Iron and oxygen vacancies co-modulated adsorption evolution and lattice oxygen dual-path mechanism for enhanced ampere-level freshwater/seawater oxidation

Iron and oxygen vacancies co-modulated adsorption evolution and lattice oxygen dual-path mechanism for enhanced ampere-level freshwater/seawater oxidation | 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 Iron and oxygen vacancies co-modulated adsorption evolution and lattice oxygen dual-path mechanism for enhanced ampere-level freshwater/seawater oxidation Faming Gao, xiwen tao, Li Hou, xinyi wang, jing jin, huana li This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6367775/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 02 Oct, 2025 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract Conjointly activating metal and lattice oxygen sites to trigger the adsorbate evolution and lattice oxygen mechanisms coupled path holds promise for balancing activity and stability in oxygen evolution reaction (OER) catalysts, yet confronting significant challenges. Herein, we develop Fe species and oxygen vacancies co-regulated Ni-(oxy)hydroxide (O V -Ni(Fe)OOH), derived from deep reconstruction of Fe-Ni 2 P/NiMoO 4 pre-catalyst during OER, which realizes the AEM-LOM dual-path mechanism with optimal metal-oxygen covalent bonds, as confirmed via in-situ mass/spectroscopy spectrometry and chemical probes. Experimental details and theoretical calculation analysis reveals the enhanced AEM kinetics on the Ni site via the co-regulation of Fe species and O V , featuring upshifted Ni 3 d band centers, while the Fe incorporation activates the O site with preferable adsorption free energy for LOM intermediates. Benefiting from the AEM-LOM dual-path mechanism, the activated Fe-Ni 2 P/NiMoO 4 catalyst affords an ampere-scale current density of 1.0 A cm − 2 at low overpotentials of 275 and 299 mV in 1 M KOH and 1 M KOH + seawater, respectively, and maintains seawater electrocatalysis for 480 h in the anion exchange membrane water electrolysis (AEMWE) cell. This work demonstrates a strategy to trigger the dual-path OER mechanism for efficient and stable electrocatalytic water splitting under harsh conditions. Physical sciences/Chemistry/Catalysis/Electrocatalysis Physical sciences/Materials science/Nanoscale materials/Electronic properties and materials nickel molybdate hydrate reconstruction dual-path mechanism oxygen evolution reaction seawater electrolysis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Alkaline water electrolysis as an efficient, clean, and environmentally benign technology of hydrogen production, has immense development promises 1 . However, the anodic oxygen evolution reaction (OER) goes through slow reaction dynamics because of the complicated four-electron transfer procedure, severely impeding the overall water splitting (OWS) efficiency 2 , 3 . Particularly in the harsh and complex seawater environments, the presence of insoluble impurities and the chloride evolution reaction (ClER) pose significant challenges to the OER kinetics and long-term durability of anode 4 . Therefore, designing the high-activity and robust OER catalysts is imperative to achieve the industry-scale freshwater/seawater oxidation. Reported researches have confirmed that the intrinsic OER performance of electrocatalysts possesses strong relevance to the reaction pathway of active sites 5 . Generally, the main pathways for alkaline OER are classified into two types: adsorbate evolution and lattice oxygen mechanisms (AEM and LOM) 6 . For the AEM, the binding strength between the metal sites and oxygenated intermediates (*O, *OH, and *OOH) plays a significant role of catalytic activity, wherein the inherent linear-scaling relationship (ΔG OOH = ΔG OH + 3.2 ± 0.2 eV) of the binding energies between *OH and *OOH limit the minimal overpotential of 370 mV vs. RHE to accelerate water oxidation 7 – 10 . In sharp contrast, the LOM achieves efficient O 2 release via the direct coupling of *O and oxygen ligand, circumventing the high barrier step of *OOH formation, thus requiring a lower theoretic overpotential 9 . Nevertheless, the dominant LOM pathway involves repeated refilling/release of lattice oxygen, leading to the unstable structure, and consequently abating the activity and durability of catalysts 11 . Undoubtedly, compared with the single OER pathway, dual-path catalysts following the AEM-LOM coupled mechanism can obviate the scaling relationship to achieve high OER activity without diminishing the stability 12 , 13 . However, developing the dual-path catalysts faces various challenges, as achieving the simultaneous electron transfer process on both metal sites and lattice oxygen within a single component or coordination environment depends on the optimal covalency of metal-oxygen (M-O) bonds 5 . Nanorod-like nickel molybdate hydrate (NiMoO 4 ·xH 2 O), a prospective pre-catalyst, undergoes a complete reconstruction accompanied by co-leaching of crystal water and MoO 4 2− ions under the alkaline OER conditions, resulting in the transformation to γ-NiOOH with the nanocrystal-amorphous feature 14 , 15 . And the NiMoO 4 ·xH 2 O derived γ-NiOOH is considered as an ideal substitute for RuO 2 and IrO 2 benchmarked catalysts due to the satisfactory OER performance 16 . Many outstanding works have so far confirmed that the reasonable modify strategies, such as introducing the exogenous heteroatoms or heterostructures 17 – 19 . can activate the lattice oxygen of NiMoO 4 ·xH 2 O catalyst systems for translating the mechanism from AEM to LOM, resulting in the derived NiOOH with preferable OER activity. On the other hand, introducing additional defects is a promising strategy to accelerate the reconfiguration of NiMoO 4 ·xH 2 O and reduce the covalency of Ni-O bonds, which can effectively optimize the AEM mechanism of the active phase 20 , 21 . Thus, constructing the heteroatoms/oxygen vacancies co-regulated γ-NiOOH may potentially obtain the optimal M-O covalency bonds, further simultaneously activating the metal sites and lattice oxygen. In this work, the NiMoO₄·xH₂O serves as the pre-catalyst, while Fe doped Ni 2 P nanoparticles deriving from the Prussian blue analogue (NiFe-PBA) are introduced to optimize the electron configuration of Ni sites in NiMoO 4 , thereby accelerating the deep reconstruction into the Fe atom/oxygen vacancies co-modified γ-NiOOH active phase (O V -Ni(Fe)OOH) during the electrochemical activation. A series of characterizations, including in-situ 18 O isotope-labeling differential electrochemical mass spectrometry (DEMS), in-situ surface-enhanced infrared absorption spectroscopy with attenuated total reflection (ATR-SEIRAS), and chemical probe is employed to confirm the compatible pathway of AEM and LOM in the activated catalyst. Furthermore, the experiment details and density functional theory (DFT) analysis unveil that Fe dopants significantly increases the lattice oxygen activity, while the proper concentration of O V regulate the Ni-O covalency bonds and optimize the AEM kinetics. Benefiting from the AEM-LOM coupled mechanism and the excellent mass transfer ability, the reconstructed OER catalyst in alkaline freshwater and seawater delivers 1.0 A cm − 2 current density at 275 and 299 mV, respectively. Moreover, the anion exchange membrane (AEM) water electrolyzer system assembled with Fe-Ni 2 P/NiMoO 4 and MoNi 4 exhibits preeminent durability in the successive ampere-level seawater electrolysis for 480 h. Results Design and structural characterizations of pre-catalysts Nanorod-like Fe-Ni 2 P/NiMoO 4 arrays, as the pre-catalysts, were directly grown on the nickel foams (NF) via hydrothermal, ion-exchange, and low-temperature phosphating methods as illustrated in Fig. 1 a and Supplementary Fig. 1. The composition and crystal structure of the products during the synthesis process was identified via X-ray diffraction (XRD). In Fig. 1 b and Supplementary Fig. 2, the characteristic peaks ascribing to NiMoO 4 ·xH 2 O (PDF#024-7435) constantly persist in the diffraction patterns of NiMoO 4 , PBA@NiMoO 4 , and Fe-Ni 2 P/NiMoO 4 , indicating that the NiMoO 4 ·xH 2 O phase is well-preserved. Significantly, the characteristic peaks of NiFe-PBA (K 2 FeNi(CN) 6 , PDF#023–0491) completely vanish after the low-temperature phosphating, while the new peaks at 41.1, 43.5, 47.7, and 53.7° that can be indexed to Ni 2 P (PDF#074-1385) in Fe-Ni 2 P/NiMoO 4 . Due to the absence of angle shift, Fe atoms are present in the Ni 2 P lattice as substitutional dopants, rather than interstitial dopants. The scanning electron microscope (SEM) was manipulated to observe the geometry morphology of samples. The arrays composed of NiMoO 4 ·xH 2 O nanorods possessing smooth surface are evenly grown on the NF frame (Supplementary Fig. 3). Following ion-exchange process, NiFe-PBA nanocubes cover the surface of nanorods, forming a unique top-hollow structure (Supplementary Fig. 4). As depicted in Supplementary Fig. 5 and Fig. 1 c, d, array and top-hollow configuration are retained, while the PBA nanocubes undergo melting and coalesce to form a continuous shell layer encapsulating the nanorods. This morphology is advantageous for accelerating reaction kinetics and enhancing mass transfer. Notably, we found that the dosage of C 6 H 5 Na 3 O 7 and NaH 2 PO 2 ·H 2 O has been identified as crucial factors in the synthesis and morphology control of the electrocatalysts (Supplementary Figs. 6–8). Experimental results demonstrate that the absence of C 6 H 5 Na 3 O 7 is detrimental to the growth of NiFe PBA on the surface of NiMoO 4 ·xH 2 O. Conversely, increasing the amount of C 6 H 5 Na 3 O 7 from 1.2 to 2.4 mmol gives rise to the disappearance of top-hollow configuration in the as-synthesized materials. Similarly, the phosphating process of NiFe-PBA is incomplete when the amount of NaH 2 PO 2 ·H 2 O is 0.9 g. However, increasing the dosage of phosphorus source to 2.7 g also results in the loss of the top-hollow structure. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) were employed to investigate the detailed geometric and phase structure of Fe-Ni 2 P/NiMoO 4 composite. In Fig. 1 e, the hierarchical nanorod structure composed of PBA derivative and NiMoO 4 ·xH 2 O is in good accordance with SEM images. HRTEM image obtained from the exposed interior of the nanorod reveals an interplanar parameter of 0.214 nm, which can be indexed to the (111) facet for Ni 2 P. Above observation aligns with the results of the XRD pattern. We employed the focused ion been (FIB) treatment to expose the cross-section of the Fe-Ni 2 P/NiMoO 4 composite, and the corresponding TEM and HRTEM images are presented in Fig. 1 f, Supplementary Figs. 9 and 10. The hierarchical configuration, comprising the amorphous layer, Fe-Ni 2 P nanoparticles, and NiMoO 4 ·xH 2 O core, can be distinctly visualized. Furthermore, the magnified high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image, corresponds to the region of NiMoO 4 ·xH 2 O core (Fig. 1 g). Two labeled crystal lattices with measured interplanar distances of 0.284 and 0.306 nm are identified, which correspond to the to (02 − 1) and (20 − 1) planes of NiMoO 4 ·xH 2 O, respectively (Supplementary Fig. 11). Based on the angular and lattice spacing relationships intrinsic to the anorthic system, the theoretical angle between the [02 − 1] and [20 − 1] crystal orientations is calculated to be 91°, which aligns well with the measurement (as illustrated in the inset of Fig. 1 g). The high crystallinity of NiMoO 4 ·xH 2 O within the composite is collectively confirmed via above results. Energy-dispersive X-ray spectroscopy (EDS) surface and line scans confirm that exclusively found in the core region is the Mo element, while Fe and P elements are predominantly present on the shell (Supplementary Figs. 12 and 13). Notably, as shown in Fig. 1 h-m, the larger mapping area of Ni element (compared to Mo element) in the cross-section of composite, belonging to Fe-Ni 2 P, demonstrates the tight binding between Fe-Ni 2 P and NiMoO 4 ·xH 2 O, which is conducive to electron transfer within two phases, thereby optimizing the electron configuration of Ni sites and accelerating the reconstruction process. To elucidate the role of each individual component within the composite catalyst system, we synthesized the Fe-doped Ni 2 P (marked as Fe-Ni 2 P) derived from NiFe-PBA on the NF using the same method. The XRD patterns, SEM images, and EDS mapping are presented in Supplementary Figs. 14–16. Then, the electronic structures of Fe-Ni 2 P/NiMoO 4 , Fe-Ni 2 P, and NiMoO 4 were analyzed by X-ray photoelectron spectroscopy (XPS) (Supplementary Fig. 17). For the high-resolution Ni 2 p spectrum of Fe-Ni 2 P/NiMoO 4 composite (Supplementary Fig. 17b), the deconvoluted peaks at 856.2 and 874.0 eV corresponding to Ni 2+ species exhibits a negative shift in comparison with pure Fe-Ni 2 P and a positive shift compared to pristine NiMoO 4 . The Fe 2 p spectrums in Fe-Ni 2 P/NiMoO 4 and Fe-Ni 2 P reveal the characteristic signal of Fe 2+ and Fe 3+ . Specifically, the significant positive shift in the bonding energy of the Fe 3+ peaks indicates that the Fe species in Fe-Ni 2 P/NiMoO 4 composite possess a higher oxidation state in contrast to that of Fe-Ni 2 P. These results reveal that the interaction between Fe-Ni 2 P and NiMoO 4 modulates the electronic structure of Ni in NiMoO 4 , concomitantly enhances the overall oxidation state of Fe sites, thereby increasing the conductivity and accelerating the deep reconfiguration process of pre-catalyst. The depth-profile XPS spectra (Supplementary Fig. 18) illustrates that the signal associated with the Ni-P peaks evolves with the increasing of etch level. This observation unveils that Fe-Ni 2 P predominantly concentrated within the interior of the nanorods, which quite agrees with the cross-sectional TEM results. Electrochemical activation of active phases As presented in Supplementary Figs. 19 and 20, the optimization process of current density and potential in the cyclic voltammetry (CV) and chronopotentiometry (CA) measurements, respectively, reveals the dynamic reconstruction and active phases generation of the pre-catalysts for pristine NiMoO 4 and Fe-Ni 2 P/NiMoO 4 . It is apparent that Fe-Ni 2 P/NiMoO 4 electrocatalyst possesses faster reconfiguration kinetics with augmented charge transfer capability by reason of the modification of Fe-Ni 