , and ε yy are nearly zero on the surface of RuO 2 − x (Fig. 1 d), whereas those distinctly increase on tensile strained samples, especially the respective ε yy maximum values of ~ 4.5% and ~ 5% are reached on the TS-RuO 2 − x (Fig. S3e) and TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x (Fig. 1 f), providing the visual evidence of the TS presence in the (110) plane. Lattice expansion also can be indicated by the (110) diffraction peak downshifting compared to those of RuO 2 − x and Sr 0.1 Ta 0.1 Ru 0.8 O 2−x in the X-ray diffraction (XRD) pattern (Fig. 1 h, S7). Electronic structure characterizations To explore the effects of TS and Sr-Ta dual dopants on the electronic structures and chemical states, X-ray photoelectron spectroscopy (XPS) was first carried out and carefully investigated. As shown in Fig. 2a, the M-O L (lattice oxygen) peak in O1s XPS slightly upshifts after TS modifications, but the extrinsic Sr-Ta atoms co-insertion brings significant alterations to the oxygen chemical state in terms of a rather noticeable shifting of the M-O L peak. For TS-Sr 0.1 Ru 0.9 O 2−x and TS-Ta 0.1 Ru 0.9 O 2−x catalysts (Fig. S8a), the sole Sr and Ta atoms substitution gives rise to an opposite change of M-O L peak position due to the large difference between the valent electrons configurations of Sr 2+ and Ta 5+ . Thus, the presence of codoped Sr-Ta may optimize the electronic structure of O sites to some extent, which is favorable for the deprotonation process of *OH intermediate during the OER 34 , 35 , 36 . A similar conclusion also can be obtained from the Ru 3d XPS spectra, in which the electronic and valent modulations of Ru sites primarily are ascribed from the simultaneous Sr and Ta doping rather than the TS presence (Figs. 2b, S8). Convinced that the foreign atoms primarily result in moderate alterations in chemical state and electronic density on Ru sites, ensuring the optimal oxophilicity towards the species during OER 36 , 37 . The ratios of (oxygen vacancy) V O / M-O L and Ru > 4+ /Ru 4+ are summarized in Figs. 2c and 3d, respectively, indicating that the TS gradually alleviates the formation rate of V O and unstable Ru composition, which solids the integrity of crystal RuO 2 − x . While the independently cationic Sr 2+ and Ta 5+ affect those components' ratios dramatically, especially showing the opposite tendency in Sr 2+ and Ta 5+ cases. The balance between (V O )/ M-O L and Ru > 4+ /Ru 4+ occurs as a result of the synergistic interaction between Ru and codoped Sr / Ta atoms, rendering the preferable catalytic ability on both intrinsic O and Ru sites in TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x 38,39 . In addition, the change of Ru valence states and Ru-O bond lengths are revealed by the Ru K-edge X-ray absorption near-edge spectroscopy (XANES) (Figs. 2e, S9a). The absorption edge of our RuO 2 − x shifts to a higher energy position compared with those of references, including RuO 2 (r-RuO 2 ), RuCl 3 (r-RuCl 3 ), and Ru metal (r-Ru), indicating that the average oxidation state of Ru in RuO 2 − x is higher than 4+, which is also consistent with the XPS conclusion about the abundant V O and Ru > 4+ presence. Introducing the lattice TS decreases the valence state reflected by the absorption edge negative shifting of TS-RuO 2 − x . Like the analysis from the XPS, the moderate valence state of Ru can be achieved once co-modulated by the Sr and Ta atoms, while its Ru-K absorption edge is positioned between that of sole Sr and Ta cases (Figs. S9b,c). Those suggest that more favorable electronic redistributions among active sites are facilely triggered by synergetic modulations of atomic Sr 2+ and Ta 5+ (details in supporting information). The extended X-ray absorption fine structure (EXAFS) spectra show a slight stretch of Ru-O bond in all TS samples (Figs. 2f, S9d). Interestingly, a strained effect also stretches the Ru-Ru and Ru-O-M lengths longer compared with those of RuO 2 − x due to TS-induced variation of spatial lattice parameters, possibly corresponding to the strain existence along ε xx , and ε yy directions. Thus, it is predictable that the elongated Ru-O bonding and synergistic electronic interactions among Sr-Ru-Ta units can improve the stability-activity of RuO 2 − x for acidic OER, respectively (Fig S10). Electrocatalytic activity and stability in acidic electrolyte To unravel how the dominant contribution of TS and electronic modulations works in balancing the stability-activity trade-off, the electrocatalytic OER activity was measured with a three-electrode system in 0.5 M H 2 SO 4 , wherein our RuO 2 − x catalysts, Pt wire, and Hg/Hg 2 SO 4 were working, counter, and reference electrode respectively (Fig. S10). The linear sweep voltammetry (LSV) curves of all prepared nanocatalysts are shown in Figs. 3a,b. It can be noticed that TS and co-doped simultaneously improve the OER activity to various degrees. The overpotentials at 10 mA cm − 2 achieved on RuO 2 − x and TS-RuO 2 − x are about 243 mV and 210 mV, close to the most reported values (Supplementary Table S1 ). Whereas only 183 mV and 166 mV overpotentials are required on Sr 0.1 Ta 0.1 Ru 0.8 O 2−x and TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x electrodes, respectively, outperforming the many latest excellent catalysts. Meanwhile, the Tafel slope values are significantly reduced from 154.5 mV dec − 1 of RuO 2 − x to 67.9 mV dec − 1 of Sr 0.1 Ta 0.1 Ru 0.8 O 2−x and 56.6 mV dec − 1 of TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x (Fig. 3c, Figs. S12a,b). Electronic modulation promotion is maximized under the co-presence of Sr and Ta. No distinct changes are observed from LSV curves obtained on the TS-RuO 2 − x , TS-Sr 0.1 Ru 0.9 O 2−x , and TS-Ta 0.1 Ru 0.9 O 2−x electrodes. Moreover, the intrinsic activity of Ru sites was examined by the electrochemically active surface area (ECSA) normalized LSV curves (Fig. S13) 40 , 41 . Figure 3d presents the approximately close ECSA-current densities on Sr 0.1 Ta 0.1 Ru 0.8 O 2−x and TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x with the increase of potentials, and inconspicuous disparity can be noticed between RuO 2 − x and TS-RuO 2 − x . And the emergence of the Sr-Ru-Ta unit enables the optimized intrinsic activity of Ru sites, resulting in the superior ECSA-normalized LSV curves to those of TS-Sr 0.1 Ru 0.9 O 2−x , and TS-Ta 0.1 Ru 0.9 O 2−x (Fig. 3e). Similar phenomena are also reflected by the Ru mass-normalized LSV curves (Figs. S12c,d). These clues demonstrate the fact that the synergy of Sr and Ta electronic modulators primarily contributes to the enhanced activity of Ru sites than TS modification. Keeping strong stability in acidic conditions while achieving outstanding OER activity always remains a great challenge for RuO 2 catalysts. Thus the chronopotentiometry curves (V-T) were first obtained at 10 mA cm − 2 (Fig. 3f). Noticed that without lattice expansion, RuO 2 − x and Sr 0.1 Ta 0.1 Ru 0.8 O 2−x electrodes display acceptable resistance to corrosion within the front 300 h, respectively possessing the decay rate of 0.25 mV/h and 0.39 mV/h. Impressively, a dozen times smaller decay rates are present on the TS-RuO 2 − x (0.03 mV/h) and TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x (0.02 mV/h) even during the continuous operation up to 1000 h. These illustrate that due to the decreased Ru-O covalency, the TS majorly functions on efficiently strengthening the RuO 2 − x nanocrystal integrity and avoiding the LOM pathway 19 , 42 . The stability superiority of TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x also can be evidenced by the more harsh electrocatalysis (200 mA cm − 2 within 200 h) (Fig. 3g) and careful comparisons of overpotential at 10 mA cm − 2 -measured stability period with abundant references catalysts (Fig. 3h, Supplementary Table S1 ). The homemade water electrolyzer was assembled by TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x (cathode) and commercial Pt/C (anode), delivering the 10 mA cm − 2 and 50 mAcm − 2 only at 1.45 V and 1.53 V in 0.5 M H 2 SO 4 , respectively, much lower than 1.55 V and 1.78 V of commercial RuO 2 (c-RuO 2 ) and Pt/C benchmark (Fig. 3i). Thanks to the merits of TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x , our water electrolyzer can sustainably work over 500 h and 100 h at 10 mA cm − 2 and 50 mAcm − 2 without apparent degradation, presenting the promising potential for large-power applications (Figs. 3j and k). Origin of improved stability Understanding which reaction pathway dominates is the premise before clarifying the origin of enhanced performance. Since the non-concerted proton-electron transfer step causes the typical pH-dependent OER behavior for the LOM mechanism, pH-dependent activity was measured on all catalysts (Fig. S14) 43 . As shown in Figs. 4a and b, pH-dependent phenomena of RuO 2 − x are reversed after TS introduction due to the slopes of pH-overpotentials (5, 10, 20 mA cm − 2 ) tending to be parallel, and the same feature also can be found in other strained catalysts (Fig. S14). This confirms that the lattice oxygen release was significantly alleviated to enable higher stability due to the TS presence. Isotopic oxygen ( 18 O) labeling experiments were further conducted in well-closed two-separated chamber cells to certify the suppressed LOM process induced by TS (Fig. S15) 42 , 44 . The gas products at the constant current density and period were collected to analyze in gas chromatography-mass spectrometry (GC-MS) (Fig. 4c, Figs. S16, S17). Noticed that the O 2 ( 18 O 16 O) relative intensity on c-RuO 2 , RuO 2 − x , and Sr 0.1 Ta 0.1 Ru 0.8 O 2−x surface achieve 3.9%, 2.9%, and 1.7%, while the TS-RuO 2 − x and TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x is reduced to 0.6% and 0.4%, respectively (Fig. 4d). These clues unambiguously corroborate the less participation of lattice oxygen on strained samples, enabling these prefer to the AEM mechanism. Thereafter, the in-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) was conducted to validate the exclusive AEM process (Fig. S18). As shown in Fig. 4e, an absorption band (~ 1142 cm − 1 ) corresponding to the key water oxidation intermediate *OOH (AEM) can be observed and its intensity starts to gradually increase as the the potential is higher than 1.3 V 45 . An isotopic shift when the solvent is switched from H 2 O to D 2 O indicates that the vibrational mode of the species involves hydrogen 46 , excluding the direct O-O intramolecular coupling pathway and further verifying the AEM process (Fig. 4f) 47 . It is noteworthy that TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x displays rather higher vibration bands (*OOH and *OOD) intensity compared to those of RuO 2 − x and TS-RuO 2 − x (Figs. 4g, S18b), indicating that the Sr and Ta incorporation greatly promotes the rate-determined reaction step of acidic OER. Due to the AEM predominance, the Ru dissolution rate from TS-RuO 2 − x and TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x catalysts can be efficiently alleviated, as reflected by the ICP-OES measurements results (Figs. 5 a, S19a). Lattice expansion preserves the Ru atoms from corrosion, and dissolved Ru ions tend to a constant value after 50 min, in sharp contrast to the samples without TS. This promotion also can be demonstrated by that an order of magnitude higher S-number is achieved on TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x (Figs. 5 b, S19b-S19e) 9 , 48 . Thus, acceptable alterations of chemical state and constituents emerge on the strained catalysts' surface even after 3000 CV cycles (Fig. S20, Supplementary Table S2). A rather higher portion of O L remains in O 1s XPS of post-TS-RuO 2 − x and post-TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x catalysts, whereas almost all O L depletion in cases of