2 P species. To explore the dynamic reconstruction of pre-catalysts in OER conditions, in-situ electrochemical and spectroscopy characterizations were employed. Firstly, we used the in-situ electrochemical impedance spectroscopy (in-situ EIS) to study the OER kinetics and electrocatalyst/electrolyte interface. The low-frequency region (10 − 2 − 10 1 Hz) of the impedance spectra corresponds to charge transfer between active species and OER intermediates, while the high-frequency region (10 1 − 10 4 Hz) reflects electron transfer procedures of the catalyst inner during the electrooxidation reaction 22 . As displayed in Supplementary Fig. 21 of Bode plots, the phase angle (θ) in the high-frequency region gradually decreases with the increasing applied potentials, wherein the Fe-Ni 2 P/NiMoO 4 possesses the smallest switched potential at 1.38 V vs. RHE, lower than that of NiMoO 4 (1.41 V vs. RHE) and Fe-Ni 2 P (1.41 V vs. RHE), indicating that the interaction between Fe-Ni 2 P and NiMoO 4 accelerates the generation of active phase. Then, the phase-evolution process of pre-catalysts was identified by in-situ Raman spectra with controlled applied potentials (Fig. 2 a and Supplementary Fig. 22). As the progressing of electro-oxidation process, the characteristic bands of Mo-O and Mo = O vibrations at 347, 825, 875, and 950 cm − 1 gradually abate and eventually disappear, ascribing to MoO 4 2− leaching under OER conditions. Especially, the typical active specie of γ-NiOOH can be confirmed by the presence of two characteristic peaks at 472 and 552 cm − 1 corresponding to E g and A 1g vibration modes for Ni 3+ -O, respectively 23 . Significantly, the conversion of Fe-Ni 2 P/NiMoO 4 to γ-NiOOH occurs at the lower potential (1.40 V), further demonstrating a faster electrochemical reconstruction. Following the electrochemical activation process, we obtained the reconstructed catalysts (labeled as R-*). We then further analyzed their crystalline, geometric, and electronic structures to elucidate the underlying mechanisms contributing to AEM-LOM dual-path. The XRD pattern of R-Fe-Ni 2 P/NiMoO 4 (Supplementary Fig. 23) manifests that the characteristic peaks of NiMoO 4 ·xH 2 O completely disappear, replaced by two new peaks located at 35.0 and 61.1°, which can be indexed to the (101) and (310) facets of NiOOH (PDF#027–0956). This transformation is also observed in the XRD pattern of R-NiMoO 4 . Besides, three weak peaks located at 41.1, 47.8, and 54.6° in R-Fe-Ni 2 P/NiMoO 4 are attributed to residual Ni 2 P species, which maintain the high conductivity of the whole catalyst. In Ni-(oxy)hydroxides, the ratio for bending and stretching vibration modes intensity (I B /I S ) can function as an indicator of disorder level, in which the lower I B /I S value represents the higher disorder structure 24 . As profiled in Supplementary Fig. 24, the I B /I S value for R-Fe-Ni 2 P/NiMoO 4 is measured at 1.37, contrasting sharply with the 2.16 value found in R-NiMoO 4 , indicating that Fe species from Fe-Ni 2 P migrate into the lattice of restructured NiOOH during electrochemical activation, resulting in a low crystallinity structure. SEM (Fig. 2 b, c) and TEM (Supplementary Fig. 25) images reveal that the 3D morphology of nanorod arrays is preserved in the reconstructed electrocatalyst, but the individual nanorods have evolved into a loose and porous structure. As shown in the HRTEM images (Fig. 2 d, e), the interplanar distance of 0.249 nm corresponds to the (101) facet of γ-NiOOH, aligning to the result of XRD pattern. Notably, discontinuous lattice fringes are present in the materials (the yellow circle highlight in Fig. 2 d), ascribing to the defects via the incorporation of O V . The EDS surface and line scans, as presented in Fig. 2 f-k and Supplementary Fig. 26, demonstrate a uniform distribution of the Fe element throughout the entire nanorod, rather than a concentration in the shell, indicating the introduction of Fe dopants into the whole active phase. Whilst, the marked decrease in the mapping intensity of Mo and P elements, as observed, originates to the leaching of MoO 4 2− and P species under OER conditions. These results confirm that O V -Ni(Fe)OOH is the real active specie in R-Fe-Ni 2 P/NiMoO 4 . XPS analysis is applied to explore the surface oxidation state changes between pre- and post-catalysts, as well as the differences in the electronic structure environment between reconstructed products. As illustrated in Supplementary Fig. 27, the proportion of Ni 3+ and Fe 3+ of R-Fe-Ni 2 P/NiMoO 4 exhibits a notable increasing compared to the initial Fe-Ni 2 P/NiMoO 4 . Meanwhile, the XPS signals related to Mo element and Ni-P bond almost disappear, corresponding to the leaching of MoO 4 2− and the reconstruction of Fe-Ni 2 P during the electrochemical activation. These results are consistent with XRD, Raman spectroscopy, and EDS mapping, further confirming the efficient and deep transformation during activation. It is noteworthy that the proportion of O V in the O 1 s spectrum slightly increases from 28.08–30.98% after reconstruction (Supplementary Table 1). The electron paramagnetic resonance (EPR) spectra (Supplementary Fig. 28a) also provide evidence of the appropriate increase in O V , which is conducive to optimizing the AEM kinetics. In Ni 2 p spectrum (Fig. 2 l), we found that the signal peaks of Ni 2 p 3/2 orbital for R-Fe-Ni 2 P/NiMoO 4 center between those of R-Fe-Ni 2 P and R-NiMoO 4 , illustrating that Fe dopants and O V primarily act as electron acceptors and donors, respectively, and co-modulate the electronic structure of Ni-(oxy)hydroxide. Meanwhile, as presented in Fig. 2 m, the peaks of lattice oxygen (M-O) for R-Fe-Ni 2 P/NiMoO 4 and R-Fe-Ni 2 P significantly shift toward the higher binding energy relative to that of R-NiMoO 4 , unveiling the enhanced Ni-O covalent bands and lattice oxygen activity following the introduction of Fe species 25 . Moreover, the slight increasing of O V has been also detected in the XPS and EPR spectra of R-NiMoO 4 (Fig. 2 m and Supplementary Fig. 28c), indicating that MoO 4 2− and crystalline water co-leaching is the primary reason for the generation of O V in NiMoO 4 system 26 . The binding energy of Fe 2 p peak for R-Fe-Ni 2 P/NiMoO 4 exhibits a significant negative-shift with respect to that of R-Fe-Ni 2 P (Fig. 2 n) indicates that the over-oxidation of Fe species in active phases has been suppressed, which is favorable to circumvent the Fe leaching thus pacifying lattice oxygen 27 . The absence of P and Mo element signals is also observed in Supplementary Fig. 29 for XPS spectra of R-Fe-Ni 2 P and R-NiMoO 4 , respectively. Electrocatalytic OER performance We assembled a typical three-electrode system, directly employing the pre-catalysts or benchmarks as the work electrode to test their electrocatalytic performance in O 2 -saturated 1 M KOH. The activated Fe-Ni 2 P/NiMoO 4 catalyst exhibits the optimal OER performance (as seen in Fig. 3 a), delivering current densities of 10, 100, 500, and 1000 mA cm − 2 at 197, 221, 251, and 275 mV, respectively, which is in excess of other counterparts. Fe-Ni 2 P/NiMoO 4 exerts the lowest Tafel slope (30.51 mV dec − 1 ), as described in Supplementary Fig. 30, suggesting the superior OER reaction kinetics. Simultaneously, Fe-Ni 2 P/NiMoO 4 also presents the accelerated charge-transfer capacity, featuring the optimal charge transfer resistance (R ct ) of 0.77 Ω, lower than that of Fe-Ni 2 P (2.91 Ω), NiMoO 4 (1.55 Ω), and RuO 2 (12.61 Ω) in Supplementary Fig. 31 and table 2. Moreover, the electrochemical surface area (ECSA) and turnover frequency (TOF) were calculated to assess the intrinsic OER activity (Supplementary Figs. 32 and 33). Apparently, Fe-Ni 2 P/NiMoO 4 displays the maximum ECSA-normalized current density and TOF value. In summary, the systematic comparison of OER activity, Tafel slope, R ct , C dl , and TOF is presented in Fig. 3 b, and the comprehensive OER performance for Fe-Ni 2 P/NiMoO 4 outperforms that of all control samples. Compared with recently reported OER catalysts (Fig. 3 c), Fe-Ni 2 P/NiMoO 4 demonstrates the immense prospect for application, especially under ampere-level current densities. Following that, we measured the OER efficiency of catalysts in 1 M KOH + 0.5 M NaCl and 1 M KOH + seawater solution. In Fig. 3 d and e, Fe-Ni 2 P/NiMoO 4 exhibits low overpotentials of 296 and 299 mV at 1000 mA cm − 2 current density in alkaline artificial and natural seawater, respectively, accompanied by low Tafel slopes (36.14 and 39.64 mV dec − 1 ). The performance of Fe-Ni 2 P/NiMoO 4 significantly surpasses that of control samples and the state-of-art catalysts (Fig. 3 f), further demonstrating its underlying application value. Notably, the R ct of NiMoO 4 discernibly increases from 3.21 to 7.89 Ω when the electrolyte is switched from simulated seawater to real seawater, whereas Fe-Ni 2 P/NiMoO 4 and Fe-Ni 2 P exhibit slight degradation (Fig. 3 g and Supplementary Table 3 to 4). Meanwhile, as illustrated in the Tafel corrosion plots and derived corrosion data (Fig. 3 g and Supplementary Table 5), Fe-Ni 2 P/NiMoO 4 possess higher corrosion potential at -0.214 V vs. SCE accompanied by lower current density of 0.124 mA cm − 2 , as compared with Fe-Ni 2 P and initial NiMoO 4 . These results reveal that the negligible decay in natural seawater solution, compared with that in freshwater and simulated seawater, attributes the high intrinsic activity and the presence of amorphous protective layer, which effectively circumvents the ClER and mitigates the impact of impurities. Fe-Ni 2 P/NiMoO 4 shows the satisfactory long-term durability at 1.0 A cm − 2 for 100 h in both alkaline freshwater and seawater (Fig. 3 i), confirming that the participation of AEM pathway suppresses the damage to stability induced by LOM. Meanwhile, the residual chlorine detection (Supplementary Fig. 34) demonstrates that no ClO − was generated during the seawater oxidation process. The absence of ClER leads to a commendable Faraday efficiency of 98.26% in alkaline seawater, which is remarkably close to the results obtained in alkaline freshwater (98.45%) (Supplementary Figs. 35–37). AEM-LOM dual-path OER mechanism analysis We further explore the activation conditions of the dual-path OER mechanism involved in Fe-Ni 2 P/NiMoO 4 . As profiled in Supplementary Fig. 38, the OER activity under different pH values was used to preliminarily determine the pathway of the activated electrocatalysts. Generally, a close association exists between the pH dependence and the proton-reaction order (ρ), with a ρ value closed to 1 manifesting a non-concerted proton-electron transfer pathway 55 . Therefore, Fe-Ni 2 P/NiMoO 4 , NiMoO 4 , and Fe-Ni 2 P catalysts may undergo the LOM pathway (Fig. 4 a). Notably, the strongest pH-dependence of Fe-Ni 2 P/NiMoO 4 at 1.55 V vs. RHE suggests that it possesses the higher lattice oxygen activity at a lower potential. Furthermore, O 2 signal released by the 18 O isotope-labeled Fe-Ni 2 P/NiMoO 4 during OER process in H 2 16 O was captured via in-situ DEMS to analyze the OER mechanism. As shown in Fig. 4 b, mass spectrometer detected distinct signals of 16 O 16 O and 16 O 18 O gas, corresponding to the O 2 products from AEM and LOM pathway, respectively 56 . Meanwhile, the absence of significant 18 O 18 O signal suggests that only one lattice oxygen participates in the reaction. In addition, in-situ ATR-SEIRAS was manipulated to detect the interplay between oxygen-containing intermediates and the catalytic surface during OER process. In Fig. 4 c, two distinct peaks are observed in the range from 1000 to 1200 cm − 1 , which emerged with the increasing of applied potentials. The one centered at 1052 cm − 1 can be indexed to the *OOH intermediate generated from AEM pathway, while the vibration of O-O in the characteristic intermediate from LOM can be discovered at 1211 cm − 1 , synthetically demonstrating the compatible mechanism of both AEM and LOM in Fe-Ni 2 P/NiMoO 4 57,58 . To distinguish in detail the contributions of each component in the Fe-Ni 2 P/NiMoO 4 composite to OER mechanism, chemical probes were employed to detect the forms and chemical properties of oxygenated intermediates on the catalyst surface. Methanol is known to compete for *OH intermediate adsorption on the catalyst surface under electrooxidation conditions. Consequently, methanol oxidation reaction (MOR) serves as a diagnostic measurement to evaluate *OH adsorption behavior, with MOR current density exhibiting a direct positive correlation with *OH surface coverage 59 . As depicted in Fig. 4 d, Fe-Ni 2 P/NiMoO 4 and NiMoO 4 exhibit significantly higher MOR current densities than Fe-Ni 2 P at equivalent potentials, indicating more efficient and unimpeded *OH adsorption due to the introduction of O V . Furthermore, the moderate enhancement of MOR current densities relative to the OER activity in Fe-Ni 2 P/NiMoO 4 suggests that Fe species and O V in the active phase jointly optimize the *OH adsorption energy and deprotonation kinetics in the AEM pathway. Similarly, tetramethylammonium cation (TMA + ) competitively adsorbs the characteristic intermediate (peroxide, O 2 2− ) in the LOM pathway due to the strong electrostatic interaction, hindering the OER process dominated by LOM 8 . The negligible decrease of OER performance for NiMoO 4 in Fig. 4 e, suggests that R-NiMoO 4 primarily follows the AEM pathway. Conversely, Fe-Ni 2 P/NiMoO 4 and Fe-Ni 2 P exhibit marked deterioration in OER activity and kinetics, indicating that Fe doping induces the activation of oxygen ligands in active phases. DFT calculation was employed to obtain deeper understanding of the electron configuration and OER mechanism. We constructed the theoretical structure models of the real active species for NiOOH, Ni(Fe)OOH, and O V -Ni(Fe)OOH (Supplementary Fig. 39). Based on the analysis for density of states (DOS), the Ni 3 d band center in O V -Ni(Fe)OOH (-2.921 eV) shifts upward toward the Fermi level (E F ) with respect to Ni(Fe)OOH (-2.993 eV) and NiOOH (-3.043 eV) (Fig. 4 f). This result indicates the Ni sites in O V -Ni(Fe)OOH is more conductive to donate electrons, beneficial for increasing the proportion of AEM pathway in OER procedures. Additionally, the higher orbital overlap of Ni 3 d and O 2 p above E F suggests a stronger interaction between metal sites and oxygen ligands. Apparently, the