post-RuO 2 − x and post-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x (Figs. 5 c, S20a). Likewise, in Ru 3d XPS spectra of post-reaction samples, a slight increase of Ru > 4+ /Ru 4+ ratio is observed after the reaction due to the TS presence (Figs. 5 d, S20b), corresponding to the higher valence state observed in XANES. Those are in stark contrast to the 100% Ru > 4+ species that remained on the surface of post-RuO 2 − x and post-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x . In addition, the rigidity of lattice TS itself is also praiseworthy, reflected by the unchanged bonding of Ru-O and Ru-O-M in EXAFS (Fig. S21), as well as the stable d-spacing distance (110) and positive strain component values of GPA (Figs. 5 e, 5 f, and Fig. S22). Origin of enhanced activity Once the AEM mechanism is confirmed, the OER activity is mainly controlled by the key species transfer behavior. In-situ electrochemical impedance spectroscopy (in-situ EIS) was measured from programmed 1.0 V to 1.5 V (vs. RHE) within the 10 2 -10 5 Hz frequency range in 0.5 M H 2 SO 4 (Figs. 6a, S23, and S24). Corresponding equivalent circuit models show three tandem components, wherein the Rs represent solution resistance, and the other two tandem components respectively reflect the charge-transfer kinetics in electrical double-layer (Q 1 /R 1 ) and intermediates transfer among the active site (Q 2 /R 2 ) (Fig. 6b) 49 , 50 . Then related species transfer numbers and related resistance were carefully simulated (Supplementary Tables S3-S9, Fig. S25). It is noteworthy that the lowest Q 1 values of RuO 2 − x are increased after Sr and Ta co-presence and the R 1 on these two samples tends to approximate as the potential reaches about 1.35 V (close to OER onset potentials) (Fig. 6c). Meanwhile, the TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x is featured by the much higher Q 1 and lower R 1 , manifesting the enlarged active surface area and facilitated charge transfer mainly induced by the electronic modulators. Thus, the almost same Q 2 and relatively similar R 2 values are present on the co-doped catalyst surface (Fig. 6d). The Bode plot demonstrates that the 1.4 V onset potential of RuO 2 − x (Fig. S23d) is reduced to 1.35 V of TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x (Figs. 6e, S24h). Unlike the electrode evolution process undergone by c-RuO 2 (Fig. S23b), associated peaks are absent in high-frequency regions in our catalysts, providing veritable catalytic phases 51 . Also noticed that only a negligible difference in phase angle peaks at 1.5 V is found after TS modification, whereas Sr and Ta introduction results in the rather lower phase angle peaks, especially the 10.051 θ and 9.557 θ observed on Sr 0.1 Ta 0.1 Ru 0.8 O 2−x and TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x (Fig. 6e). Those indicate that TS weakly contributes to the facilitated migration kinetics of active species on Ru and O sites, but the Sr-Ru-Ta unit significantly does. Theoretical investigation After building the configurations including RuO 2 , TS-RuO 2 (5% TS), Sr 0.1 Ta 0.1 Ru 0.8 O 2 , and TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2 (5% TS) to represent corresponding experiments models (Figs. S26a-d), density functional theory (DFT) calculations were carefully conducted. It reveals that the energy barrier of Vo formation and OER pathway can be primarily tuned fluctuation of ε p and ε d (d band center). This synergy prefers to optimize the absorption ability of active sites since too weak or too strong affinity for oxygen and proton intermediates can be avoided. Like conclusions from experiments, the electronic structural alterations are induced by the co-doping effect more efficiently 23 . Then both AEM and LOM free energy of OER coordinates was calculated (Figs. S27-S35). The theoretical overpotentials (η) at U = 1.23 V of LOM and AEM on RuO 2 − x surface are respective 1.95 eV and 0.8 eV (Fig. 6g). As high as η = 2.19 eV is required for the LOM pathway on the TS-modified model, certifying that the TS mainly constrains the LOM participation during OER (Fig. S27a). Extrinsic Sr and Ta modulators accelerate AEM and LOM kinetics simultaneously due to the respectively smaller η = 1.61 eV and η = 0.56 eV, which may result in the instability of Sr 0.1 Ta 0.1 Ru 0.8 O 2−x (Fig. S27b), whereas LOM of η = 2.08 eV and AEM of η = 0.52 eV are concurrent (Fig. 6h). It is noteworthy that only suitable movement of ε p and ε d finally minimizes the AEM energy barrier through making the simultaneous improvement of deprotonation on O and key intermediates sorption on Ru sites (Fig. 6i) 52 . These results jointly support the fact that a balanced stability-activity trade-off is experimentally achieved on our TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x . Conclusions In summary, tensile strained Sr 0.1 Ta 0.1 Ru 0.8 O 2−x nanocatalysts were prepared through the molten salt assistant quench process. The TS along the nanocrystalline phases (110) stretches the Ru-O bond lengths and weakens the covalency, thereby avoiding the LOM pathway by making V O formation more difficult and enhancing long-term durability. Furthermore, the synergic functionality of Sr and Ta dopants has been proven to optimize the electronic configuration, favoring the adsorption-desorption of intermediates on Ru/O sites and lowering the energy barriers for OER. Thus, our TS-Sr 0.1 Ta 0.1 Ru 0.8 O 2−x electrode demonstrates outstanding stability while outperforming most reported acidic OER activities, as evidenced by comprehensive experimental and theoretical characterizations. This work not only unravels the respective contribution of TS and doping effect but also showcases an elaborate design of outstanding catalysts with strengthened stability toward OER. Declarations Data availability The authors declare that all data supporting the findings of this study are available from the corresponding author upon request. Acknowledgments This work was supported by the National Research Foundation of Korea (NRF) grant (NRF-2022R1A2C2093415) and the Qilu Young Scholars Program of Shandong University (China). The authors thank the BL10C beamline of the Pohang Light Source (PLS-II, Korea) Facility for providing synchrotron beam time. Author contributions Y. L. designed all experimental schemes, conceptualization, and writing drafts. Y. L. and Y. W. carried out the experiments together. H. L. achieved the DFT calculations. M. G. K. conducted the XAS experiments and analysis. M. W. and H. L. gave the direction, supervision, and editing of this draft. Competing interests The authors declare no competing financial interest. Additional Information Supporting information The online version contains supplementary information available at References Chu S, Majumdar A (2012) Opportunities and challenges for a sustainable energy future. Nature 488:294–303 Li A et al (2024) Atomically dispersed hexavalent iridium oxide from MnO 2 reduction for oxygen evolution catalysis. Science 384:666–670 Wang Z, Zheng Y-R, Chorkendorff I, Nørskov JK (2020) Acid-Stable Oxides for Oxygen Electrocatalysis. ACS Energy Lett 5:2905–2908 An L et al (2021) Recent Development of Oxygen Evolution Electrocatalysts in Acidic Environment. Adv Mater 33:e2006328 Grimaud A et al (2016) Activation of surface oxygen sites on an iridium-based model catalyst for the oxygen evolution reaction. Nat Energy 2 Elmaalouf M et al (2021) The origin of the high electrochemical activity of pseudo-amorphous iridium oxides. Nat Commun 12:3935 Fan Z et al (2021) Extraordinary acidic oxygen evolution on new phase 3R-iridium oxide. Joule 5:3221–3234 Lyons ME, Floquet S (2011) Mechanism of oxygen reactions at porous oxide electrodes. Part 2–Oxygen evolution at RuO 2 , IrO 2, and Ir x Ru 1-x O 2 electrodes in aqueous acid and alkaline solution. Phys Chem Chem Phys 13:5314–5335 Scott SB et al (2022) The low overpotential regime of acidic water oxidation part II: trends in metal and oxygen stability numbers. Energy Environ Sci 15:1988–2001 Gao J, Tao H, Liu B (2021) Progress of Nonprecious-Metal-Based Electrocatalysts for Oxygen Evolution in Acidic Media. Adv Mater 33:e2003786 Li S et al (2024) Exploring the potential Ru-based catalysts for commercial-scale polymer electrolyte membrane water electrolysis: A systematic review. Prog Mater Sci 145:101294 Song J et al (2020) A review on fundamentals for designing oxygen evolution electrocatalysts. Chem Soc Rev 49:2196–2214 Grimaud A et al (2017) Activating lattice oxygen redox reactions in metal oxides to catalyse oxygen evolution. Nat Chem 9:457–465 Jin H et al (2023) Dynamic rhenium dopant boosts ruthenium oxide for durable oxygen evolution. Nat Commun 14:354 Kuznetsov DA, Naeem MA, Kumar PV, Abdala PM, Fedorov A, Muller CR (2020) Tailoring Lattice Oxygen Binding in Ruthenium Pyrochlores to Enhance Oxygen Evolution Activity. J Am Chem Soc 142:7883–7888 Pan Y et al (2020) Direct evidence of boosted oxygen evolution over perovskite by enhanced lattice oxygen participation. Nat Commun 11:2002 Wang Q et al (2023) Long-Term Stability Challenges and Opportunities in Acidic Oxygen Evolution Electrocatalysis. Angew Chem Int Ed Engl 62:e202216645 Li L et al (2024) Lanthanide-regulating Ru-O covalency optimizes acidic oxygen evolution electrocatalysis. Nat Commun 15:4974 Ping X et al (2024) Locking the lattice oxygen in RuO 2 to stabilize highly active Ru sites in acidic water oxidation. Nat Commun 15:2501 Qin Y et al (2022) RuO 2 electronic structure and lattice strain dual engineering for enhanced acidic oxygen evolution reaction performance. Nat Commun 13:3784 Yagi S et al (2015) Covalency-reinforced oxygen evolution reaction catalyst. Nat Commun 6:8249 Hao S et al (2021) Torsion-strained iridium oxide for efficient acidic water oxidation in proton exchange membrane electrolyzers. Nat Nanotechnol 16:1371–1377 Hao S et al (2020) Dopants fixation of Ruthenium for boosting acidic oxygen evolution stability and activity. Nat Commun 11:5368 He J, Li W, Xu P, Sun J (2021) Tuning electron correlations of RuO 2 by co-doping of Mo and Ce for boosting electrocatalytic water oxidation in acidic media. Appl Catal B 298:120528 Joo J et al (2022) Mn-Dopant Differentiating the Ru and Ir Oxidation States in Catalytic Oxides Toward Durable Oxygen Evolution Reaction in Acidic Electrolyte. Small Methods 6:e2101236 Sun W, Song Y, Gong XQ, Cao LM, Yang J (2015) An efficiently tuned d-orbital occupation of IrO 2 by doping with Cu for enhancing the oxygen evolution reaction activity. Chem Sci 6:4993–4999 Wang J et al (2022) Single-site Pt-doped RuO 2 hollow nanospheres with interstitial C for high-performance acidic overall water splitting. Sci Adv 8:eabl9271 Wu ZY et al (2023) Non-iridium-based electrocatalyst for durable acidic oxygen evolution reaction in proton exchange membrane water electrolysis. Nat Mater 22:100–108 Zhang D et al (2023) Construction of Zn-doped RuO 2 nanowires for efficient and stable water oxidation in acidic media. Nat Commun 14:2517 Gupta SK, Mao Y (2021) A review on molten salt synthesis of metal oxide nanomaterials: Status, opportunity, and challenge. Prog Mater Sci 117:100734 Liu T, Yang S, Guan J, Niu J, Zhang Z, Wang F (2022) Quenching as a Route to Defect-Rich Ru-Pyrochlore Electrocatalysts toward the Oxygen Evolution Reaction. Small Methods 6:e2101156 Ye C et al (2021) Activating Metal Oxides Nanocatalysts for Electrocatalytic Water Oxidation by Quenching-Induced Near-Surface Metal Atom Functionality. J Am Chem Soc 143:14169–14177 Kumar A et al (2021) Discovering ultrahigh loading of single-metal-atoms via surface tensile-strain for unprecedented urea electrolysis. Energy Environ Sci 14:6494–6505 Deng L et al (2023) Valence Oscillation of Ru Active Sites for Efficient and Robust Acidic Water Oxidation. Adv Mater 35:e2305939 Huang K et al (2022) Ru/Se-RuO 