rank of DOS overlap degree is Ni(Fe)OOH > O V -Ni(Fe)OOH > NiOOH (as depicted in Fig. 4 f). This observation, consistent with the XPS spectra results (Fig. 2 l, m), implies the moderate Ni-O covalency for O V -Ni(Fe)OOH under the co-modulation of Fe species and O V , providing the prerequisite for triggering AEM-LOM dual-path. The Gibbs free energy was computed to demonstrated the optimal active sites for AEM and LOM in O V -Ni(Fe)OOH (Supplementary Figs. 40–42). As shown in Fig. 4 g, the deprotonation process (*OH → *O) on both Ni and Fe sites is identified as rate-determining step (RDS), wherein the energy barrier on Ni site is optimized to 2.20 eV. Considering the strong redox activity of Ni sites in O V -Ni(Fe)OOH, Ni atoms may preferentially adsorb the OH − , further coupling with oxygen ligands in matrix after deprotonation, which follows the single-metal-site mechanism (SMSM), rather than the oxygen-vacancy-site mechanism (OVSM) (Supplementary Fig. 43). Consequently, we simulated the energy barriers of the LOM pathway under OVSM and SMSM. As presented in Fig. 4 h, the RDS of O site exhibits the optimal Gibbs free energy difference (ΔG) of 1.98 eV, indicating that O V -Ni(Fe)OOH follows the OVSM. Furthermore, comparing the theoretical overpotentials of AEM (0.97 V) and LOM (0.75 V) reveals the AEM is inclined to occur at higher potentials. This is advantageous for circumventing the structural collapse induced by the LOM pathway at high current densities, thereby obtaining the promising OER catalyst together with activity and stability. Freshwater/seawater splitting performance Given the remarkable efficiency and durability of Fe-Ni 2 P/NiMoO 4 for electrocatalytic freshwater/seawater oxidation, the activated Fe-Ni 2 P/NiMoO 4 electrode was employed as the anode, while the as-prepared MoNi 4 HER catalyst served as cathode, to construct an OWS electrolyzer for evaluating the application potential at industrial conditions. The MoNi 4 || Fe-Ni 2 P/NiMoO 4 electrode-pair can reduce the cell voltages to 1.784 and 1.798 V in alkaline freshwater and seawater (Fig. 5 a), respectively, which competent to drive a current density of 1.0 A cm − 2 at room temperature. It is noted that the OWS performance of MoNi 4 || Fe-Ni 2 P/NiMoO 4 surpasses that of benchmarked electrocatalysts pair (Pt/C || RuO 2 ), which requires 2.299 V (alkaline freshwater) and 2.413 V (alkaline seawater). Furthermore, after 100 h of continuous freshwater/seawater splitting at ampere-scale constant current density, the MoNi 4 || Fe-Ni 2 P/NiMoO 4 system exhibits slight performance degradation, underscoring its excellent durability. Moreover, as shown in Supplementary Fig. 44, a piece of solar cell sheet can drive OWS in the MoNi 4 || Fe-Ni 2 P/NiMoO 4 system, featuring continuous bubble release of hydrogen and oxygen on the catalytic surface. This result validates the application potential of Fe-Ni 2 P/NiMoO 4 in the renewable energy conversion. The anion exchange membrane (AEM) natural seawater electrolyzer using Fe-Ni 2 P/NiMoO 4 and MoNi 4 electrocatalyst as anode and cathode, respectively, was assembled to simulate the electrocatalytic hydrogen production process in the industrial application. The geometric area of both anode and cathode was 1 × 1 cm 2 , while the exchange membrane was tailored to 3 × 3 cm 2 . As illustrated in the j -V curves (Fig. 5 c), MoNi 4 || Fe-Ni 2 P/NiMoO 4 electrolyzer exhibits superior AEM alkaline seawater splitting activity at 25°C, achieving 2.616 V cell voltage to reach 1.0 A cm − 2 , which surpasses that of benchmarked Pt/C || RuO 2 pair (3.322 V at 1.0 A cm − 2 ). Notably, the MoNi 4 || Fe-Ni 2 P/NiMoO 4 AEM system maintained steady seawater electrolysis for 480 h at ampere-level current density (Fig. 5 d), highlighting its long-term durability for industrial application. Discussion To sum up, we designed Fe-Ni 2 P decorated NiMoO 4 hydrate (Fe-Ni 2 P/NiMoO 4 ) as a pre-catalyst with optimized electron configuration, thereby expediting the deep reconfiguration into O V -Ni(Fe)OOH active phase. XPS analysis reveals that the Fe species and O V synergistically regulate the electronic structure of NiOOH, providing proper covalency of Ni-O bonds for simultaneously triggering metal sites and oxygen ligands. In-situ 18 O isotope-labeling DEMS, in-situ ATR-SEIRAS, chemical probe experiments and DFT calculations confirm the AEM-LOM dual-path OER mechanism with optimized intermediates adsorption energy for O V -Ni(Fe)OOH. Consequently, the activated Fe-Ni 2 P/NiMoO 4 catalyst demonstrates commendable OER activity. It features 275 and 299 mV overpotentials to drive the ampere-level freshwater and seawater oxidation, respectively, with the negligible activity decay for 100 h of continuous electrocatalysis in tree-electrode cell. Furthermore, as-prepared Fe-Ni 2 P/NiMoO 4 electrode, when employed as the anode in an AEMWE system, achieving continuous ampere-level seawater electrolysis for 480 h at 1.0 A cm − 2 . Methods Materials Nickel nitrate hexahydrate (Ni(NO 3 ) 2 ·6H 2 O), potassium ferricyanide (K 3 Fe(CN) 6 ), trisodium citrate (C 6 H 5 Na 3 O 7 ), sodium hypophosphite (NaH 2 PO 2 ·H 2 O), ammonium molybdate tetrahydrate ((NH 4 ) 6 Mo 7 O 24 ), ruthenium dioxide (RuO 2 ), carbon-supported platinum (Pt/C, 20 wt.%), potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAOH) were sourced from Aladdin. Absolute ethanol, acetone, isopropanol, and hydrochloric acid were sourced from Zhisheng. All chemical reagents employed in this study were of purity exceeding analytical grade and utilized directly without undergoing any additional purification procedures. In the process of solution formulation, deionized (DI) water was exclusively used as the solvent to ensure consistent experimental conditions. We collected natural seawater from the Bohai sea in Hebei Province, China, and used after filtering. Preparation of Fe-Ni 2 P/NiMoO 4 Nikel foam (NF) was tailored to 3 × 4 cm 2 and rinsed by ultrasonication in acetone, diluted hydrochloric acid, absolute ethanol, and DI water, to eliminate the oils and oxides. To synthesis nickel molybdate hydrate (NiMoO 4 ·xH 2 O), Ni(NO 3 ) 2 ·6H 2 O and (NH 4 ) 6 Mo 7 O 24 (molar ratio 4:1) with 60 mL of DI water were poured into the 100 mL Teflon-lined receptacle, and a homogeneous solution was obtained after continuous stirring for at least 15 min. Then, the receptacle was sealed into a stainless-steel autoclave and kept at 150°C for 6 h. Once cooled to room temperature, the product was repeatedly rinsed with DI water and absolute ethanol three times and dried in a vacuum oven at 60°C for 12 h. Then, the as-prepared NiMoO 4 ·xH 2 O was immersed in the 40 mL aqueous solution hybrid containing 20 mL solution A (0.8 mmol Ni(NO 3 ) 2 ·6H 2 O and a certain dosage of C 6 H 5 Na 3 O 7 ) and 20 mL solution B (0.5 mmol K 3 Fe(CN) 6 ) for 26 h at room temperature to obtain PBA@NiMoO 4 . Finally, a certain amount of NaH 2 PO 2 ·H 2 O was accurately weighed and put in an alumina ceramic container together with PBA@NiMoO 4 . Placing the container in the central position of the quartz tube, wherein PBA@NiMoO 4 located at the downstream of argon flow. We obtained the Fe-Ni 2 P/NiMoO 4 after two-hour low-temperature phosphorization process at 300°C. The preparation methods for counterparts and benchmarked catalysts can be found in the Supplementary Text. Declarations Data availability In the main manuscript or the supplementary materials, all employed data are available. Acknowledgements The authors acknowledge the financial support from the National Natural Science Foundation of China (Grant No. 21371149, 21671168) and the financial support from the Natural Science Foundation of Hebei Province (Grant No. B2021203016, 22281403Z), S&T Program of Hebei (236Z4405G) and Hebei Youth Top-notch Talent Support Program. The authors thank the subsidy for Hebei Key Laboratory of Applied Chemistry after Operation Performance (22567616H). Author contributions X.W. conducted most experiments and data analysis. X.Y. and J.J. helped with HAADF-STEM and TEM measurements. H.N. assisted in electrochemical measurements. L.H. and F.M. oversaw the project and assisted in data analysis. The final version of the text has been carefully reviewed and approved by all authors for submission. Competing interests All authors report no competing interests. References Huang W et al (2022) Ligand modulation of active sites to promote electrocatalytic oxygen evolution. Adv Mater 34:2200270 Cai Z et al (2022) Reinforced layered double hydroxide oxygen-evolution electrocatalysts: a polyoxometallic acid wet‐etching approach and synergistic mechanism. Adv Mater 34:2110696 Wang T et al (2018) NiFe (Oxy) hydroxides derived from NiFe disulfides as an efficient oxygen evolution catalyst for rechargeable Zn-air batteries: the effect of surface S residues. Adv Mater 30:1800757 Chen L et al (2024) Seawater electrolysis for fuels and chemicals production: fundamentals, achievements, and perspectives. Chem Soc Rev 53:7455–7488 Wang A et al (2023) Enhancing oxygen evolution reaction by simultaneously triggering metal and lattice oxygen redox pair in iridium loading on Ni-doped Co 3 O 4 . Adv Energy Mater 13:2302537 Dionigi F et al (2020) In-situ structure and catalytic mechanism of NiFe and CoFe layered double hydroxides during oxygen evolution. Nat Commun 11:2522 Song J et al (2020) A review on fundamentals for designing oxygen evolution electrocatalysts. Chem Soc Rev 49:2196–2214 Huang Z et al (2021) Tuning of lattice oxygen reactivity and scaling relation to construct better oxygen evolution electrocatalyst. Nat Commun 12:3992 Xie X et al (2022) Oxygen evolution reaction in alkaline environment: material challenges and solutions. Adv Funct Mater 32:2110036 Zhang G et al (2024) Selective activation of lattice oxygen site through coordination engineering to boost the activity and stability of oxygen evolution reaction. Angew Chem Int Ed 63:e202407509 Lin C et al (2021) In-situ reconstructed Ru atom array on α-MnO 2 with enhanced performance for acidic water oxidation. Nat Catal 4:1012–1023 Wang Z, Goddard III, W. A., Xiao H (2023) Potential-dependent transition of reaction mechanisms for oxygen evolution on layered double hydroxides. Nat Commun 14:4228 Xin S et al (2023) Coupling adsorbed evolution and lattice oxygen mechanism in Fe-Co(OH) 2 /Fe 2 O 3 heterostructure for enhanced electrochemical water oxidation. Adv Funct Mater 33:2305243 Liu X et al (2020) Complete reconstruction of hydrate pre-catalysts for ultrastable water electrolysis in industrial-concentration alkali media. Cell Rep Phys Sci 1:100241 Dürr RN et al (2021) From NiMoO 4 to γ-NiOOH: detecting the active catalyst phase by time resolved in situ and operando Raman spectroscopy. ACS Nano 15:13504–13515 Li J et al (2018) Low-crystalline bimetallic metal-organic framework electrocatalysts with rich active sites for oxygen evolution. ACS Energy Lett 4:285–292 Huang Y, Wang Z, Xiao H, Liu Q, Wang X (2024) Activating and stabilizing lattice oxygen via self-adaptive Zn-NiOOH sub-nanowires for oxygen evolution reaction. J Am Chem Soc 146:29006–29016 Zhang Y et al (2024) Activating lattice oxygen based on energy band engineering in oxides for industrial water/saline oxidation. Energy Environ Sci 17:3347–3357 Fan W et al (2024) Biomimetic Stylophora pistillata-like NiMoO 4 /NiFeS crystalline-amorphous phase boundary activated lattice oxygen mechanism for efficient electrochemical water oxidation. Chem Eng J 502:158106 Zhu J, Qian J, Peng X, Xia B, Gao D (2023) Etching-induced surface reconstruction of NiMoO 4 for oxygen evolution reaction. Nano-Micro Lett 15:30 Jiang R et al (2024) Redox promoted rapid and deep reconstruction of defect-rich nickel precatalysts for efficient water oxidation. Small 20:2401384 Lyons ME, Doyle RL, Brandon MP (2011) Redox switching and oxygen evolution at oxidized metal and metal oxide electrodes: iron in base. Phys Chem Chem Phys 13:21530–21551 Zhu K, Zhu X, Yang W (2019) Application of in situ techniques for the characterization of NiFe-based oxygen evolution reaction (OER) electrocatalysts. Angew Chem Int Ed 58:1252–1265 Huang J et al (2019) Identification of key reversible intermediates in self-reconstructed nickel‐based hybrid electrocatalysts for oxygen evolution. Angew Chem Int Ed 131:17619–17625 Ye P et al (2024) Lattice oxygen activation and local electric field enhancement by co-doping Fe and F in CoO nanoneedle arrays for industrial electrocatalytic water oxidation. Nat Commun 15:1012 Wang H et al (2024) Application progress of NiMoO 4 electrocatalyst in basic oxygen evolution reaction. Catal Sci Technol 14:533–554 Guan Xu H et al (2025) Oxygen plasma triggered Co-O-Fe motif in Prussian blue analogue for efficient and robust alkaline water oxidation. Angew Chem Int Ed 64:e202415423 Xu Z et al (2022) Metal-organic framework-derived 2D NiCoP nanoflakes from layered double hydroxide nanosheets for efficient electrocatalytic water splitting at high current densities. ACS Sustain Chem Eng 10:11577–11586 Zhang X et al (2022) In situ reconstructed Zn doped Fe x Ni (1–x) OOH catalyst for efficient and ultrastable oxygen evolution reaction at high current densities. Small 18:2203710 Liu S, Ren S, Gao R, Liu X, Wang L (2022) Atomically embedded Ag on transition metal hydroxides triggers the lattice oxygen towards sustained seawater electrolysis. Nano Energy 98:107212 Guo L et al (2023) Dual-doping NiMoO 4 with multi-channel structure enable urea-assisted energy-saving H 2 production at large current density in alkaline seawater. Appl Catal B-Environ 320:121977 Song Y et al (2023) Alleviating the work function of vein-like Co X P by Cr doping for enhanced seawater electrolysis. Adv Funct Mater 33:2214081 Zhou L, Huang Z, Kang F, Lv R (2023) Bimetallic substrate induction synthesis of binder-free electrocatalysts for stable seawater oxidation at industrial current densities. Chem Eng J 458:141457 Lv X et al (2023) Atomic-level surface engineering of nickel phosphide nanoarrays for efficient electrocatalytic water splitting at large current density. Adv Funct Mater 33:2205161 Zhang Y et al (2024) Stable tetravalent Ni species generated by reconstruction of FeB-wrapped NiMoO pre-catalysts enable efficient water oxidation at large current densities. Appl Catal B-Environ 341:123297 Yao Y et al (2024) Enhancing the stability of NiFe-layered double hydroxide