2 Composites via Controlled Selenization Strategy for Enhanced Acidic Oxygen Evolution. Adv Funct Mater 33 Lee K et al (2023) Modulating the valence electronic structure using earth-abundant aluminum for high-performance acidic oxygen evolution reaction. Chem 9:3600–3612 Han N et al (2024) Lowering the kinetic barrier via enhancing electrophilicity of surface oxygen to boost acidic oxygen evolution reaction. Matter 7:1330–1343 Wen Y et al (2022) Introducing Bronsted acid sites to accelerate the bridging-oxygen-assisted deprotonation in acidic water oxidation. Nat Commun 13:4871 Wu Q et al (2024) Boosting electrocatalytic performance via electronic structure regulation for acidic oxygen evolution. iScience 27:108738 Liu Y et al (2024) Insight into Controllable Metal-Support Interactions in Metal/Metal Electrocatalysts for Efficient Energy-Saving Hydrogen Production. ACS Nano 18:874–884 Hao J et al (2022) Unraveling the electronegativity-dominated intermediate adsorption on high-entropy alloy electrocatalysts. Nat Commun 13:2662 Wen Y et al (2021) Stabilizing Highly Active Ru Sites by Suppressing Lattice Oxygen Participation in Acidic Water Oxidation. J Am Chem Soc 143:6482–6490 Giordano L et al (2016) pH dependence of OER activity of oxides: Current and future perspectives. Catal Today 262:2–10 Zhang N et al (2020) Lattice oxygen activation enabled by high-valence metal sites for enhanced water oxidation. Nat Commun 11:4066 Su H et al (2021) In-situ spectroscopic observation of dynamic-coupling oxygen on atomically dispersed iridium electrocatalyst for acidic water oxidation. Nat Commun 12:6118 Park K, Kim Y, Lee KJ (2019) Analysis of deuterated water contents using FTIR bending motion. J Radioanal Nucl Chem 322:487–493 Zhu W et al (2023) Direct Dioxygen Radical Coupling Driven by Octahedral Ruthenium-Oxygen-Cobalt Collaborative Coordination for Acidic Oxygen Evolution Reaction. J Am Chem Soc 145:17995–18006 Geiger S et al (2018) The stability number as a metric for electrocatalyst stability benchmarking. Nat Catal 1:508–515 Liu Y et al (2022) Unveiling the Protonation Kinetics-Dependent Selectivity in Nitrogen Electroreduction: Achieving 75.05% Selectivity. Angew Chem Int Ed Engl 61:e202209555 Lu Y et al (2022) Tailoring Competitive Adsorption Sites by Oxygen-Vacancy on Cobalt Oxides to Enhance the Electrooxidation of Biomass. Adv Mater 34:e2107185 Gu K et al (2021) Defect-Rich High-Entropy Oxide Nanosheets for Efficient 5-Hydroxymethylfurfural Electrooxidation. Angew Chem Int Ed Engl 60:20253–20258 Shi Z et al (2023) Customized reaction route for ruthenium oxide towards stabilized water oxidation in high-performance PEM electrolyzers. Nat Commun 14:843 Schemes Scheme 1 is available in the Supplementary Files section Additional Declarations There is NO Competing Interest. Supplementary Files Scheme1.docx Supplementaryinformation.docx Cite Share Download PDF Status: Published Journal Publication published 17 Feb, 2025 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4721957","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":333905234,"identity":"a7ec237d-6726-4651-807c-51d072b81492","order_by":0,"name":"Hyoyoung Lee","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAwklEQVRIiWNgGAWjYBACAxiDn4GNGUQzNhCtRbKBZC0GB4jVYi6RfEziY9sdu83njyUb8zDYyG44QECL5Yy0NMmZbc+St91IO5zMw5BmTFCLwY0cM2netsPJZjfYmw/zMBxOJF6Lcf9xkJb/xGuxM2AAO+wAEVrOPEu2nHHucILEjbRkwzkGycYzCWo5nnzwxoeyw/b8/ceMJd5U2Mn2EdLCIJDAIgGkEhsgJhBSDgL8B5g/ACl7YtSOglEwCkbBCAUAkvBGnW6c+REAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-8031-0791","institution":"Sungkyunkwan University","correspondingAuthor":true,"prefix":"","firstName":"Hyoyoung","middleName":"","lastName":"Lee","suffix":""},{"id":333905235,"identity":"a81fa929-ec40-45da-9cd9-cef831e82770","order_by":1,"name":"Yang Liu","email":"","orcid":"","institution":"Shandong University","correspondingAuthor":false,"prefix":"","firstName":"Yang","middleName":"","lastName":"Liu","suffix":""},{"id":333905236,"identity":"860cb48a-c3da-4fe9-9a95-85c8d1acbf4e","order_by":2,"name":"Yixuan Wang","email":"","orcid":"https://orcid.org/0009-0003-3235-6538","institution":"Sungkyunkwan University","correspondingAuthor":false,"prefix":"","firstName":"Yixuan","middleName":"","lastName":"Wang","suffix":""},{"id":333905237,"identity":"32720262-ecbe-4460-a166-d865143e7a86","order_by":3,"name":"Hao Li","email":"","orcid":"","institution":"SungKyunKwan University","correspondingAuthor":false,"prefix":"","firstName":"Hao","middleName":"","lastName":"Li","suffix":""},{"id":333905238,"identity":"90f21fc5-f083-4993-a9bb-18c211b2efc4","order_by":4,"name":"Min Kim","email":"","orcid":"https://orcid.org/0000-0002-2366-6898","institution":"Pohang Accelerator Laboratory","correspondingAuthor":false,"prefix":"","firstName":"Min","middleName":"","lastName":"Kim","suffix":""},{"id":333905239,"identity":"dd1e086f-7351-4edf-943c-41484adce509","order_by":5,"name":"Mingbo Wu","email":"","orcid":"https://orcid.org/0000-0003-0048-778X","institution":"China University of Petroleum","correspondingAuthor":false,"prefix":"","firstName":"Mingbo","middleName":"","lastName":"Wu","suffix":""}],"badges":[],"createdAt":"2024-07-11 05:40:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4721957/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4721957/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41467-025-56638-8","type":"published","date":"2025-02-17T05:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":61545822,"identity":"2514cbb3-d060-44ab-b095-ce60f07115f7","added_by":"auto","created_at":"2024-08-01 04:49:48","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":871195,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMicrostructure and tensile strain analysis. a\u003c/strong\u003e HRTEM image, \u003cstrong\u003eb\u003c/strong\u003e HAADF-STEM image, and corresponding EDS elemental mapping of TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e sample. \u003cstrong\u003ec,e\u003c/strong\u003e Rendered HRTEM image of RuO\u003csub\u003e2-x\u003c/sub\u003e and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e, respectively, insets are selected area electron diffraction (SEAD) patterns (110 facets), below \u003cstrong\u003ec\u003c/strong\u003e and \u003cstrong\u003ee\u003c/strong\u003e are corresponding intensity profiles along the white line.\u003cstrong\u003e d,f \u003c/strong\u003eGPA contour map of the strain components ε\u003csub\u003exx\u003c/sub\u003e, ε\u003csub\u003exy\u003c/sub\u003e, and ε\u003csub\u003eyy\u003c/sub\u003e relative to the RuO\u003csub\u003e2-x\u003c/sub\u003e reference values on the surface of RuO\u003csub\u003e2-x\u003c/sub\u003e and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e, \u003cstrong\u003eg,h\u003c/strong\u003e Summary of tensile strain values and XRD patterns with local magnificent (110) peak of all catalysts.\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-4721957/v1/67e26ed22e5856e95d283656.png"},{"id":61545824,"identity":"33766244-f1d9-4f68-a65d-1c4391d02f75","added_by":"auto","created_at":"2024-08-01 04:49:48","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":840282,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eElectronic and bonding structure characterizations. a,b \u003c/strong\u003eO1s and Ru 3d XPS spectra, and \u003cstrong\u003e(c,d) \u003c/strong\u003ethe summary of V\u003csub\u003eO\u003c/sub\u003e/V\u003csub\u003eM-OL\u003c/sub\u003e and Ru\u003csup\u003e\u0026gt;4+\u003c/sup\u003e/Ru\u003csup\u003e+4 \u003c/sup\u003eratios on the surface of RuO\u003csub\u003e2-x\u003c/sub\u003e, TS-RuO\u003csub\u003e2-x\u003c/sub\u003e, Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e, and, TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e catalysts. The Ru K-edge XANES \u003cstrong\u003e(e) \u003c/strong\u003eand EXAFS spectra \u003cstrong\u003e(f) \u003c/strong\u003eof RuO\u003csub\u003e2-x\u003c/sub\u003e, TS-RuO\u003csub\u003e2-x\u003c/sub\u003e, Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e, and, TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e catalysts with those of r-Ru, r-RuCl\u003csub\u003e3\u003c/sub\u003e, and, r-RuO\u003csub\u003e2\u003c/sub\u003e references, showing the vibration of Ru valence states on doped samples and elongated Ru-O bonding in strained samples.\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-4721957/v1/7c89164862a5f64b3f2c6271.png"},{"id":61546311,"identity":"5dc955a3-3700-4955-845e-34fd89b13782","added_by":"auto","created_at":"2024-08-01 04:57:48","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":628410,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eElectrocatalytic activity and stability measurements. a,b \u003c/strong\u003eGeometry-normalized LSV curves, \u003cstrong\u003e(c) \u003c/strong\u003ecomparison of overpotentials at 10 mA cm\u003csup\u003e-2\u003c/sup\u003e together with the Tafel plots, \u003cstrong\u003e(d,e) \u003c/strong\u003eECSA-normalized LSV curves of all strained and doped RuO\u003csub\u003e2-x\u003c/sub\u003e electrocatalysts. \u003cstrong\u003ef\u003c/strong\u003e The chronopotentiometric curves at 10 mA cm-2 measured on RuO\u003csub\u003e2-x\u003c/sub\u003e, TS-RuO\u003csub\u003e2-x\u003c/sub\u003e, Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e, and, TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e catalysts in 0.5 M H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e electrolyte up to 1000 h.\u003cstrong\u003e g \u003c/strong\u003eThe chronopotentiometric curves of TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e electrode obtained at 200 mA cm\u003csup\u003e-2\u003c/sup\u003e over 200 h. \u003cstrong\u003eh\u003c/strong\u003e Comparison of measured stability time-overpotential at 10 mA cm\u003csup\u003e-2 \u003c/sup\u003eamong our and reported catalysts.\u003cstrong\u003e i \u003c/strong\u003eLSV curves of two electrode water electrolyzer employing prepared TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x \u003c/sub\u003ewith the commercial catalysts benchmark. The chronopotentiometric curves of TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x \u003c/sub\u003e//Pt/C electrodes couple at 50 mA cm\u003csup\u003e-2\u003c/sup\u003e within 100 h \u003cstrong\u003e(j)\u003c/strong\u003e and 10 mA cm\u003csup\u003e-2\u003c/sup\u003e within 500 h \u003cstrong\u003e(k) \u003c/strong\u003ein 0.5 M H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e, inset k is the photo of coating catalysts on carbon paper (CP) and Pt/Ti GDL.