nanosheet array for alkaline seawater oxidation by Ce doping. J Energy Chem 91:306–312 Yu Q et al (2024) MXene-mediated reconfiguration induces robust nickel-iron catalysts for industrial-grade water oxidation. P Natl Sci 121:e1975073175 Chen Y et al (2024) Boosting oxygen evolution reaction by FeNi hydroxide-organic framework electrocatalyst toward alkaline water electrolyzer. Nat Commun 15:7278 Luo X et al (2024) Fe-S dually modulated adsorbate evolution and lattice oxygen compatible mechanism for water oxidation. Nat Commun 15:8293 You H et al (2022) Monolayer NiIr-layered double hydroxide as a long-lived efficient oxygen evolution catalyst for seawater splitting. J Am Chem Soc 144:9254–9263 Luo X et al (2022) Spherical Ni 3 S 2 /Fe-NiP x magic cube with ultrahigh water/seawater oxidation efficiency. Adv Sci 9:2104846 Xu X et al (2023) Fe-doped and carbon composite multiphase hetero-structured catalysts based on the ion-exchange strategy for seawater electrolysis. ACS Sustain Chem Eng 11:15338–15349 Li M et al (2023) Synergetic regulation of CeO 2 modification and (W 2 O 7 ) 2– intercalation on NiFe-LDH for high-performance large-current seawater electrooxidation. Appl Catal B-Environ 330:122612 Wu D et al (2023) Fe-regulated amorphous‐crystal Ni(Fe)P 2 nanosheets coupled with Ru powerfully drive seawater splitting at large current density. Small 19:2300030 Malek A, Xue Y, Lu X (2023) Dynamically restructuring Ni x Cr y O electrocatalyst for stable oxygen evolution reaction in real seawater. Angew Chem Int Ed 135:e202309854 Andaveh R et al (2023) Boosting the electrocatalytic activity of NiSe by introducing MnCo as an efficient heterostructured electrocatalyst for large-current-density alkaline seawater splitting. Appl Catal B-Environ 325:122355 Li Z et al (2024) Carbon oxyanion self-transformation on NiFe oxalates enables long‐term ampere‐level current density seawater oxidation. Angew Chem Int Ed 63:e202316522 Kang X et al (2023) A corrosion-resistant RuMoNi catalyst for efficient and long-lasting seawater oxidation and anion exchange membrane electrolyzer. Nat Commun 14:3607 Zhang H et al (2023) Dense crystalline/amorphous phosphides/oxides interfacial sites for enhanced industrial-level large current density seawater oxidation. ACS Nano 17:16008–16019 Yu W et al (2024) Unique CoP microflower decorated with phosphorous-enriched PtP 2 onto nickel foam with interfacial electronic interactions to boost alkaline water‐splitting. Adv Funct Mater 34:2313935 He L et al (2024) Three-dimensional porous NiCoP foam enabled high-performance overall seawater splitting at high current density. J Mater Chem A 12:2680–2684 Shen X et al (2024) Construction of heterojunction-rich metal nitrides porous nanosheets electrocatalyst for alkaline water/seawater splitting at large current density. Small 20:2310535 Li J et al (2024) Highly anti-corrosive NiFe LDHs-NiFe alloy hybrid enables long-term stable alkaline seawater electrolysis. Rare Met 43:4321–4332 Guo L et al (2024) Phosphorus defect mediated electron redistribution to boost anion exchange membrane-based alkaline seawater electrolysis. Adv Energy Mater 14:2400975 Mefford JT et al (2016) Water electrolysis on La 1 – x Sr x CoO 3–δ perovskite electrocatalysts. Nat Commun 7:11053 Liu L et al (2024) Antagonism effect of residual S triggers the dual-path mechanism for water oxidation. J Energy Chem 93:568–579 Sivasankar N, Weare WW, Frei H (2011) Direct observation of a hydroperoxide surface intermediate upon visible light-driven water oxidation at an Ir oxide nanocluster catalyst by rapid-scan FT-IR spectroscopy. J Am Chem Soc 133:12976–12979 Hao Y et al (2023) Switching the oxygen evolution mechanism on atomically dispersed Ru for enhanced acidic reaction kinetics. J Am Chem Soc 145:23659–23669 Mei Y et al (2022) High-entropy alloy with Mo-coordination as efficient electrocatalyst for oxygen evolution reaction. ACS Catal 12:10808–10817 Additional Declarations There is NO Competing Interest. Supplementary Files Supporting20250401NatCom.docx Iron and oxygen vacancies co-modulated adsorption evolution and lattice oxygen dual-path mechanism for enhanced ampere-level freshwater/seawater oxidation Cite Share Download PDF Status: Published Journal Publication published 02 Oct, 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-6367775","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":441429873,"identity":"a2f0b448-ff76-4f08-b979-a31031cf69ca","order_by":0,"name":"Faming 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09:14:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6367775/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6367775/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41467-025-63844-x","type":"published","date":"2025-10-02T04:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":80515742,"identity":"50a2fb26-928d-4f3f-9357-187da5365f8e","added_by":"auto","created_at":"2025-04-14 08:03:11","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1586256,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePreparation scheme, and structural characterizations of the Fe-Ni\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003eP/NiMoO\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e pre-catalyst.\u003c/strong\u003e \u003cstrong\u003ea \u003c/strong\u003eDiagrammatic sketch presenting the fabrication procedure of the Fe-Ni2P/NiMoO4 composite, and the electrochemical reconstruction product. \u003cstrong\u003eb\u003c/strong\u003e XRD pattern for Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e. \u003cstrong\u003ec\u003c/strong\u003e SEM image. \u003cstrong\u003ed\u003c/strong\u003e Enlarged SEM image. \u003cstrong\u003ee\u003c/strong\u003e TEM, HRTEM images, and the corresponding intensity-distance images for the lattice\u0026nbsp;fringe. \u003cstrong\u003ef\u003c/strong\u003e The cross-sectional TEM image of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e. \u003cstrong\u003eg\u003c/strong\u003e The magnified HAAD-STEM image in the region of NiMoO\u003csub\u003e4\u003c/sub\u003e (inset: SAED pattern). \u003cstrong\u003eh\u003c/strong\u003e The cross-sectional HAAD-STEM image, and \u003cstrong\u003ei-m\u003c/strong\u003e corresponding EDS element mapping images.\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-6367775/v1/722d9bb99eab68d0aacb5391.png"},{"id":80516537,"identity":"5c42f1aa-94bb-4818-aab4-09c27eb91cf6","added_by":"auto","created_at":"2025-04-14 08:11:11","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":711653,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eElectrochemical activation and structural characterizations of activated catalysts.\u003c/strong\u003e \u003cstrong\u003ea \u003c/strong\u003eIn-situ Raman spectroscopy analysis of catalyst reconstruction for Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e. The geometric structure of activated catalyst for R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e. \u003cstrong\u003eb\u003c/strong\u003e SEM, \u003cstrong\u003ec\u003c/strong\u003e enlarged SEM, \u003cstrong\u003ed\u003c/strong\u003e HRTEM, and \u003cstrong\u003ee\u003c/strong\u003e enlarged HRTEM images. \u003cstrong\u003ef\u003c/strong\u003e The HAAD-STEM image of R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4 \u003c/sub\u003e(scale bar: 100 nm), and \u003cstrong\u003eg-k\u003c/strong\u003e corresponding EDS element mapping images. The electronic structure of activated catalysts. \u003cstrong\u003el\u003c/strong\u003e Ni 2\u003cem\u003ep\u003c/em\u003e, \u003cstrong\u003em\u003c/strong\u003e O 1\u003cem\u003es\u003c/em\u003e, and \u003cstrong\u003en\u003c/strong\u003e Fe 2\u003cem\u003ep\u003c/em\u003e high-resolution XPS spectra.\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-6367775/v1/f7df11bfd6cb7d3ce167694b.png"},{"id":80515748,"identity":"a4ad2a62-80df-487d-9261-ea75b75a6b63","added_by":"auto","created_at":"2025-04-14 08:03:11","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":843419,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe electrocatalytic performance of as-prepared electrocatalysts.\u003c/strong\u003e \u003cstrong\u003ea \u003c/strong\u003eOER LSV curves in 1 M KOH solution. \u003cstrong\u003eb\u003c/strong\u003e Comprehensive comparisons for OER performance, Tafel slopes, R\u003csub\u003ect\u003c/sub\u003e, C\u003csub\u003edl\u003c/sub\u003e, and TOF of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4 \u003c/sub\u003ewith other samples. \u003cstrong\u003ec\u003c/strong\u003e Comparison of the OER performance for recently reported electrocatalysts in alkaline freshwater\u003csup\u003e28-39\u003c/sup\u003e. \u003cstrong\u003ed\u003c/strong\u003e OER LSV curves in alkaline brackish water (solid) and alkaline real seawater (dot), and \u003cstrong\u003ee\u003c/strong\u003e corresponding Tafel slopes. \u003cstrong\u003ef\u003c/strong\u003e Comparison of the OER performance for recently reported electrocatalysts in alkaline seawater\u003csup\u003e40-54\u003c/sup\u003e. \u003cstrong\u003eg\u003c/strong\u003e Nyquist plots in different electrolytes. \u003cstrong\u003eh\u003c/strong\u003e Tafel plots for corrosion potentials in real seawater. \u003cstrong\u003ei\u003c/strong\u003e The durability measurements of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e at 1.0 A cm\u003csup\u003e-2\u003c/sup\u003e constant current density in different electrolytes.\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-6367775/v1/b72903dc9e10d5c78186fb61.png"},{"id":80515745,"identity":"79d303a9-7b8f-4988-93f4-74b2a214ac0c","added_by":"auto","created_at":"2025-04-14 08:03:11","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":677677,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDual-path OER mechanism exploration. a \u003c/strong\u003eThe pH dependence of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e, NiMoO\u003csub\u003e4\u003c/sub\u003e, and Fe-Ni\u003csub\u003e2\u003c/sub\u003eP measured from the logarithm of current densities at 1.55 V vs. RHE in different concentrations of KOH solution and corresponding pH values (12.5, 13.0, 13.5, and 14.0). \u003cstrong\u003eb\u003c/strong\u003e In-situ DEMS signals of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4 \u003c/sub\u003efor \u003csup\u003e16\u003c/sup\u003eO\u003csup\u003e16\u003c/sup\u003eO, \u003csup\u003e16\u003c/sup\u003eO\u003csup\u003e18\u003c/sup\u003eO, and \u003csup\u003e18\u003c/sup\u003eO\u003csup\u003e18\u003c/sup\u003eO related to testing time. \u003cstrong\u003ec\u003c/strong\u003e In-situ ATR-SEIRAS collected from 1.20 to 1.50 V vs. RHE for Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e. \u003cstrong\u003ed\u003c/strong\u003e OER LSV curves in 1 M KOH and 1 M KOH + CH\u003csub\u003e3\u003c/sub\u003eOH. \u003cstrong\u003ee\u003c/strong\u003e OER LSV curves measured in 1 M KOH and 1 M TMAOH, accompanied by the corresponding Tafel slopes. \u003cstrong\u003ef\u003c/strong\u003e Projected density of states (PDOS) for O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH, Ni(Fe)OOH, and NiOOH. The calculated OER free energy diagrams of the \u003cstrong\u003eg\u003c/strong\u003e AEM pathway, and \u003cstrong\u003eh\u003c/strong\u003e LOM pathway for different active sites in O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH.\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-6367775/v1/b2da22b49740bade355b4132.png"},{"id":80515743,"identity":"caad4fb9-cfa1-446f-8690-6b496b8ddbae","added_by":"auto","created_at":"2025-04-14 08:03:11","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":363535,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eWater electrolyzer performance. a \u003c/strong\u003eOWS LSV curves of MoNi\u003csub\u003e4\u003c/sub\u003e || Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4 \u003c/sub\u003eand Pt/C || RuO\u003csub\u003e2\u003c/sub\u003e. \u003cstrong\u003eb\u003c/strong\u003e The stability test of MoNi\u003csub\u003e4\u003c/sub\u003e || Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4 \u003c/sub\u003eat 1.0 A cm\u003csup\u003e-2\u003c/sup\u003e. \u003cstrong\u003ec\u003c/strong\u003e AEMWE \u003cem\u003ej\u003c/em\u003e-V curves of MoNi\u003csub\u003e4\u003c/sub\u003e || Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4 \u003c/sub\u003eand Pt/C || RuO\u003csub\u003e2\u003c/sub\u003e in alkaline seawater without iR compensation. \u003cstrong\u003ed\u003c/strong\u003e The stability test at 1.0 A cm\u003csup\u003e-2 \u003c/sup\u003efor MoNi\u003csub\u003e4\u003c/sub\u003e || Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4 \u003c/sub\u003ebased AEMWE system in alkaline seawater.\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-6367775/v1/bcbcb9f0cc0a6348997da5ef.png"},{"id":92696829,"identity":"598ae579-2859-44af-946b-f199cba7a222","added_by":"auto","created_at":"2025-10-03 07:09:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4998854,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6367775/v1/68992dad-900f-4480-8ddd-79020d78009f.pdf"},{"id":80516543,"identity":"6eaf3c7d-9bfc-4091-a2fc-f3ccde6fc35e","added_by":"auto","created_at":"2025-04-14 08:11:11","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":23109247,"visible":true,"origin":"","legend":"Iron and oxygen vacancies co-modulated adsorption evolution and lattice oxygen dual-path mechanism for enhanced ampere-level freshwater/seawater oxidation","description":"","filename":"Supporting20250401NatCom.docx","url":"https://assets-eu.researchsquare.com/files/rs-6367775/v1/33da0b8aefbb9941a74702a0.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Iron and oxygen vacancies co-modulated adsorption evolution and lattice oxygen dual-path mechanism for enhanced ampere-level freshwater/seawater oxidation","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAlkaline water electrolysis as an efficient, clean, and environmentally benign technology of hydrogen production, has immense development promises\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. However, the anodic oxygen evolution reaction (OER) goes through slow reaction dynamics because of the complicated four-electron transfer procedure, severely impeding the overall water splitting (OWS) efficiency\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Particularly in the harsh and complex seawater environments, the presence of insoluble impurities and the chloride evolution reaction (ClER) pose significant challenges to the OER kinetics and long-term durability of anode\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. Therefore, designing the high-activity and robust OER catalysts is imperative to achieve the industry-scale freshwater/seawater oxidation.\u003c/p\u003e \u003cp\u003eReported researches have confirmed that the intrinsic OER performance of electrocatalysts possesses strong relevance to the reaction pathway of active sites\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Generally, the main pathways for alkaline OER are classified into two types: adsorbate evolution and lattice oxygen mechanisms (AEM and LOM)\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. For the AEM, the binding strength between the metal sites and oxygenated intermediates (*O, *OH, and *OOH) plays a significant role of catalytic activity, wherein the inherent linear-scaling relationship (ΔG\u003csub\u003eOOH\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;ΔG\u003csub\u003eOH\u003c/sub\u003e + 3.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2 eV) of the binding energies between *OH and *OOH limit the minimal overpotential of 370 mV vs. RHE to accelerate water oxidation\u003csup\u003e\u003cspan additionalcitationids=\"CR8 CR9\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. In sharp contrast, the LOM achieves efficient O\u003csub\u003e2\u003c/sub\u003e release via the direct coupling of *O and oxygen ligand, circumventing the high barrier step of *OOH formation, thus requiring a lower theoretic overpotential\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Nevertheless, the dominant LOM pathway involves repeated refilling/release of lattice oxygen, leading to the unstable structure, and consequently abating the activity and durability of catalysts\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. Undoubtedly, compared with the single OER pathway, dual-path catalysts following the AEM-LOM coupled mechanism can obviate the scaling relationship to achieve high OER activity without diminishing the stability\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. However, developing the dual-path catalysts faces various challenges, as achieving the simultaneous electron transfer process on both metal sites and lattice oxygen within a single component or coordination environment depends on the optimal covalency of metal-oxygen (M-O) bonds\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eNanorod-like nickel molybdate hydrate (NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO), a prospective pre-catalyst, undergoes a complete reconstruction accompanied by co-leaching of crystal water and MoO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e ions under the alkaline OER conditions, resulting in the transformation to γ-NiOOH with the nanocrystal-amorphous feature\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. And the NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO derived γ-NiOOH is considered as an ideal substitute for RuO\u003csub\u003e2\u003c/sub\u003e and IrO\u003csub\u003e2\u003c/sub\u003e benchmarked catalysts due to the satisfactory OER performance\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. Many outstanding works have so far confirmed that the reasonable modify strategies, such as introducing the exogenous heteroatoms or heterostructures\u003csup\u003e\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. can activate the lattice oxygen of NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO catalyst systems for translating the mechanism from AEM to LOM, resulting in the derived NiOOH with preferable OER activity. On the other hand, introducing additional defects is a promising strategy to accelerate the reconfiguration of NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO and reduce the covalency of Ni-O bonds, which can effectively optimize the AEM mechanism of the active phase\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e,\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. Thus, constructing the heteroatoms/oxygen vacancies co-regulated γ-NiOOH may potentially obtain the optimal M-O covalency bonds, further simultaneously activating the metal sites and lattice oxygen.\u003c/p\u003e \u003cp\u003eIn this work, the NiMoO₄\u0026middot;xH₂O serves as the pre-catalyst, while Fe doped Ni\u003csub\u003e2\u003c/sub\u003eP nanoparticles deriving from the Prussian blue analogue (NiFe-PBA) are introduced to optimize the electron configuration of Ni sites in NiMoO\u003csub\u003e4\u003c/sub\u003e, thereby accelerating the deep reconstruction into the Fe atom/oxygen vacancies co-modified γ-NiOOH active phase (O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH) during the electrochemical activation. A series of characterizations, including in-situ \u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003eO isotope-labeling differential electrochemical mass spectrometry (DEMS), in-situ surface-enhanced infrared absorption spectroscopy with attenuated total reflection (ATR-SEIRAS), and chemical probe is employed to confirm the compatible pathway of AEM and LOM in the activated catalyst. Furthermore, the experiment details and density functional theory (DFT) analysis unveil that Fe dopants significantly increases the lattice oxygen activity, while the proper concentration of O\u003csub\u003eV\u003c/sub\u003e regulate the Ni-O covalency bonds and optimize the AEM kinetics. Benefiting from the AEM-LOM coupled mechanism and the excellent mass transfer ability, the reconstructed OER catalyst in alkaline freshwater and seawater delivers 1.0 A cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e current density at 275 and 299 mV, respectively. Moreover, the anion exchange membrane (AEM) water electrolyzer system assembled with Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e and MoNi\u003csub\u003e4\u003c/sub\u003e exhibits preeminent durability in the successive ampere-level seawater electrolysis for 480 h.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eDesign and structural characterizations of pre-catalysts\u003c/h2\u003e \u003cp\u003eNanorod-like Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e arrays, as the pre-catalysts, were directly grown on the nickel foams (NF) via hydrothermal, ion-exchange, and low-temperature phosphating methods as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea and Supplementary Fig.\u0026nbsp;1. The composition and crystal structure of the products during the synthesis process was identified via X-ray diffraction (XRD). In Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb and Supplementary Fig.\u0026nbsp;2, the characteristic peaks ascribing to NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO (PDF#024-7435) constantly persist in the diffraction patterns of NiMoO\u003csub\u003e4\u003c/sub\u003e, PBA@NiMoO\u003csub\u003e4\u003c/sub\u003e, and Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e, indicating that the NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO phase is well-preserved. Significantly, the characteristic peaks of NiFe-PBA (K\u003csub\u003e2\u003c/sub\u003eFeNi(CN)\u003csub\u003e6\u003c/sub\u003e, PDF#023\u0026ndash;0491) completely vanish after the low-temperature phosphating, while the new peaks at 41.1, 43.5, 47.7, and 53.7\u0026deg; that can be indexed to Ni\u003csub\u003e2\u003c/sub\u003eP (PDF#074-1385) in Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e. Due to the absence of angle shift, Fe atoms are present in the Ni\u003csub\u003e2\u003c/sub\u003eP lattice as substitutional dopants, rather than interstitial dopants. The scanning electron microscope (SEM) was manipulated to observe the geometry morphology of samples. The arrays composed of NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO nanorods possessing smooth surface are evenly grown on the NF frame (Supplementary Fig.\u0026nbsp;3). Following ion-exchange process, NiFe-PBA nanocubes cover the surface of nanorods, forming a unique top-hollow structure (Supplementary Fig.\u0026nbsp;4). As depicted in Supplementary Fig.\u0026nbsp;5 and Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec, d, array and top-hollow configuration are retained, while the PBA nanocubes undergo melting and coalesce to form a continuous shell layer encapsulating the nanorods. This morphology is advantageous for accelerating reaction kinetics and enhancing mass transfer. Notably, we found that the dosage of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e and NaH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e2\u003c/sub\u003e\u0026middot;H\u003csub\u003e2\u003c/sub\u003eO has been identified as crucial factors in the synthesis and morphology control of the electrocatalysts (Supplementary Figs.\u0026nbsp;6\u0026ndash;8). Experimental results demonstrate that the absence of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is detrimental to the growth of NiFe PBA on the surface of NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO. Conversely, increasing the amount of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e from 1.2 to 2.4 mmol gives rise to the disappearance of top-hollow configuration in the as-synthesized materials. Similarly, the phosphating process of NiFe-PBA is incomplete when the amount of NaH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e2\u003c/sub\u003e\u0026middot;H\u003csub\u003e2\u003c/sub\u003eO is 0.9 g. However, increasing the dosage of phosphorus source to 2.7 g also results in the loss of the top-hollow structure.\u003c/p\u003e \u003cp\u003eTransmission electron microscopy (TEM) and high-resolution TEM (HRTEM) were employed to investigate the detailed geometric and phase structure of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e composite. In Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ee, the hierarchical nanorod structure composed of PBA derivative and NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO is in good accordance with SEM images. HRTEM image obtained from the exposed interior of the nanorod reveals an interplanar parameter of 0.214 nm, which can be indexed to the (111) facet for Ni\u003csub\u003e2\u003c/sub\u003eP. Above observation aligns with the results of the XRD pattern. We employed the focused ion been (FIB) treatment to expose the cross-section of the Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e composite, and the corresponding TEM and HRTEM images are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ef, Supplementary Figs.\u0026nbsp;9 and 10. The hierarchical configuration, comprising the amorphous layer, Fe-Ni\u003csub\u003e2\u003c/sub\u003eP nanoparticles, and NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO core, can be distinctly visualized. Furthermore, the magnified high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image, corresponds to the region of NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO core (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eg). Two labeled crystal lattices with measured interplanar distances of 0.284 and 0.306 nm are identified, which correspond to the to (02\u0026thinsp;\u0026minus;\u0026thinsp;1) and (20\u0026thinsp;\u0026minus;\u0026thinsp;1) planes of NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO, respectively (Supplementary Fig.\u0026nbsp;11). Based on the angular and lattice spacing relationships intrinsic to the anorthic system, the theoretical angle between the [02\u0026thinsp;\u0026minus;\u0026thinsp;1] and [20\u0026thinsp;\u0026minus;\u0026thinsp;1] crystal orientations is calculated to be 91\u0026deg;, which aligns well with the measurement (as illustrated in the inset of Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eg). The high crystallinity of NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO within the composite is collectively confirmed via above results. Energy-dispersive X-ray spectroscopy (EDS) surface and line scans confirm that exclusively found in the core region is the Mo element, while Fe and P elements are predominantly present on the shell (Supplementary Figs.\u0026nbsp;12 and 13). Notably, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eh-m, the larger mapping area of Ni element (compared to Mo element) in the cross-section of composite, belonging to Fe-Ni\u003csub\u003e2\u003c/sub\u003eP, demonstrates the tight binding between Fe-Ni\u003csub\u003e2\u003c/sub\u003eP and NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO, which is conducive to electron transfer within two phases, thereby optimizing the electron configuration of Ni sites and accelerating the reconstruction process.\u003c/p\u003e \u003cp\u003eTo elucidate the role of each individual component within the composite catalyst system, we synthesized the Fe-doped Ni\u003csub\u003e2\u003c/sub\u003eP (marked as Fe-Ni\u003csub\u003e2\u003c/sub\u003eP) derived from NiFe-PBA on the NF using the same method. The XRD patterns, SEM images, and EDS mapping are presented in Supplementary Figs.\u0026nbsp;14\u0026ndash;16. Then, the electronic structures of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e, Fe-Ni\u003csub\u003e2\u003c/sub\u003eP, and NiMoO\u003csub\u003e4\u003c/sub\u003e were analyzed by X-ray photoelectron spectroscopy (XPS) (Supplementary Fig.\u0026nbsp;17). For the high-resolution Ni 2\u003cem\u003ep\u003c/em\u003e spectrum of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e composite (Supplementary Fig.\u0026nbsp;17b), the deconvoluted peaks at 856.2 and 874.0 eV corresponding to Ni\u003csup\u003e2+\u003c/sup\u003e species exhibits a negative shift in comparison with pure Fe-Ni\u003csub\u003e2\u003c/sub\u003eP and a positive shift compared to pristine NiMoO\u003csub\u003e4\u003c/sub\u003e. The Fe 2\u003cem\u003ep\u003c/em\u003e spectrums in Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e and Fe-Ni\u003csub\u003e2\u003c/sub\u003eP reveal the characteristic signal of Fe\u003csup\u003e2+\u003c/sup\u003e and Fe\u003csup\u003e3+\u003c/sup\u003e. Specifically, the significant positive shift in the bonding energy of the Fe\u003csup\u003e3+\u003c/sup\u003e peaks indicates that the Fe species in Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e composite possess a higher oxidation state in contrast to that of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP. These results reveal that the interaction between Fe-Ni\u003csub\u003e2\u003c/sub\u003eP and NiMoO\u003csub\u003e4\u003c/sub\u003e modulates the electronic structure of Ni in NiMoO\u003csub\u003e4\u003c/sub\u003e, concomitantly enhances the overall oxidation state of Fe sites, thereby increasing the conductivity and accelerating the deep reconfiguration process of pre-catalyst. The depth-profile XPS spectra (Supplementary Fig.