\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-4721957/v1/04e43ee93a68c19e6b133a1f.png"},{"id":61545821,"identity":"3146d87f-c8dd-4511-b916-f2cef1cec481","added_by":"auto","created_at":"2024-08-01 04:49:48","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":811261,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eOER mechanism identification. a,b \u003c/strong\u003eGeometry-normalized LSV curves of RuO\u003csub\u003e2-x\u003c/sub\u003e and TS-RuO\u003csub\u003e2-x\u003c/sub\u003e in various pH-H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e electrolytes, insets are the corresponding curves of overpotentials-dependent pH values at 5, 10, 20 mA cm\u003csup\u003e-2\u003c/sup\u003e, respectively, suggesting the lowered possibility of LOM pathway. \u003cstrong\u003ec\u003c/strong\u003e The GC and MS spectra measured on GC-MS equipment of collected gas on TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e electrode, showing the different intensity of \u003csup\u003e34\u003c/sup\u003eO\u003csub\u003e2\u003c/sub\u003e (\u003csup\u003e18\u003c/sup\u003eO\u003csup\u003e16\u003c/sup\u003eO) and \u003csup\u003e36\u003c/sup\u003eO\u003csub\u003e2\u003c/sub\u003e (\u003csup\u003e18\u003c/sup\u003eO\u003csup\u003e18\u003c/sup\u003eO) but similar \u003csup\u003e32\u003c/sup\u003eO\u003csub\u003e2\u003c/sub\u003e (\u003csup\u003e16\u003c/sup\u003eO\u003csup\u003e16\u003c/sup\u003eO) signals. . \u003cstrong\u003ed\u003c/strong\u003e Relatively intensity comparison of \u003csup\u003e32\u003c/sup\u003eO\u003csub\u003e2\u003c/sub\u003e (\u003csup\u003e16\u003c/sup\u003eO\u003csup\u003e16\u003c/sup\u003eO), \u003csup\u003e34\u003c/sup\u003eO\u003csub\u003e2\u003c/sub\u003e (\u003csup\u003e18\u003c/sup\u003eO\u003csup\u003e16\u003c/sup\u003eO), and \u003csup\u003e36\u003c/sup\u003eO\u003csub\u003e2\u003c/sub\u003e (\u003csup\u003e18\u003c/sup\u003eO\u003csup\u003e18\u003c/sup\u003eO) signals detected on all prepared RuO\u003csub\u003e2-x\u003c/sub\u003e electrode under same conditions. \u003cstrong\u003ee\u003c/strong\u003e In-situ ATR-SEIRAS spectra measured on TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e electrode in H\u003csub\u003e2\u003c/sub\u003eO-based electrolyte from open circuit potential to 1.6 V (vs. RHE). \u003cstrong\u003ef \u003c/strong\u003eIn-situ ATR-SEIRAS spectra shift when substituting the H\u003csub\u003e2\u003c/sub\u003eO with D\u003csub\u003e2\u003c/sub\u003eO, indicating the proton effect and confirming the AEM mechanism. \u003cstrong\u003eg\u003c/strong\u003e In-situ ATR-SEIRAS absorption intensity comparasion of *OOH intermediates on RuO\u003csub\u003e2-x\u003c/sub\u003e, TS-RuO\u003csub\u003e2-x\u003c/sub\u003e, and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e electrodes in H\u003csub\u003e2\u003c/sub\u003eO based electrolyte.\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-4721957/v1/cf6d65ef2cb09bf559525509.png"},{"id":61546551,"identity":"725555fc-8e87-4f22-bbc2-903890812879","added_by":"auto","created_at":"2024-08-01 05:05:48","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1068473,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStability of physical and chemical structure. a\u003c/strong\u003e The ICP-OES measured dissolved concentration curves of Ru from Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e with and without strain working electrodes, suggesting the enhanced stability induced by the lattice strain. \u003cstrong\u003eb\u003c/strong\u003e S-number of TS-RuO\u003csub\u003e2-x\u003c/sub\u003e, Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e, and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x \u003c/sub\u003ecalculated based on the produced oxygen gas and leached Ru, proving the higher anti-corrosion ability of strained catalysts.\u003cstrong\u003e c,d \u003c/strong\u003eO1s and Ru 3d XPS spectra of Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u0026nbsp; \u003c/sub\u003esamples before and after 3000 CV cycling reaction. \u003cstrong\u003e(e)\u003c/strong\u003e Rendered HRTEM image, inset is selected area electron diffraction (SEAD) patterns (110 facet), below is intensity profiles along white line and \u003cstrong\u003e(f)\u003c/strong\u003e GPA contour map of the strain components ε\u003csub\u003exx\u003c/sub\u003e, ε\u003csub\u003exy\u003c/sub\u003e, and ε\u003csub\u003eyy\u003c/sub\u003e relative to the RuO\u003csub\u003e2-x\u003c/sub\u003e reference values on the surface of post-TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e.\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-4721957/v1/24948b4d603e6d32c8350634.png"},{"id":61545827,"identity":"24ab2723-a034-402b-91f0-42dedbf302ab","added_by":"auto","created_at":"2024-08-01 04:49:48","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":851831,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eExperimental study for the origin of enhanced activity and Theoretical investigation of balanced activity-stability. a\u003c/strong\u003e In-situ EIS spectra measured on TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x \u003c/sub\u003eelectrode from 1.0 to 1.5 V (vs. RHE) with 50 mV amplitude in 0.5 M H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e. \u003cstrong\u003eb\u003c/strong\u003e Diagram of simulated equivalent circuit models R\u003csub\u003eS\u003c/sub\u003e(Q\u003csub\u003e1\u003c/sub\u003eR\u003csub\u003e1\u003c/sub\u003e)(Q\u003csub\u003e2\u003c/sub\u003eR\u003csub\u003e2\u003c/sub\u003e). Simulated Q\u003csub\u003e1\u003c/sub\u003eR\u003csub\u003e1 \u003c/sub\u003e\u003cstrong\u003e(c) \u003c/strong\u003eand Q\u003csub\u003e2\u003c/sub\u003eR\u003csub\u003e2\u003c/sub\u003e \u003cstrong\u003e(d) \u003c/strong\u003evalues of TS-RuO\u003csub\u003e2-x\u003c/sub\u003e, Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e, and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x \u003c/sub\u003ecatalysts. \u003cstrong\u003ee\u003c/strong\u003e Bode plots of c-RuO\u003csub\u003e2\u003c/sub\u003e, RuO\u003csub\u003e2-x\u003c/sub\u003e, TS-RuO\u003csub\u003e2-x\u003c/sub\u003e, Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e, and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x \u003c/sub\u003ecatalysts.\u003cstrong\u003e f \u003c/strong\u003eDOS of RuO\u003csub\u003e2-x\u003c/sub\u003e compared with after-strain or doping models. Calculated AEM mechanism energy barrier diagrams on RuO\u003csub\u003e2-x\u003c/sub\u003e \u003cstrong\u003e(g) \u003c/strong\u003eand TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x \u003c/sub\u003e\u003cstrong\u003e(f) \u003c/strong\u003econfigurations.\u003cstrong\u003e i \u003c/strong\u003eTwo-dimensional contour map shows the restrictive relation of synergetic ε\u003csub\u003ep\u003c/sub\u003e and ε\u003csub\u003ed \u003c/sub\u003eon final AEM overpotential.\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-4721957/v1/5b0c03b435842967371f879f.png"},{"id":76538151,"identity":"2306b7e3-4762-4370-b33c-6835c75a27b4","added_by":"auto","created_at":"2025-02-18 08:07:19","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5649416,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4721957/v1/73fa9169-1e6b-4654-a7ca-063568b5e99e.pdf"},{"id":61545823,"identity":"27d6fe36-5a53-49fe-9220-b8cf8494986b","added_by":"auto","created_at":"2024-08-01 04:49:48","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1076623,"visible":true,"origin":"","legend":"","description":"","filename":"Scheme1.docx","url":"https://assets-eu.researchsquare.com/files/rs-4721957/v1/8080bcd90910bece45b06f55.docx"},{"id":61545828,"identity":"8e687935-6502-411a-b6ec-318185f6100a","added_by":"auto","created_at":"2024-08-01 04:49:48","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":34686305,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementaryinformation.docx","url":"https://assets-eu.researchsquare.com/files/rs-4721957/v1/1c72eea3d5ae68fc9485e877.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"\u003cp\u003eEffectiveness of strain and dopants on breaking the activity-stability trade-off of RuO\u003csub\u003e2\u003c/sub\u003e acidic oxygen evolution electrocatalysts\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eProton Exchange Membrane Water Electrolyzers (PEMWE) offer significant advantages, including low operating temperatures, high voltage efficiency, high current densities, and excellent compatibility, rendering them a promising green hydrogen production technology with substantial development potential\u003csup\u003e1,2,3\u003c/sup\u003e. However, the sluggish reaction kinetics of anodic oxygen evolution reaction (OER) in PEMWE often demand increased energy consumption, significantly reducing operational efficiency and impeding its widespread adoption. Iridium oxide (IrO\u003csub\u003e2\u003c/sub\u003e) remains the sole commercially viable anodic catalyst for PEMWE due to its promising anti-corrosive quality in acidic conditions. Unfortunately, the scarcity and high cost of iridium severely limit the large-scale implementation of PEMWE\u003csup\u003e3,4,5,6,7\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eRuthenium dioxide (RuO\u003csub\u003e2\u003c/sub\u003e) has emerged as a potential alternative catalyst for acidic OER due to its relatively higher intrinsic activity and rather lower cost (about 17% price of Ir metal)\u003csup\u003e3,8\u003c/sup\u003e. Nonetheless, unsatisfied activity and even more serious degradation achieved on RuO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003ein acidic OER conditions still restrict its further consideration for commercial application\u003csup\u003e4,8,9,10,11,12\u003c/sup\u003e. Therefore, understanding the origin behind those present phenomena is the prerequisite for simultaneously improving the activity and stability of RuO\u003csub\u003e2\u003c/sub\u003e catalysts.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn principle, once the OER on RuO\u003csub\u003e2\u003c/sub\u003e mainly follows\u003csub\u003e\u0026nbsp;\u003c/sub\u003ethe adsorbate evolution mechanism (AEM). Overcoming the scaling relation of the adsorption energies between *OH and *OOH key intermediates is crucial, and it can always be realized by the foreign atom\u0026apos;s modulations towards the enhanced activity eventually. The lattice oxygen-mediated mechanism (LOM) leads to the formation of numerous oxygen vacancies (V\u003csub\u003eO\u003c/sub\u003e) and induced over-oxidized Ru species (Ru\u003csup\u003ex\u0026gt;4+\u003c/sup\u003e) due to the strong covalent Ru-O bonds. Whereas resulting in higher activity, the accompanying soluble Ru (e.g., RuO\u003csub\u003e4\u003c/sub\u003e) derivatives leaching out, active sites rapid dissolution, crystal structure collapse, and catalytic performance deterioration over extended periods are hardly avoidable\u003csup\u003e13,14,15,16,17\u003c/sup\u003e. Thus, it is urgent yet challenging to discover a strategy that can effectively circumvent the occurrence of LOM while also optimizing the absorption behavior of multiple AEM key species on RuO\u003csub\u003e2\u003c/sub\u003e electrocatalysts. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIt has been proved that the metal oxide (MOx) is endowed by the weakened M-O covalency bonding when meticulously stretching the lattice distance\u003csup\u003e18,19,20,21,22\u003c/sup\u003e. That is the introduction of lattice tensile strain (TS) effectively bypasses the LOM and related negative effects on the crystal integrity, resulting in the improved anti-corrosion ability of RuO\u003csub\u003e2\u003c/sub\u003e acidic OER catalysts. Modifying this new tensile strained RuO\u003csub\u003e2\u003c/sub\u003e (TS-RuO\u003csub\u003e2\u003c/sub\u003e) with extrinsic metal atoms then evokes the alterations in its intrinsic unfavorable electronic configurations, wherein the careful metal selection could finally achieve the optimization absorption of the intermediates on Ru active sites during the AEM process (Scheme 1a)\u003csup\u003e23,24,25,26,27,28,29\u003c/sup\u003e. Those modulations are highly desired to break the activity-stability trade-off of RuO\u003csub\u003e2\u003c/sub\u003e for acidic water electrooxidation, and no contribution has been proved experimentally or theoretically (Scheme 1b). \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eHerein, the quenching process assisted by the molten salt bath was devised to decorate the homemade ruthenium dioxide (RuO\u003csub\u003e2-x\u003c/sub\u003e) with the relatively apparent and uniform TS (TS-RuO\u003csub\u003e2-x\u003c/sub\u003e), meanwhile maintaining the higher integrity of small nano-sized crystals. Then, homogenously incorporating the trace amounts of strontium (Sr, 4d\u003csup\u003e7\u003c/sup\u003e5s\u003csup\u003e1\u003c/sup\u003e) and tantalum (Ta, 4f\u003csup\u003e14\u003c/sup\u003e5d\u003csup\u003e3\u003c/sup\u003e6s\u003csup\u003e2\u003c/sup\u003e) atoms (named TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e) to substitute the Ru (4d\u003csup\u003e7\u003c/sup\u003e5s\u003csup\u003e1\u003c/sup\u003e) position triggers the optimized electrons redistribution among active sites. Such improved catalytic kinetics were not only reflected by the rather lower overpotential (166 mV at 10 mA cm\u003csup\u003e-2\u003c/sup\u003e) but also the continuous