\u0026nbsp;18) illustrates that the signal associated with the Ni-P peaks evolves with the increasing of etch level. This observation unveils that Fe-Ni\u003csub\u003e2\u003c/sub\u003eP predominantly concentrated within the interior of the nanorods, which quite agrees with the cross-sectional TEM results.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eElectrochemical activation of active phases\u003c/h3\u003e\n\u003cp\u003eAs presented in Supplementary Figs.\u0026nbsp;19 and 20, the optimization process of current density and potential in the cyclic voltammetry (CV) and chronopotentiometry (CA) measurements, respectively, reveals the dynamic reconstruction and active phases generation of the pre-catalysts for pristine NiMoO\u003csub\u003e4\u003c/sub\u003e and Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e. It is apparent that Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e electrocatalyst possesses faster reconfiguration kinetics with augmented charge transfer capability by reason of the modification of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP species. To explore the dynamic reconstruction of pre-catalysts in OER conditions, in-situ electrochemical and spectroscopy characterizations were employed. Firstly, we used the in-situ electrochemical impedance spectroscopy (in-situ EIS) to study the OER kinetics and electrocatalyst/electrolyte interface. The low-frequency region (10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e \u0026minus;\u0026thinsp;10\u003csup\u003e1\u003c/sup\u003e Hz) of the impedance spectra corresponds to charge transfer between active species and OER intermediates, while the high-frequency region (10\u003csup\u003e1\u003c/sup\u003e \u0026minus;\u0026thinsp;10\u003csup\u003e4\u003c/sup\u003e Hz) reflects electron transfer procedures of the catalyst inner during the electrooxidation reaction\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. As displayed in Supplementary Fig.\u0026nbsp;21 of Bode plots, the phase angle (θ) in the high-frequency region gradually decreases with the increasing applied potentials, wherein the Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e possesses the smallest switched potential at 1.38 V vs. RHE, lower than that of NiMoO\u003csub\u003e4\u003c/sub\u003e (1.41 V vs. RHE) and Fe-Ni\u003csub\u003e2\u003c/sub\u003eP (1.41 V vs. RHE), indicating that the interaction between Fe-Ni\u003csub\u003e2\u003c/sub\u003eP and NiMoO\u003csub\u003e4\u003c/sub\u003e accelerates the generation of active phase. Then, the phase-evolution process of pre-catalysts was identified by in-situ Raman spectra with controlled applied potentials (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea and Supplementary Fig.\u0026nbsp;22). As the progressing of electro-oxidation process, the characteristic bands of Mo-O and Mo\u0026thinsp;=\u0026thinsp;O vibrations at 347, 825, 875, and 950 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e gradually abate and eventually disappear, ascribing to MoO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e leaching under OER conditions. Especially, the typical active specie of γ-NiOOH can be confirmed by the presence of two characteristic peaks at 472 and 552 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e corresponding to E\u003csub\u003eg\u003c/sub\u003e and A\u003csub\u003e1g\u003c/sub\u003e vibration modes for Ni\u003csup\u003e3+\u003c/sup\u003e-O, respectively\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Significantly, the conversion of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e to γ-NiOOH occurs at the lower potential (1.40 V), further demonstrating a faster electrochemical reconstruction.\u003c/p\u003e \u003cp\u003eFollowing the electrochemical activation process, we obtained the reconstructed catalysts (labeled as R-*). We then further analyzed their crystalline, geometric, and electronic structures to elucidate the underlying mechanisms contributing to AEM-LOM dual-path. The XRD pattern of R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e (Supplementary Fig.\u0026nbsp;23) manifests that the characteristic peaks of NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO completely disappear, replaced by two new peaks located at 35.0 and 61.1\u0026deg;, which can be indexed to the (101) and (310) facets of NiOOH (PDF#027\u0026ndash;0956). This transformation is also observed in the XRD pattern of R-NiMoO\u003csub\u003e4\u003c/sub\u003e. Besides, three weak peaks located at 41.1, 47.8, and 54.6\u0026deg; in R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e are attributed to residual Ni\u003csub\u003e2\u003c/sub\u003eP species, which maintain the high conductivity of the whole catalyst. In Ni-(oxy)hydroxides, the ratio for bending and stretching vibration modes intensity (I\u003csub\u003eB\u003c/sub\u003e/I\u003csub\u003eS\u003c/sub\u003e) can function as an indicator of disorder level, in which the lower I\u003csub\u003eB\u003c/sub\u003e/I\u003csub\u003eS\u003c/sub\u003e value represents the higher disorder structure\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e. As profiled in Supplementary Fig.\u0026nbsp;24, the I\u003csub\u003eB\u003c/sub\u003e/I\u003csub\u003eS\u003c/sub\u003e value for R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e is measured at 1.37, contrasting sharply with the 2.16 value found in R-NiMoO\u003csub\u003e4\u003c/sub\u003e, indicating that Fe species from Fe-Ni\u003csub\u003e2\u003c/sub\u003eP migrate into the lattice of restructured NiOOH during electrochemical activation, resulting in a low crystallinity structure.\u003c/p\u003e \u003cp\u003eSEM (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb, c) and TEM (Supplementary Fig.\u0026nbsp;25) images reveal that the 3D morphology of nanorod arrays is preserved in the reconstructed electrocatalyst, but the individual nanorods have evolved into a loose and porous structure. As shown in the HRTEM images (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed, e), the interplanar distance of 0.249 nm corresponds to the (101) facet of γ-NiOOH, aligning to the result of XRD pattern. Notably, discontinuous lattice fringes are present in the materials (the yellow circle highlight in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed), ascribing to the defects via the incorporation of O\u003csub\u003eV\u003c/sub\u003e. The EDS surface and line scans, as presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ef-k and Supplementary Fig.\u0026nbsp;26, demonstrate a uniform distribution of the Fe element throughout the entire nanorod, rather than a concentration in the shell, indicating the introduction of Fe dopants into the whole active phase. Whilst, the marked decrease in the mapping intensity of Mo and P elements, as observed, originates to the leaching of MoO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e and P species under OER conditions. These results confirm that O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH is the real active specie in R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e.\u003c/p\u003e \u003cp\u003eXPS analysis is applied to explore the surface oxidation state changes between pre- and post-catalysts, as well as the differences in the electronic structure environment between reconstructed products. As illustrated in Supplementary Fig.\u0026nbsp;27, the proportion of Ni\u003csup\u003e3+\u003c/sup\u003e and Fe\u003csup\u003e3+\u003c/sup\u003e of R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e exhibits a notable increasing compared to the initial Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e. Meanwhile, the XPS signals related to Mo element and Ni-P bond almost disappear, corresponding to the leaching of MoO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e and the reconstruction of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP during the electrochemical activation. These results are consistent with XRD, Raman spectroscopy, and EDS mapping, further confirming the efficient and deep transformation during activation. It is noteworthy that the proportion of O\u003csub\u003eV\u003c/sub\u003e in the O 1\u003cem\u003es\u003c/em\u003e spectrum slightly increases from 28.08\u0026ndash;30.98% after reconstruction (Supplementary Table\u0026nbsp;1). The electron paramagnetic resonance (EPR) spectra (Supplementary Fig.\u0026nbsp;28a) also provide evidence of the appropriate increase in O\u003csub\u003eV\u003c/sub\u003e, which is conducive to optimizing the AEM kinetics. In Ni 2\u003cem\u003ep\u003c/em\u003e spectrum (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003el), we found that the signal peaks of Ni 2\u003cem\u003ep\u003c/em\u003e\u003csub\u003e3/2\u003c/sub\u003e orbital for R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e center between those of R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP and R-NiMoO\u003csub\u003e4\u003c/sub\u003e, illustrating that Fe dopants and O\u003csub\u003eV\u003c/sub\u003e primarily act as electron acceptors and donors, respectively, and co-modulate the electronic structure of Ni-(oxy)hydroxide. Meanwhile, as presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003em, the peaks of lattice oxygen (M-O) for R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e and R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP significantly shift toward the higher binding energy relative to that of R-NiMoO\u003csub\u003e4\u003c/sub\u003e, unveiling the enhanced Ni-O covalent bands and lattice oxygen activity following the introduction of Fe species\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. Moreover, the slight increasing of O\u003csub\u003eV\u003c/sub\u003e has been also detected in the XPS and EPR spectra of R-NiMoO\u003csub\u003e4\u003c/sub\u003e (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003em and Supplementary Fig.\u0026nbsp;28c), indicating that MoO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e and crystalline water co-leaching is the primary reason for the generation of O\u003csub\u003eV\u003c/sub\u003e in NiMoO\u003csub\u003e4\u003c/sub\u003e system\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. The binding energy of Fe 2\u003cem\u003ep\u003c/em\u003e peak for R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e exhibits a significant negative-shift with respect to that of R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003en) indicates that the over-oxidation of Fe species in active phases has been suppressed, which is favorable to circumvent the Fe leaching thus pacifying lattice oxygen\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. The absence of P and Mo element signals is also observed in Supplementary Fig.\u0026nbsp;29 for XPS spectra of R-Fe-Ni\u003csub\u003e2\u003c/sub\u003eP and R-NiMoO\u003csub\u003e4\u003c/sub\u003e, respectively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eElectrocatalytic OER performance\u003c/h3\u003e\n\u003cp\u003eWe assembled a typical three-electrode system, directly employing the pre-catalysts or benchmarks as the work electrode to test their electrocatalytic performance in O\u003csub\u003e2\u003c/sub\u003e-saturated 1 M KOH. The activated Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e catalyst exhibits the optimal OER performance (as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea), delivering current densities of 10, 100, 500, and 1000 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e at 197, 221, 251, and 275 mV, respectively, which is in excess of other counterparts. Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e exerts the lowest Tafel slope (30.51 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), as described in Supplementary Fig.\u0026nbsp;30, suggesting the superior OER reaction kinetics. Simultaneously, Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e also presents the accelerated charge-transfer capacity, featuring the optimal charge transfer resistance (R\u003csub\u003ect\u003c/sub\u003e) of 0.77 Ω, lower than that of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP (2.91 Ω), NiMoO\u003csub\u003e4\u003c/sub\u003e (1.55 Ω), and RuO\u003csub\u003e2\u003c/sub\u003e (12.61 Ω) in Supplementary Fig.\u0026nbsp;31 and table 2. Moreover, the electrochemical surface area (ECSA) and turnover frequency (TOF) were calculated to assess the intrinsic OER activity (Supplementary Figs.\u0026nbsp;32 and 33). Apparently, Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e displays the maximum ECSA-normalized current density and TOF value. In summary, the systematic comparison of OER activity, Tafel slope, R\u003csub\u003ect\u003c/sub\u003e, C\u003csub\u003edl\u003c/sub\u003e, and TOF is presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb, and the comprehensive OER performance for Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e outperforms that of all control samples. Compared with recently reported OER catalysts (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec), Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e demonstrates the immense prospect for application, especially under ampere-level current densities.\u003c/p\u003e \u003cp\u003eFollowing that, we measured the OER efficiency of catalysts in 1 M KOH\u0026thinsp;+\u0026thinsp;0.5 M NaCl and 1 M KOH\u0026thinsp;+\u0026thinsp;seawater solution. In Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed and e, Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e exhibits low overpotentials of 296 and 299 mV at 1000 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e current density in alkaline artificial and natural seawater, respectively, accompanied by low Tafel slopes (36.14 and 39.64 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). The performance of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e significantly surpasses that of control samples and the state-of-art catalysts (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ef), further demonstrating its underlying application value. Notably, the R\u003csub\u003ect\u003c/sub\u003e of NiMoO\u003csub\u003e4\u003c/sub\u003e discernibly increases from 3.21 to 7.89 Ω when the electrolyte is switched from simulated seawater to real seawater, whereas Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e and Fe-Ni\u003csub\u003e2\u003c/sub\u003eP exhibit slight degradation (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eg and Supplementary Table\u0026nbsp;3 to 4). Meanwhile, as illustrated in the Tafel corrosion plots and derived corrosion data (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eg and Supplementary Table\u0026nbsp;5), Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e possess higher corrosion potential at -0.214 V vs. SCE accompanied by lower current density of 0.124 mA cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e, as compared with Fe-Ni\u003csub\u003e2\u003c/sub\u003eP and initial NiMoO\u003csub\u003e4\u003c/sub\u003e. These results reveal that the negligible decay in natural seawater solution, compared with that in freshwater and simulated seawater, attributes the high intrinsic activity and the presence of amorphous protective layer, which effectively circumvents the ClER and mitigates the impact of impurities.