operations on TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e during 1000 h with a degradation rate of 0.02\u0026nbsp;mV/h in 0.5 H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e solution, as well as an order of magnitude higher stability number (S-number, mol\u003csub\u003eO2\u003c/sub\u003e/mol\u003csub\u003eRu-dissolved\u003c/sub\u003e) than catalyst without TS (Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e). Comprehensive investigations convinced that TS-induced lower Ru-O covalency contributes to enhancing stability by avoiding the LOM pathways. The electronic modulations originating from dual atom substitution play a primary role in accelerating the OER kinetics. In addition, a two-electrodes device assembled by TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e catalyst exhibits ultrastable acidic water electrolysis of 500 and 100 h at current densities of 10 and 50 mA cm\u003csup\u003e-2\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e"},{"header":"Results and Discussion","content":"\u003cdiv id=\"Sec2\" class=\"Section2\"\u003e\n \u003ch2\u003eSynthesis and characterization of the nanocatalysts\u003c/h2\u003e\n \u003cp\u003eTS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e nanocatalysts were formed in the molten salts (NaCl\u0026thinsp;+\u0026thinsp;NaNO\u003csub\u003e3\u003c/sub\u003e) at 400 ℃ after preparing the precursor with 1/10 Sr, 1/10 Ta, and 8/10 molar ratio column feed. Due to the repulsion between cationic Na and Ru spreading the nucleation and crystallographic points, such a hot liquid bath allowed the uniform distribution of small-sized nanoparticles with higher crystal phases while eliminating the dopants-induced mutation of RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e morphology\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. Thereafter, the liquid mixture was immediately quenched in excessive water (about 20 ℃), and crystallographic growth was abruptly stopped. Alkali metal salts therein were instantly and completely dissolved in cool water, which well-preserved the expanded lattice parameters and relaxed Ru-O interaction of high-temperature status, finally the TS was generated in RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e catalysts\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e31\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e32\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e. With the sole incorporation of Sr and Ta during a similar process, TS-Sr\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.9\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e and TS-Ta\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.9\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e were obtained respectively (Fig.\u003cspan class=\"InternalRef\"\u003eS1\u003c/span\u003e). In contrast, the RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e and Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e catalysts without TS were prepared via traditional natural cooling and followed a sonication-assisted water washing step. The intact nanoparticulate crystal with uniform 10\u0026ndash;20 nm size and dominant (110) facet orientation of all RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e catalysts is shown in Transmission electron microscopy (TEM) and High-resolution TEM (HRTEM) images (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ea, Figs.S2-S6a,b).\u003c/p\u003e\n \u003cp\u003eHigh-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and corresponding EDS elemental mapping images reflect the atomic homogenous distribution of Sr and Ta elements among bulk phase (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb, Figs. S2-S6c). As observed from the HRTEM images, the average lattice spacing along (110) for RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e is 0.314 nm (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ec), which is rather close to the 0.315 nm of the theoretical value for commercial RuO\u003csub\u003e2\u003c/sub\u003e (PDF 96-210-1931). The value is increased to 0.328 nm after TS modifications in TS-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e (Fig. S3d) and further 0.33 nm in TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ee). Meanwhile, the 0.333 nm and 0.328 nm are also displayed in the TS-Sr\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.9\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (Fig. S4d) and TS-Ta\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.9\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (Fig. S5d) nanocatalysts, respectively, in contrast to 0.318 nm of Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e case (Fig. S6d). Serving our RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e as the benchmark quantifies the axial TS about 4.5% (TS-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e), 5.1% (TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e), 5.1% (TS-Sr\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.9\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e), 4.5% (TS-Ta\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.9\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e), and 1.3% (Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e) along (110) facets (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eg). The spatial TS distribution components (\u003cem\u003e\u0026epsilon;\u003c/em\u003e\u003csub\u003exx\u003c/sub\u003e perpendicular to (110) and \u003cem\u003e\u0026epsilon;\u003c/em\u003e\u003csub\u003eyy\u003c/sub\u003e in the (110) plane associated with contraction/expansion of the respective lattice vectors and \u003cem\u003e\u0026epsilon;\u003c/em\u003e\u003csub\u003exy\u003c/sub\u003e shear strain) are mapped by the geometric-phase analysis (GPA)\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e. It displays that the values of \u003cem\u003e\u0026epsilon;\u003c/em\u003e\u003csub\u003exx\u003c/sub\u003e, \u003cem\u003e\u0026epsilon;\u003c/em\u003e\u003csub\u003exy\u003c/sub\u003e, and \u003cem\u003e\u0026epsilon;\u003c/em\u003e\u003csub\u003eyy\u003c/sub\u003e are nearly zero on the surface of RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ed), whereas those distinctly increase on tensile strained samples, especially the respective \u003cem\u003e\u0026epsilon;\u003c/em\u003e\u003csub\u003eyy\u003c/sub\u003e maximum values of ~\u0026thinsp;4.5% and ~\u0026thinsp;5% are reached on the TS-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e (Fig. S3e) and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ef), providing the visual evidence of the TS presence in the (110) plane. Lattice expansion also can be indicated by the (110) diffraction peak downshifting compared to those of RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e and Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e in the X-ray diffraction (XRD) pattern (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eh, S7).\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eElectronic structure characterizations\u003c/h3\u003e\n\u003cp\u003eTo explore the effects of TS and Sr-Ta dual dopants on the electronic structures and chemical states, X-ray photoelectron spectroscopy (XPS) was first carried out and carefully investigated. As shown in Fig.\u0026nbsp;2a, the M-O\u003csub\u003eL\u003c/sub\u003e (lattice oxygen) peak in O1s XPS slightly upshifts after TS modifications, but the extrinsic Sr-Ta atoms co-insertion brings significant alterations to the oxygen chemical state in terms of a rather noticeable shifting of the M-O\u003csub\u003eL\u003c/sub\u003e peak. For TS-Sr\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.9\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e and TS-Ta\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.9\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e catalysts (Fig. S8a), the sole Sr and Ta atoms substitution gives rise to an opposite change of M-O\u003csub\u003eL\u003c/sub\u003e peak position due to the large difference between the valent electrons configurations of Sr\u003csup\u003e2+\u003c/sup\u003e and Ta\u003csup\u003e5+\u003c/sup\u003e. Thus, the presence of codoped Sr-Ta may optimize the electronic structure of O sites to some extent, which is favorable for the deprotonation process of *OH intermediate during the OER\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e34\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e35\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e. A similar conclusion also can be obtained from the Ru 3d XPS spectra, in which the electronic and valent modulations of Ru sites primarily are ascribed from the simultaneous Sr and Ta doping rather than the TS presence (Figs.\u0026nbsp;2b, S8). Convinced that the foreign atoms primarily result in moderate alterations in chemical state and electronic density on Ru sites, ensuring the optimal oxophilicity towards the species during OER\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e36\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. The ratios of (oxygen vacancy) V\u003csub\u003eO\u003c/sub\u003e/ M-O\u003csub\u003eL\u003c/sub\u003e and Ru\u003csup\u003e\u0026gt;\u0026thinsp;4+\u003c/sup\u003e/Ru\u003csup\u003e4+\u003c/sup\u003e are summarized in Figs. 2c and 3d, respectively, indicating that the TS gradually alleviates the formation rate of V\u003csub\u003eO\u003c/sub\u003e and unstable Ru composition, which solids the integrity of crystal RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e. While the independently cationic Sr\u003csup\u003e2+\u003c/sup\u003e and Ta\u003csup\u003e5+\u003c/sup\u003e affect those components\u0026apos; ratios dramatically, especially showing the opposite tendency in Sr\u003csup\u003e2+\u003c/sup\u003e and Ta\u003csup\u003e5+\u003c/sup\u003e cases. The balance between (V\u003csub\u003eO\u003c/sub\u003e)/ M-O\u003csub\u003eL\u003c/sub\u003e and Ru\u003csup\u003e\u0026gt;\u0026thinsp;4+\u003c/sup\u003e/Ru\u003csup\u003e4+\u003c/sup\u003e occurs as a result of the synergistic interaction between Ru and codoped Sr\u003csub\u003e/\u003c/sub\u003eTa atoms, rendering the preferable catalytic ability on both intrinsic O and Ru sites in TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e\u003csup\u003e38,39\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eIn addition, the change of Ru valence states and Ru-O bond lengths are revealed by the Ru K-edge X-ray absorption near-edge spectroscopy (XANES) (Figs.\u0026nbsp;2e, S9a). The absorption edge of our RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e shifts to a higher energy position compared with those of references, including RuO\u003csub\u003e2\u003c/sub\u003e (r-RuO\u003csub\u003e2\u003c/sub\u003e), RuCl\u003csub\u003e3\u003c/sub\u003e (r-RuCl\u003csub\u003e3\u003c/sub\u003e), and Ru metal (r-Ru), indicating that the average oxidation state of Ru in RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e is higher than 4+, which is also consistent with the XPS conclusion about the abundant V\u003csub\u003eO\u003c/sub\u003e and Ru\u003csup\u003e\u0026gt;\u0026thinsp;4+\u003c/sup\u003e presence. Introducing the lattice TS decreases the valence state reflected by the absorption edge negative shifting of TS-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e. Like the analysis from the XPS, the moderate valence state of Ru can be achieved once co-modulated by the Sr and Ta atoms, while its Ru-K absorption edge is positioned between that of sole Sr and Ta cases (Figs. S9b,c).