\u003c/p\u003e \u003cp\u003eFe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e shows the satisfactory long-term durability at 1.0 A cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e for 100 h in both alkaline freshwater and seawater (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ei), confirming that the participation of AEM pathway suppresses the damage to stability induced by LOM. Meanwhile, the residual chlorine detection (Supplementary Fig.\u0026nbsp;34) demonstrates that no ClO\u003csup\u003e\u0026minus;\u003c/sup\u003e was generated during the seawater oxidation process. The absence of ClER leads to a commendable Faraday efficiency of 98.26% in alkaline seawater, which is remarkably close to the results obtained in alkaline freshwater (98.45%) (Supplementary Figs.\u0026nbsp;35\u0026ndash;37).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eAEM-LOM dual-path OER mechanism analysis\u003c/h3\u003e\n\u003cp\u003eWe further explore the activation conditions of the dual-path OER mechanism involved in Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e. As profiled in Supplementary Fig.\u0026nbsp;38, the OER activity under different pH values was used to preliminarily determine the pathway of the activated electrocatalysts. Generally, a close association exists between the pH dependence and the proton-reaction order (ρ), with a ρ value closed to 1 manifesting a non-concerted proton-electron transfer pathway\u003csup\u003e\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e\u003c/sup\u003e. Therefore, Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e, NiMoO\u003csub\u003e4\u003c/sub\u003e, and Fe-Ni\u003csub\u003e2\u003c/sub\u003eP catalysts may undergo the LOM pathway (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea). Notably, the strongest pH-dependence of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e at 1.55 V vs. RHE suggests that it possesses the higher lattice oxygen activity at a lower potential. Furthermore, O\u003csub\u003e2\u003c/sub\u003e signal released by the \u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003eO isotope-labeled Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e during OER process in H\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e16\u003c/sup\u003eO was captured via in-situ DEMS to analyze the OER mechanism. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb, mass spectrometer detected distinct signals of \u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003eO\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003eO and \u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003eO\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003eO gas, corresponding to the O\u003csub\u003e2\u003c/sub\u003e products from AEM and LOM pathway, respectively\u003csup\u003e\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e\u003c/sup\u003e. Meanwhile, the absence of significant \u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003eO\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003eO signal suggests that only one lattice oxygen participates in the reaction. In addition, in-situ ATR-SEIRAS was manipulated to detect the interplay between oxygen-containing intermediates and the catalytic surface during OER process. In Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ec, two distinct peaks are observed in the range from 1000 to 1200 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, which emerged with the increasing of applied potentials. The one centered at 1052 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e can be indexed to the *OOH intermediate generated from AEM pathway, while the vibration of O-O in the characteristic intermediate from LOM can be discovered at 1211 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, synthetically demonstrating the compatible mechanism of both AEM and LOM in Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e57,58\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eTo distinguish in detail the contributions of each component in the Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e composite to OER mechanism, chemical probes were employed to detect the forms and chemical properties of oxygenated intermediates on the catalyst surface. Methanol is known to compete for *OH intermediate adsorption on the catalyst surface under electrooxidation conditions. Consequently, methanol oxidation reaction (MOR) serves as a diagnostic measurement to evaluate *OH adsorption behavior, with MOR current density exhibiting a direct positive correlation with *OH surface coverage\u003csup\u003e\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e\u003c/sup\u003e. As depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ed, Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e and NiMoO\u003csub\u003e4\u003c/sub\u003e exhibit significantly higher MOR current densities than Fe-Ni\u003csub\u003e2\u003c/sub\u003eP at equivalent potentials, indicating more efficient and unimpeded *OH adsorption due to the introduction of O\u003csub\u003eV\u003c/sub\u003e. Furthermore, the moderate enhancement of MOR current densities relative to the OER activity in Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e suggests that Fe species and O\u003csub\u003eV\u003c/sub\u003e in the active phase jointly optimize the *OH adsorption energy and deprotonation kinetics in the AEM pathway. Similarly, tetramethylammonium cation (TMA\u003csup\u003e+\u003c/sup\u003e) competitively adsorbs the characteristic intermediate (peroxide, O\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e) in the LOM pathway due to the strong electrostatic interaction, hindering the OER process dominated by LOM\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. The negligible decrease of OER performance for NiMoO\u003csub\u003e4\u003c/sub\u003e in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ee, suggests that R-NiMoO\u003csub\u003e4\u003c/sub\u003e primarily follows the AEM pathway. Conversely, Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e and Fe-Ni\u003csub\u003e2\u003c/sub\u003eP exhibit marked deterioration in OER activity and kinetics, indicating that Fe doping induces the activation of oxygen ligands in active phases.\u003c/p\u003e \u003cp\u003eDFT calculation was employed to obtain deeper understanding of the electron configuration and OER mechanism. We constructed the theoretical structure models of the real active species for NiOOH, Ni(Fe)OOH, and O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH (Supplementary Fig.\u0026nbsp;39). Based on the analysis for density of states (DOS), the Ni 3\u003cem\u003ed\u003c/em\u003e band center in O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH (-2.921 eV) shifts upward toward the Fermi level (E\u003csub\u003eF\u003c/sub\u003e) with respect to Ni(Fe)OOH (-2.993 eV) and NiOOH (-3.043 eV) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ef). This result indicates the Ni sites in O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH is more conductive to donate electrons, beneficial for increasing the proportion of AEM pathway in OER procedures. Additionally, the higher orbital overlap of Ni 3\u003cem\u003ed\u003c/em\u003e and O 2\u003cem\u003ep\u003c/em\u003e above E\u003csub\u003eF\u003c/sub\u003e suggests a stronger interaction between metal sites and oxygen ligands. Apparently, the rank of DOS overlap degree is Ni(Fe)OOH \u0026gt; O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH \u0026gt; NiOOH (as depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ef). This observation, consistent with the XPS spectra results (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003el, m), implies the moderate Ni-O covalency for O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH under the co-modulation of Fe species and O\u003csub\u003eV\u003c/sub\u003e, providing the prerequisite for triggering AEM-LOM dual-path.\u003c/p\u003e \u003cp\u003eThe Gibbs free energy was computed to demonstrated the optimal active sites for AEM and LOM in O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH (Supplementary Figs.\u0026nbsp;40\u0026ndash;42). As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eg, the deprotonation process (*OH \u0026rarr; *O) on both Ni and Fe sites is identified as rate-determining step (RDS), wherein the energy barrier on Ni site is optimized to 2.20 eV. Considering the strong redox activity of Ni sites in O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH, Ni atoms may preferentially adsorb the OH\u003csup\u003e\u0026minus;\u003c/sup\u003e, further coupling with oxygen ligands in matrix after deprotonation, which follows the single-metal-site mechanism (SMSM), rather than the oxygen-vacancy-site mechanism (OVSM) (Supplementary Fig.\u0026nbsp;43). Consequently, we simulated the energy barriers of the LOM pathway under OVSM and SMSM. As presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eh, the RDS of O site exhibits the optimal Gibbs free energy difference (ΔG) of 1.98 eV, indicating that O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH follows the OVSM. Furthermore, comparing the theoretical overpotentials of AEM (0.97 V) and LOM (0.75 V) reveals the AEM is inclined to occur at higher potentials. This is advantageous for circumventing the structural collapse induced by the LOM pathway at high current densities, thereby obtaining the promising OER catalyst together with activity and stability.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eFreshwater/seawater splitting performance\u003c/h3\u003e\n\u003cp\u003eGiven the remarkable efficiency and durability of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e for electrocatalytic freshwater/seawater oxidation, the activated Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e electrode was employed as the anode, while the as-prepared MoNi\u003csub\u003e4\u003c/sub\u003e HER catalyst served as cathode, to construct an OWS electrolyzer for evaluating the application potential at industrial conditions. The MoNi\u003csub\u003e4\u003c/sub\u003e || Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e electrode-pair can reduce the cell voltages to 1.784 and 1.798 V in alkaline freshwater and seawater (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea), respectively, which competent to drive a current density of 1.0 A cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e at room temperature. It is noted that the OWS performance of MoNi\u003csub\u003e4\u003c/sub\u003e || Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e surpasses that of benchmarked electrocatalysts pair (Pt/C || RuO\u003csub\u003e2\u003c/sub\u003e), which requires 2.299 V (alkaline freshwater) and 2.413 V (alkaline seawater). Furthermore, after 100 h of continuous freshwater/seawater splitting at ampere-scale constant current density, the MoNi\u003csub\u003e4\u003c/sub\u003e || Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e system exhibits slight performance degradation, underscoring its excellent durability. Moreover, as shown in Supplementary Fig.\u0026nbsp;44, a piece of solar cell sheet can drive OWS in the MoNi\u003csub\u003e4\u003c/sub\u003e || Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e system, featuring continuous bubble release of hydrogen and oxygen on the catalytic surface. This result validates the application potential of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e in the renewable energy conversion.\u003c/p\u003e \u003cp\u003eThe anion exchange membrane (AEM) natural seawater electrolyzer using Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e and MoNi\u003csub\u003e4\u003c/sub\u003e electrocatalyst as anode and cathode, respectively, was assembled to simulate the electrocatalytic hydrogen production process in the industrial application. The geometric area of both anode and cathode was 1 \u0026times; 1 cm\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e, while the exchange membrane was tailored to 3 \u0026times; 3 cm\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. As illustrated in the \u003cem\u003ej\u003c/em\u003e-V curves (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ec), MoNi\u003csub\u003e4\u003c/sub\u003e || Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e electrolyzer exhibits superior AEM alkaline seawater splitting activity at 25\u0026deg;C, achieving 2.616 V cell voltage to reach 1.0 A cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e, which surpasses that of benchmarked Pt/C || RuO\u003csub\u003e2\u003c/sub\u003e pair (3.322 V at 1.0 A cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e). Notably, the MoNi\u003csub\u003e4\u003c/sub\u003e || Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e AEM system maintained steady seawater electrolysis for 480 h at ampere-level current density (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ed), highlighting its long-term durability for industrial application.