\u003c/p\u003e\n\u003cp\u003eThose suggest that more favorable electronic redistributions among active sites are facilely triggered by synergetic modulations of atomic Sr\u003csup\u003e2+\u003c/sup\u003e and Ta\u003csup\u003e5+\u003c/sup\u003e (details in supporting information). The extended X-ray absorption fine structure (EXAFS) spectra show a slight stretch of Ru-O bond in all TS samples (Figs. 2f, S9d). Interestingly, a strained effect also stretches the Ru-Ru and Ru-O-M lengths longer compared with those of RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e due to TS-induced variation of spatial lattice parameters, possibly corresponding to the strain existence along \u003cem\u003e\u0026epsilon;\u003c/em\u003e\u003csub\u003exx\u003c/sub\u003e, and \u003cem\u003e\u0026epsilon;\u003c/em\u003e\u003csub\u003eyy\u003c/sub\u003e directions. Thus, it is predictable that the elongated Ru-O bonding and synergistic electronic interactions among Sr-Ru-Ta units can improve the stability-activity of RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e for acidic OER, respectively (Fig S10).\u003c/p\u003e\n\u003ch3\u003eElectrocatalytic activity and stability in acidic electrolyte\u003c/h3\u003e\n\u003cp\u003eTo unravel how the dominant contribution of TS and electronic modulations works in balancing the stability-activity trade-off, the electrocatalytic OER activity was measured with a three-electrode system in 0.5 M H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e, wherein our RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e catalysts, Pt wire, and Hg/Hg\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e were working, counter, and reference electrode respectively (Fig. S10). The linear sweep voltammetry (LSV) curves of all prepared nanocatalysts are shown in Figs. 3a,b. It can be noticed that TS and co-doped simultaneously improve the OER activity to various degrees. The overpotentials at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e achieved on RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e and TS-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e are about 243 mV and 210 mV, close to the most reported values (Supplementary Table \u003cspan class=\"InternalRef\"\u003eS1\u003c/span\u003e). Whereas only 183 mV and 166 mV overpotentials are required on Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e electrodes, respectively, outperforming the many latest excellent catalysts. Meanwhile, the Tafel slope values are significantly reduced from 154.5 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e of RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e to 67.9 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e of Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e and 56.6 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e of TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (Fig. 3c, Figs. S12a,b). Electronic modulation promotion is maximized under the co-presence of Sr and Ta. No distinct changes are observed from LSV curves obtained on the TS-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e, TS-Sr\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.9\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e, and TS-Ta\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.9\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e electrodes. Moreover, the intrinsic activity of Ru sites was examined by the electrochemically active surface area (ECSA) normalized\u003c/p\u003e\n\u003cp\u003eLSV curves (Fig. S13)\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e40\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e. Figure\u0026nbsp;3d presents the approximately close ECSA-current densities on Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e with the increase of potentials, and inconspicuous disparity can be noticed between RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e and TS-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e. And the emergence of the Sr-Ru-Ta unit enables the optimized intrinsic activity of Ru sites, resulting in the superior ECSA-normalized LSV curves to those of TS-Sr\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.9\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e, and TS-Ta\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.9\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (Fig. 3e). Similar phenomena are also reflected by the Ru mass-normalized LSV curves (Figs. S12c,d). These clues demonstrate the fact that the synergy of Sr and Ta electronic modulators primarily contributes to the enhanced activity of Ru sites than TS modification.\u003c/p\u003e\n\u003cp\u003eKeeping strong stability in acidic conditions while achieving outstanding OER activity always remains a great challenge for RuO\u003csub\u003e2\u003c/sub\u003e catalysts. Thus the chronopotentiometry curves (V-T) were first obtained at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e (Fig. 3f). Noticed that without lattice expansion, RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e and Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e electrodes display acceptable resistance to corrosion within the front 300 h, respectively possessing the decay rate of 0.25 mV/h and 0.39 mV/h. Impressively, a dozen times smaller decay rates are present on the TS-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e (0.03 mV/h) and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (0.02 mV/h) even during the continuous operation up to 1000 h. These illustrate that due to the decreased Ru-O covalency, the TS majorly functions on efficiently strengthening the RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e nanocrystal integrity and avoiding the LOM pathway\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e19\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e42\u003c/span\u003e\u003c/sup\u003e. The stability superiority of TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e also can be evidenced by the more harsh electrocatalysis (200 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e within 200 h) (Fig. 3g) and careful comparisons of overpotential at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e-measured stability period with abundant references catalysts (Fig. 3h, Supplementary Table \u003cspan class=\"InternalRef\"\u003eS1\u003c/span\u003e). The homemade water electrolyzer was assembled by TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (cathode) and commercial Pt/C (anode), delivering the 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e and 50 mAcm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e only at 1.45 V and 1.53 V in 0.5 M H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e, respectively, much lower than 1.55 V and 1.78 V of commercial RuO\u003csub\u003e2\u003c/sub\u003e (c-RuO\u003csub\u003e2\u003c/sub\u003e) and Pt/C benchmark (Fig.\u0026nbsp;3i). Thanks to the merits of TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e, our water electrolyzer can sustainably work over 500 h and 100 h at 10 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e and 50 mAcm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e without apparent degradation, presenting the promising potential for large-power applications (Figs. 3j and k).\u003c/p\u003e\n\u003ch3\u003eOrigin of improved stability\u003c/h3\u003e\n\u003cp\u003eUnderstanding which reaction pathway dominates is the premise before clarifying the origin of enhanced performance. Since the non-concerted proton-electron transfer step causes the typical pH-dependent OER behavior for the LOM mechanism, pH-dependent activity was measured on all catalysts (Fig. S14)\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e. As shown in Figs.\u0026nbsp;4a and b, pH-dependent phenomena of RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e are reversed after TS introduction due to the slopes of pH-overpotentials (5, 10, 20 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e) tending to be parallel, and the same feature also can be found in other strained catalysts (Fig. S14). This confirms that the lattice oxygen release was significantly alleviated to enable higher stability due to the TS presence. Isotopic oxygen (\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003eO) labeling experiments were further conducted in well-closed two-separated chamber cells to certify the suppressed LOM process induced by TS (Fig. S15)\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e42\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e. The gas products at the constant current density and period were collected to analyze in gas chromatography-mass spectrometry (GC-MS) (Fig.\u0026nbsp;4c, Figs. S16, S17). Noticed that the O\u003csub\u003e2\u003c/sub\u003e (\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003eO\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003eO) relative intensity on c-RuO\u003csub\u003e2\u003c/sub\u003e, RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e, and Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e surface achieve 3.9%, 2.9%, and 1.7%, while the TS-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e is reduced to 0.6% and 0.4%, respectively (Fig. 4d). These clues unambiguously corroborate the less participation of lattice oxygen on strained samples, enabling these prefer to the AEM mechanism. Thereafter, the in-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) was conducted to validate the exclusive AEM process (Fig. S18). As shown in Fig. 4e, an absorption band (~\u0026thinsp;1142 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) corresponding to the key water oxidation intermediate *OOH (AEM) can be observed and its intensity starts to gradually increase as the the potential is higher than 1.3 V\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e45\u003c/span\u003e\u003c/sup\u003e. An isotopic shift when the solvent is switched from H\u003csub\u003e2\u003c/sub\u003eO to D\u003csub\u003e2\u003c/sub\u003eO indicates that the vibrational mode of the species involves hydrogen\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e46\u003c/span\u003e\u003c/sup\u003e, excluding the direct O-O intramolecular coupling pathway and further verifying the AEM process (Fig.\u0026nbsp;4f)\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e47\u003c/span\u003e\u003c/sup\u003e. It is noteworthy that TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e displays rather higher vibration bands (*OOH and *OOD) intensity compared to those of RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e and TS-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e (Figs. 4g, S18b), indicating that the Sr and Ta incorporation greatly promotes the rate-determined reaction step of acidic OER.\u003c/p\u003e\n\u003cp\u003eDue to the AEM predominance, the Ru dissolution rate from TS-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e catalysts can be efficiently alleviated, as reflected by the ICP-OES measurements results (Figs. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003ea, S19a). Lattice expansion preserves the Ru atoms from corrosion, and dissolved Ru ions tend to a constant value after 50 min, in sharp contrast to the samples without TS. This promotion also can be demonstrated by that an order of magnitude higher S-number is achieved on TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (Figs. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003eb, S19b-S19e)\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e48\u003c/span\u003e\u003c/sup\u003e. Thus, acceptable alterations of chemical state and constituents emerge on the strained catalysts\u0026apos; surface even after 3000 CV cycles (Fig. S20, Supplementary Table S2). A rather higher portion of O\u003csub\u003eL\u003c/sub\u003e remains in O 1s XPS of post-TS-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e and post-TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e catalysts, whereas almost all O\u003csub\u003eL\u003c/sub\u003e depletion in cases of post-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e and post-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (Figs. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003ec, S20a). Likewise, in Ru 3d XPS spectra of post-reaction samples, a slight increase of Ru\u003csup\u003e\u0026gt;\u0026thinsp;4+\u003c/sup\u003e/Ru\u003csup\u003e4+\u003c/sup\u003e ratio is observed after the reaction due to the TS presence (Figs. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003ed, S20b), corresponding to the higher valence state observed in XANES. Those are in stark contrast to the 100% Ru\u003csup\u003e\u0026gt;\u0026thinsp;4+\u003c/sup\u003e species that remained on the surface of post-RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e and post-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e. In addition, the rigidity of lattice TS itself is also praiseworthy, reflected by the unchanged bonding of Ru-O and Ru-O-M in EXAFS (Fig. S21), as well as the stable d-spacing distance (110) and positive strain component values of GPA (Figs. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003ee, \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003ef, and Fig. S22).\u003c/p\u003e\n\u003ch3\u003eOrigin of enhanced activity\u003c/h3\u003e\n\u003cp\u003eOnce the AEM mechanism is confirmed, the OER activity is mainly controlled by the key species transfer behavior. In-situ electrochemical impedance spectroscopy (in-situ EIS) was measured from programmed 1.0 V to 1.5 V (vs. RHE) within the 10\u003csup\u003e2\u003c/sup\u003e-10\u003csup\u003e5\u003c/sup\u003e Hz frequency range in 0.5 M H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e (Figs. 6a, S23, and S24). Corresponding equivalent circuit models show three tandem components, wherein the Rs represent solution resistance, and the other two tandem components respectively reflect the charge-transfer kinetics in electrical double-layer (Q\u003csub\u003e1\u003c/sub\u003e/R\u003csub\u003e1\u003c/sub\u003e) and intermediates transfer among the active site (Q\u003csub\u003e2\u003c/sub\u003e/R\u003csub\u003e2\u003c/sub\u003e) (Fig.\u0026nbsp;6b)\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e49\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e50\u003c/span\u003e\u003c/sup\u003e. Then related species transfer numbers and related resistance were carefully simulated (Supplementary Tables S3-S9, Fig. S25). It is noteworthy that the lowest Q\u003csub\u003e1\u003c/sub\u003e values of RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e are increased after Sr and Ta co-presence and the R\u003csub\u003e1\u003c/sub\u003e on these two samples tends to approximate as the potential reaches about 1.35 V (close to OER onset potentials) (Fig. 6c). Meanwhile, the TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e is featured by the much higher Q\u003csub\u003e1\u003c/sub\u003e and lower R\u003csub\u003e1\u003c/sub\u003e, manifesting the enlarged active surface area and facilitated charge transfer mainly induced by the electronic modulators. Thus, the almost same Q\u003csub\u003e2\u003c/sub\u003e and relatively similar R\u003csub\u003e2\u003c/sub\u003e values are present on the co-doped catalyst surface (Fig. 6d). The Bode plot demonstrates that the 1.4 V onset potential of RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e (Fig. S23d) is reduced to 1.35 V of TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (Figs. 6e, S24h). Unlike the electrode evolution process undergone by c-RuO\u003csub\u003e2\u003c/sub\u003e (Fig. S23b), associated peaks are absent in high-frequency regions in our catalysts, providing veritable catalytic phases\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e51\u003c/span\u003e\u003c/sup\u003e. Also noticed that only a negligible difference in phase angle peaks at 1.5 V is found after TS modification, whereas Sr and Ta introduction results in the rather lower phase angle peaks, especially the 10.051 \u0026theta; and 9.557 \u0026theta; observed on Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (Fig. 6e). Those indicate that TS weakly contributes to the facilitated migration kinetics of active species on Ru and O sites, but the Sr-Ru-Ta unit significantly does.\u003c/p\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003eTheoretical investigation\u003c/h2\u003e\n \u003cp\u003eAfter building the configurations including RuO\u003csub\u003e2\u003c/sub\u003e, TS-RuO\u003csub\u003e2\u003c/sub\u003e (5% TS), Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e, and TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e (5% TS) to represent corresponding experiments models (Figs. S26a-d), density functional theory (DFT) calculations were carefully conducted. It reveals that the energy barrier of Vo formation and OER pathway can be primarily tuned fluctuation of \u0026epsilon;\u003csub\u003ep\u003c/sub\u003e and \u0026epsilon;\u003csub\u003ed\u003c/sub\u003e (d band center). This synergy prefers to optimize the absorption ability of active sites since too weak or too strong affinity for oxygen and proton intermediates can be avoided. Like conclusions from experiments, the electronic structural alterations are induced by the co-doping effect more efficiently\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Then both AEM and LOM free energy of OER coordinates was calculated (Figs. S27-S35). The theoretical overpotentials (\u0026eta;) at U\u0026thinsp;=\u0026thinsp;1.23 V of LOM and AEM on RuO\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e surface are respective 1.95 eV and 0.8 eV (Fig. 6g). As high as \u0026eta;\u0026thinsp;=\u0026thinsp;2.19 eV is required for the LOM pathway on the TS-modified model, certifying that the TS mainly constrains the LOM participation during OER (Fig. S27a). Extrinsic Sr and Ta modulators accelerate AEM and LOM kinetics simultaneously due to the respectively smaller \u0026eta;\u0026thinsp;=\u0026thinsp;1.61 eV and \u0026eta;\u0026thinsp;=\u0026thinsp;0.56 eV, which may result in the instability of Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e (Fig. S27b), whereas LOM of \u0026eta;\u0026thinsp;=\u0026thinsp;2.08 eV and AEM of \u0026eta;\u0026thinsp;=\u0026thinsp;0.52 eV are concurrent (Fig. 6h). It is noteworthy that only suitable movement of \u0026epsilon;\u003csub\u003ep\u003c/sub\u003e and \u0026epsilon;\u003csub\u003ed\u003c/sub\u003e finally minimizes the AEM energy barrier through making the simultaneous improvement of deprotonation on O and key intermediates sorption on Ru sites (Fig. 6i)\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e52\u003c/span\u003e\u003c/sup\u003e. These results jointly support the fact that a balanced stability-activity trade-off is experimentally achieved on our TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn summary, tensile strained Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e nanocatalysts were prepared through the molten salt assistant quench process. The TS along the nanocrystalline phases (110) stretches the Ru-O bond lengths and weakens the covalency, thereby avoiding the LOM pathway by making V\u003csub\u003eO\u003c/sub\u003e formation more difficult and enhancing long-term durability. Furthermore, the synergic functionality of Sr and Ta dopants has been proven to optimize the electronic configuration, favoring the adsorption-desorption of intermediates on Ru/O sites and lowering the energy barriers for OER. Thus, our TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2\u0026minus;x\u003c/sub\u003e electrode demonstrates outstanding stability while outperforming most reported acidic OER activities, as evidenced by comprehensive experimental and theoretical characterizations. This work not only unravels the respective contribution of TS and doping effect but also showcases an elaborate design of outstanding catalysts with strengthened stability toward OER.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData availability \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that all data supporting the findings of this study are available from the corresponding author upon request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the National Research Foundation of Korea (NRF) grant (NRF-2022R1A2C2093415) and the Qilu Young Scholars Program of Shandong University (China). The authors thank the BL10C beamline of the Pohang Light Source (PLS-II, Korea) Facility for providing synchrotron beam time.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eY. L. designed all experimental schemes, conceptualization, and writing drafts. Y. L. and Y. W. carried out the experiments together.\u003csup\u003e\u0026nbsp;\u003c/sup\u003eH. L. achieved the DFT calculations.\u0026nbsp;M. G. K. conducted the XAS experiments and analysis. M. W. and H. L. gave the direction, supervision, and editing of this draft.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing financial interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAdditional Information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSupporting information\u0026nbsp;\u003c/strong\u003eThe online version contains supplementary information available at\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eChu S, Majumdar A (2012) Opportunities and challenges for a sustainable energy future. Nature 488:294\u0026ndash;303\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi A et al (2024) Atomically dispersed hexavalent iridium oxide from MnO\u003csub\u003e2\u003c/sub\u003e reduction for oxygen evolution catalysis. Science 384:666\u0026ndash;670\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang Z, Zheng Y-R, Chorkendorff I, N\u0026oslash;rskov JK (2020) Acid-Stable Oxides for Oxygen Electrocatalysis. ACS Energy Lett 5:2905\u0026ndash;2908\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAn L et al (2021) Recent Development of Oxygen Evolution Electrocatalysts in Acidic Environment. Adv Mater 33:e2006328\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGrimaud A et al (2016) Activation of surface oxygen sites on an iridium-based model catalyst for the oxygen evolution reaction. Nat Energy 2\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eElmaalouf M et al (2021) The origin of the high electrochemical activity of pseudo-amorphous iridium oxides. Nat Commun 12:3935\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFan Z et al (2021) Extraordinary acidic oxygen evolution on new phase 3R-iridium oxide. Joule 5:3221\u0026ndash;3234\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLyons ME, Floquet S (2011) Mechanism of oxygen reactions at porous oxide electrodes. Part 2\u0026ndash;Oxygen evolution at RuO\u003csub\u003e2\u003c/sub\u003e, IrO\u003csub\u003e2,\u003c/sub\u003e and Ir\u003csub\u003ex\u003c/sub\u003eRu\u003csub\u003e1-x\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e electrodes in aqueous acid and alkaline solution. Phys Chem Chem Phys 13:5314\u0026ndash;5335\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eScott SB et al (2022) The low overpotential regime of acidic water oxidation part II: trends in metal and oxygen stability numbers. Energy Environ Sci 15:1988\u0026ndash;2001\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGao J, Tao H, Liu B (2021) Progress of Nonprecious-Metal-Based Electrocatalysts for Oxygen Evolution in Acidic Media. Adv Mater 33:e2003786\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi S et al (2024) Exploring the potential Ru-based catalysts for commercial-scale polymer electrolyte membrane water electrolysis: A systematic review. Prog Mater Sci 145:101294\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSong J et al (2020) A review on fundamentals for designing oxygen evolution electrocatalysts. Chem Soc Rev 49:2196\u0026ndash;2214\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGrimaud A et al (2017) Activating lattice oxygen redox reactions in metal oxides to catalyse oxygen evolution. Nat Chem 9:457\u0026ndash;465\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJin H et al (2023) Dynamic rhenium dopant boosts ruthenium oxide for durable oxygen evolution. Nat Commun 14:354\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKuznetsov DA, Naeem MA, Kumar PV, Abdala PM, Fedorov A, Muller CR (2020) Tailoring Lattice Oxygen Binding in Ruthenium Pyrochlores to Enhance Oxygen Evolution Activity. J Am Chem Soc 142:7883\u0026ndash;7888\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePan Y et al (2020) Direct evidence of boosted oxygen evolution over perovskite by enhanced lattice oxygen participation. Nat Commun 11:2002\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang Q et al (2023) Long-Term Stability Challenges and Opportunities in Acidic Oxygen Evolution Electrocatalysis. Angew Chem Int Ed Engl 62:e202216645\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi L et al (2024) Lanthanide-regulating Ru-O covalency optimizes acidic oxygen evolution electrocatalysis. Nat Commun 15:4974\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePing X et al (2024) Locking the lattice oxygen in RuO\u003csub\u003e2\u003c/sub\u003e to stabilize highly active Ru sites in acidic water oxidation. Nat Commun 15:2501\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQin Y et al (2022) RuO\u003csub\u003e2\u003c/sub\u003e electronic structure and lattice strain dual engineering for enhanced acidic oxygen evolution reaction performance. Nat Commun 13:3784\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYagi S et al (2015) Covalency-reinforced oxygen evolution reaction catalyst. Nat Commun 6:8249\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHao S et al (2021) Torsion-strained iridium oxide for efficient acidic water oxidation in proton exchange membrane electrolyzers. Nat Nanotechnol 16:1371\u0026ndash;1377\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHao S et al (2020) Dopants fixation of Ruthenium for boosting acidic oxygen evolution stability and activity. Nat Commun 11:5368\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHe J, Li W, Xu P, Sun J (2021) Tuning electron correlations of RuO\u003csub\u003e2\u003c/sub\u003e by co-doping of Mo and Ce for boosting electrocatalytic water oxidation in acidic media. Appl Catal B 298:120528\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJoo J et al (2022) Mn-Dopant Differentiating the Ru and Ir Oxidation States in Catalytic Oxides Toward Durable Oxygen Evolution Reaction in Acidic Electrolyte. Small Methods 6:e2101236\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSun W, Song Y, Gong XQ, Cao LM, Yang J (2015) An efficiently tuned d-orbital occupation of IrO\u003csub\u003e2\u003c/sub\u003e by doping with Cu for enhancing the oxygen evolution reaction activity. Chem Sci 6:4993\u0026ndash;4999\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang J et al (2022) Single-site Pt-doped RuO\u003csub\u003e2\u003c/sub\u003e hollow nanospheres with interstitial C for high-performance acidic overall water splitting. Sci Adv 8:eabl9271\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu ZY et al (2023) Non-iridium-based electrocatalyst for durable acidic oxygen evolution reaction in proton exchange membrane water electrolysis. Nat Mater 22:100\u0026ndash;108\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang D et al (2023) Construction of Zn-doped RuO\u003csub\u003e2\u003c/sub\u003e nanowires for efficient and stable water oxidation in acidic media. Nat Commun 14:2517\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGupta SK, Mao Y (2021) A review on molten salt synthesis of metal oxide nanomaterials: Status, opportunity, and challenge. Prog Mater Sci 117:100734\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu T, Yang S, Guan J, Niu J, Zhang Z, Wang F (2022) Quenching as a Route to Defect-Rich Ru-Pyrochlore Electrocatalysts toward the Oxygen Evolution Reaction. Small Methods 6:e2101156\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYe C et al (2021) Activating Metal Oxides Nanocatalysts for Electrocatalytic Water Oxidation by Quenching-Induced Near-Surface Metal Atom Functionality. J Am Chem Soc 143:14169\u0026ndash;14177\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKumar A et al (2021) Discovering ultrahigh loading of single-metal-atoms via surface tensile-strain for unprecedented urea electrolysis. Energy Environ Sci 14:6494\u0026ndash;6505\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDeng L et al (2023) Valence Oscillation of Ru Active Sites for Efficient and Robust Acidic Water Oxidation. Adv Mater 35:e2305939\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang K et al (2022) Ru/Se-RuO\u003csub\u003e2\u003c/sub\u003e Composites via Controlled Selenization Strategy for Enhanced Acidic Oxygen Evolution. Adv Funct Mater 33\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee K et al (2023) Modulating the valence electronic structure using earth-abundant aluminum for high-performance acidic oxygen evolution reaction. Chem 9:3600\u0026ndash;3612\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHan N et al (2024) Lowering the kinetic barrier via enhancing electrophilicity of surface oxygen to boost acidic oxygen evolution reaction. Matter 7:1330\u0026ndash;1343\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWen Y et al (2022) Introducing Bronsted acid sites to accelerate the bridging-oxygen-assisted deprotonation in acidic water oxidation. Nat Commun 13:4871\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu Q et al (2024) Boosting electrocatalytic performance via electronic structure regulation for acidic oxygen evolution. iScience 27:108738\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu Y et al (2024) Insight into Controllable Metal-Support Interactions in Metal/Metal Electrocatalysts for Efficient Energy-Saving Hydrogen Production. ACS Nano 18:874\u0026ndash;884\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHao J et al (2022) Unraveling the electronegativity-dominated intermediate adsorption on high-entropy alloy electrocatalysts. Nat Commun 13:2662\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWen Y et al (2021) Stabilizing Highly Active Ru Sites by Suppressing Lattice Oxygen Participation in Acidic Water Oxidation. J Am Chem Soc 143:6482\u0026ndash;6490\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGiordano L et al (2016) pH dependence of OER activity of oxides: Current and future perspectives. Catal Today 262:2\u0026ndash;10\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang N et al (2020) Lattice oxygen activation enabled by high-valence metal sites for enhanced water oxidation. Nat Commun 11:4066\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSu H et al (2021) In-situ spectroscopic observation of dynamic-coupling oxygen on atomically dispersed iridium electrocatalyst for acidic water oxidation. Nat Commun 12:6118\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePark K, Kim Y, Lee KJ (2019) Analysis of deuterated water contents using FTIR bending motion. J Radioanal Nucl Chem 322:487\u0026ndash;493\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhu W et al (2023) Direct Dioxygen Radical Coupling Driven by Octahedral Ruthenium-Oxygen-Cobalt Collaborative Coordination for Acidic Oxygen Evolution Reaction. J Am Chem Soc 145:17995\u0026ndash;18006\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGeiger S et al (2018) The stability number as a metric for electrocatalyst stability benchmarking. Nat Catal 1:508\u0026ndash;515\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu Y et al (2022) Unveiling the Protonation Kinetics-Dependent Selectivity in Nitrogen Electroreduction: Achieving 75.05% Selectivity. Angew Chem Int Ed Engl 61:e202209555\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLu Y et al (2022) Tailoring Competitive Adsorption Sites by Oxygen-Vacancy on Cobalt Oxides to Enhance the Electrooxidation of Biomass. Adv Mater 34:e2107185\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGu K et al (2021) Defect-Rich High-Entropy Oxide Nanosheets for Efficient 5-Hydroxymethylfurfural Electrooxidation. Angew Chem Int Ed Engl 60:20253\u0026ndash;20258\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShi Z et al (2023) Customized reaction route for ruthenium oxide towards stabilized water oxidation in high-performance PEM electrolyzers. Nat Commun 14:843\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Schemes","content":"\u003cp\u003eScheme 1 is available in the Supplementary Files section\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"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-4721957/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4721957/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eRuthenium dioxide (RuO₂) electrocatalysts for acidic oxygen evolution reaction (OER) suffer from mediocre activity and rather instability induced by high Ru-O covalency. Here, the tensile strained Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e (TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e) nanocatalysts were synthesized via a molten salt-assisted quenching strategy. The TS spacially elongates the Ru-O bond and reduces covalency, thereby inhibiting the lattice oxygen participation and structural decomposition. The synergistic electronic modulations among Sr-Ru-Ta groups both optimize deprotonation on oxygen sites and intermediates absorption on Ru sites, lowering the OER energy barrier. Those result in a well-balanced activity-stability profile, confirmed by comprehensive experimental and theoretical analyses. Our TS-Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e electrode demonstrated an overpotential of 166 mV at 10 mA cm\u003csup\u003e-2 \u003c/sup\u003ein 0.5 M H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e and an order of magnitude higher S-number, indicating exceptional stability compared to bare Sr\u003csub\u003e0.1\u003c/sub\u003eTa\u003csub\u003e0.1\u003c/sub\u003eRu\u003csub\u003e0.8\u003c/sub\u003eO\u003csub\u003e2-x\u003c/sub\u003e. It exhibited degradation rates of 0.02 mV/h at 10 mA cm\u003csup\u003e-2 \u003c/sup\u003eover 1000 h and 0.25 mV/h at 200 mA cm\u003csup\u003e-2 \u003c/sup\u003eover 200 h. This study elucidates the effectiveness of tensile strain and strategic doping in enhancing the activity and stability of Ru-based catalysts for acidic OER.\u003c/p\u003e","manuscriptTitle":"Effectiveness of strain and dopants on breaking the activity-stability trade-off of RuO2 acidic oxygen evolution electrocatalysts","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-01 04:49:43","doi":"10.21203/rs.3.rs-4721957/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":"a2e1f261-d48e-4b8d-bafa-41bbc5a37cb1","owner":[],"postedDate":"August 1st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":35424703,"name":"Physical sciences/Chemistry/Electrochemistry/Electrocatalysis"},{"id":35424704,"name":"Physical sciences/Materials science/Nanoscale materials/Synthesis and processing"},{"id":35424705,"name":"Physical sciences/Nanoscience and technology/Nanoscale materials/Structural properties"},{"id":35424706,"name":"Physical sciences/Chemistry/Energy"},{"id":35424707,"name":"Physical sciences/Materials science/Materials for energy and catalysis/Electrocatalysis"}],"tags":[],"updatedAt":"2025-02-18T08:07:11+00:00","versionOfRecord":{"articleIdentity":"rs-4721957","link":"https://doi.org/10.1038/s41467-025-56638-8","journal":{"identity":"nature-communications","isVorOnly":false,"title":"Nature Communications"},"publishedOn":"2025-02-17 05:00:00","publishedOnDateReadable":"February 17th, 2025"},"versionCreatedAt":"2024-08-01 04:49:43","video":"","vorDoi":"10.1038/s41467-025-56638-8","vorDoiUrl":"https://doi.org/10.1038/s41467-025-56638-8","workflowStages":[]},"version":"v1","identity":"rs-4721957","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4721957","identity":"rs-4721957","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}