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eTo sum up, we designed Fe-Ni\u003csub\u003e2\u003c/sub\u003eP decorated NiMoO\u003csub\u003e4\u003c/sub\u003e hydrate (Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e) as a pre-catalyst with optimized electron configuration, thereby expediting the deep reconfiguration into O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH active phase. XPS analysis reveals that the Fe species and O\u003csub\u003eV\u003c/sub\u003e synergistically regulate the electronic structure of NiOOH, providing proper covalency of Ni-O bonds for simultaneously triggering metal sites and oxygen ligands. In-situ \u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003eO isotope-labeling DEMS, in-situ ATR-SEIRAS, chemical probe experiments and DFT calculations confirm the AEM-LOM dual-path OER mechanism with optimized intermediates adsorption energy for O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH. Consequently, the activated Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e catalyst demonstrates commendable OER activity. It features 275 and 299 mV overpotentials to drive the ampere-level freshwater and seawater oxidation, respectively, with the negligible activity decay for 100 h of continuous electrocatalysis in tree-electrode cell. Furthermore, as-prepared Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e electrode, when employed as the anode in an AEMWE system, achieving continuous ampere-level seawater electrolysis for 480 h at 1.0 A cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eMaterials\u003c/h2\u003e \u003cp\u003eNickel nitrate hexahydrate (Ni(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e\u0026middot;6H\u003csub\u003e2\u003c/sub\u003eO), potassium ferricyanide (K\u003csub\u003e3\u003c/sub\u003eFe(CN)\u003csub\u003e6\u003c/sub\u003e), trisodium citrate (C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e), sodium hypophosphite (NaH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e2\u003c/sub\u003e\u0026middot;H\u003csub\u003e2\u003c/sub\u003eO), ammonium molybdate tetrahydrate ((NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eMo\u003csub\u003e7\u003c/sub\u003eO\u003csub\u003e24\u003c/sub\u003e), ruthenium dioxide (RuO\u003csub\u003e2\u003c/sub\u003e), carbon-supported platinum (Pt/C, 20 wt.%), potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAOH) were sourced from Aladdin. Absolute ethanol, acetone, isopropanol, and hydrochloric acid were sourced from Zhisheng. All chemical reagents employed in this study were of purity exceeding analytical grade and utilized directly without undergoing any additional purification procedures. In the process of solution formulation, deionized (DI) water was exclusively used as the solvent to ensure consistent experimental conditions. We collected natural seawater from the Bohai sea in Hebei Province, China, and used after filtering.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003ePreparation of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e\u003c/h2\u003e \u003cp\u003eNikel foam (NF) was tailored to 3 \u0026times; 4 cm\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e and rinsed by ultrasonication in acetone, diluted hydrochloric acid, absolute ethanol, and DI water, to eliminate the oils and oxides. To synthesis nickel molybdate hydrate (NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO), Ni(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e\u0026middot;6H\u003csub\u003e2\u003c/sub\u003eO and (NH\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e6\u003c/sub\u003eMo\u003csub\u003e7\u003c/sub\u003eO\u003csub\u003e24\u003c/sub\u003e (molar ratio 4:1) with 60 mL of DI water were poured into the 100 mL Teflon-lined receptacle, and a homogeneous solution was obtained after continuous stirring for at least 15 min. Then, the receptacle was sealed into a stainless-steel autoclave and kept at 150\u0026deg;C for 6 h. Once cooled to room temperature, the product was repeatedly rinsed with DI water and absolute ethanol three times and dried in a vacuum oven at 60\u0026deg;C for 12 h. Then, the as-prepared NiMoO\u003csub\u003e4\u003c/sub\u003e\u0026middot;xH\u003csub\u003e2\u003c/sub\u003eO was immersed in the 40 mL aqueous solution hybrid containing 20 mL solution A (0.8 mmol Ni(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e\u0026middot;6H\u003csub\u003e2\u003c/sub\u003eO and a certain dosage of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e) and 20 mL solution B (0.5 mmol K\u003csub\u003e3\u003c/sub\u003eFe(CN)\u003csub\u003e6\u003c/sub\u003e) for 26 h at room temperature to obtain PBA@NiMoO\u003csub\u003e4\u003c/sub\u003e. Finally, a certain amount of NaH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e2\u003c/sub\u003e\u0026middot;H\u003csub\u003e2\u003c/sub\u003eO was accurately weighed and put in an alumina ceramic container together with PBA@NiMoO\u003csub\u003e4\u003c/sub\u003e. Placing the container in the central position of the quartz tube, wherein PBA@NiMoO\u003csub\u003e4\u003c/sub\u003e located at the downstream of argon flow. We obtained the Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e after two-hour low-temperature phosphorization process at 300\u0026deg;C.\u003c/p\u003e \u003cp\u003eThe preparation methods for counterparts and benchmarked catalysts can be found in the Supplementary Text.\u003c/p\u003e \u003c/div\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the main manuscript or the supplementary materials, all employed data are available.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors acknowledge the financial support from the National Natural Science Foundation of China (Grant No. 21371149, 21671168) and the financial support from the Natural Science Foundation of Hebei Province (Grant No. B2021203016, 22281403Z), S\u0026amp;T Program of Hebei (236Z4405G) and Hebei Youth Top-notch Talent Support Program. The authors thank the subsidy for Hebei Key Laboratory of Applied Chemistry after Operation Performance (22567616H).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eX.W. conducted most experiments and data analysis. X.Y. and J.J. helped with HAADF-STEM and TEM measurements. H.N. assisted in electrochemical measurements. L.H. and F.M. oversaw the project and assisted in data analysis. The final version of the text has been carefully reviewed and approved by all authors for submission.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors report no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eHuang W et al (2022) Ligand modulation of active sites to promote electrocatalytic oxygen evolution. Adv Mater 34:2200270\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCai Z et al (2022) Reinforced layered double hydroxide oxygen-evolution electrocatalysts: a polyoxometallic acid wet‐etching approach and synergistic mechanism. Adv Mater 34:2110696\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang T et al (2018) NiFe (Oxy) hydroxides derived from NiFe disulfides as an efficient oxygen evolution catalyst for rechargeable Zn-air batteries: the effect of surface S residues. Adv Mater 30:1800757\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen L et al (2024) Seawater electrolysis for fuels and chemicals production: fundamentals, achievements, and perspectives. Chem Soc Rev 53:7455\u0026ndash;7488\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang A et al (2023) Enhancing oxygen evolution reaction by simultaneously triggering metal and lattice oxygen redox pair in iridium loading on Ni-doped Co\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e. Adv Energy Mater 13:2302537\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDionigi F et al (2020) In-situ structure and catalytic mechanism of NiFe and CoFe layered double hydroxides during oxygen evolution. Nat Commun 11:2522\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\u003eHuang Z et al (2021) Tuning of lattice oxygen reactivity and scaling relation to construct better oxygen evolution electrocatalyst. Nat Commun 12:3992\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXie X et al (2022) Oxygen evolution reaction in alkaline environment: material challenges and solutions. Adv Funct Mater 32:2110036\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang G et al (2024) Selective activation of lattice oxygen site through coordination engineering to boost the activity and stability of oxygen evolution reaction. Angew Chem Int Ed 63:e202407509\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLin C et al (2021) In-situ reconstructed Ru atom array on α-MnO\u003csub\u003e2\u003c/sub\u003e with enhanced performance for acidic water oxidation. Nat Catal 4:1012\u0026ndash;1023\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang Z, Goddard III, W. A., Xiao H (2023) Potential-dependent transition of reaction mechanisms for oxygen evolution on layered double hydroxides. Nat Commun 14:4228\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXin S et al (2023) Coupling adsorbed evolution and lattice oxygen mechanism in Fe-Co(OH)\u003csub\u003e2\u003c/sub\u003e/Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e heterostructure for enhanced electrochemical water oxidation. Adv Funct Mater 33:2305243\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu X et al (2020) Complete reconstruction of hydrate pre-catalysts for ultrastable water electrolysis in industrial-concentration alkali media. Cell Rep Phys Sci 1:100241\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eD\u0026uuml;rr RN et al (2021) From NiMoO\u003csub\u003e4\u003c/sub\u003e to γ-NiOOH: detecting the active catalyst phase by time resolved in situ and operando Raman spectroscopy. ACS Nano 15:13504\u0026ndash;13515\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi J et al (2018) Low-crystalline bimetallic metal-organic framework electrocatalysts with rich active sites for oxygen evolution. ACS Energy Lett 4:285\u0026ndash;292\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang Y, Wang Z, Xiao H, Liu Q, Wang X (2024) Activating and stabilizing lattice oxygen via self-adaptive Zn-NiOOH sub-nanowires for oxygen evolution reaction. J Am Chem Soc 146:29006\u0026ndash;29016\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang Y et al (2024) Activating lattice oxygen based on energy band engineering in oxides for industrial water/saline oxidation. Energy Environ Sci 17:3347\u0026ndash;3357\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFan W et al (2024) Biomimetic Stylophora pistillata-like NiMoO\u003csub\u003e4\u003c/sub\u003e/NiFeS crystalline-amorphous phase boundary activated lattice oxygen mechanism for efficient electrochemical water oxidation. Chem Eng J 502:158106\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhu J, Qian J, Peng X, Xia B, Gao D (2023) Etching-induced surface reconstruction of NiMoO\u003csub\u003e4\u003c/sub\u003e for oxygen evolution reaction. Nano-Micro Lett 15:30\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJiang R et al (2024) Redox promoted rapid and deep reconstruction of defect-rich nickel precatalysts for efficient water oxidation. Small 20:2401384\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLyons ME, Doyle RL, Brandon MP (2011) Redox switching and oxygen evolution at oxidized metal and metal oxide electrodes: iron in base. Phys Chem Chem Phys 13:21530\u0026ndash;21551\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhu K, Zhu X, Yang W (2019) Application of in situ techniques for the characterization of NiFe-based oxygen evolution reaction (OER) electrocatalysts. Angew Chem Int Ed 58:1252\u0026ndash;1265\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang J et al (2019) Identification of key reversible intermediates in self-reconstructed nickel‐based hybrid electrocatalysts for oxygen evolution. Angew Chem Int Ed 131:17619\u0026ndash;17625\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYe P et al (2024) Lattice oxygen activation and local electric field enhancement by co-doping Fe and F in CoO nanoneedle arrays for industrial electrocatalytic water oxidation. Nat Commun 15:1012\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang H et al (2024) Application progress of NiMoO\u003csub\u003e4\u003c/sub\u003e electrocatalyst in basic oxygen evolution reaction. Catal Sci Technol 14:533\u0026ndash;554\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuan Xu H et al (2025) Oxygen plasma triggered Co-O-Fe motif in Prussian blue analogue for efficient and robust alkaline water oxidation. Angew Chem Int Ed 64:e202415423\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXu Z et al (2022) Metal-organic framework-derived 2D NiCoP nanoflakes from layered double hydroxide nanosheets for efficient electrocatalytic water splitting at high current densities. ACS Sustain Chem Eng 10:11577\u0026ndash;11586\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang X et al (2022) In situ reconstructed Zn doped Fe\u003csub\u003ex\u003c/sub\u003eNi\u003csub\u003e(1\u0026ndash;x)\u003c/sub\u003eOOH catalyst for efficient and ultrastable oxygen evolution reaction at high current densities. Small 18:2203710\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu S, Ren S, Gao R, Liu X, Wang L (2022) Atomically embedded Ag on transition metal hydroxides triggers the lattice oxygen towards sustained seawater electrolysis. Nano Energy 98:107212\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuo L et al (2023) Dual-doping NiMoO\u003csub\u003e4\u003c/sub\u003e with multi-channel structure enable urea-assisted energy-saving H\u003csub\u003e2\u003c/sub\u003e production at large current density in alkaline seawater. Appl Catal B-Environ 320:121977\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSong Y et al (2023) Alleviating the work function of vein-like Co\u003csub\u003eX\u003c/sub\u003eP by Cr doping for enhanced seawater electrolysis. Adv Funct Mater 33:2214081\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhou L, Huang Z, Kang F, Lv R (2023) Bimetallic substrate induction synthesis of binder-free electrocatalysts for stable seawater oxidation at industrial current densities. Chem Eng J 458:141457\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLv X et al (2023) Atomic-level surface engineering of nickel phosphide nanoarrays for efficient electrocatalytic water splitting at large current density. Adv Funct Mater 33:2205161\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang Y et al (2024) Stable tetravalent Ni species generated by reconstruction of FeB-wrapped NiMoO pre-catalysts enable efficient water oxidation at large current densities. Appl Catal B-Environ 341:123297\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYao Y et al (2024) Enhancing the stability of NiFe-layered double hydroxide nanosheet array for alkaline seawater oxidation by Ce doping. J Energy Chem 91:306\u0026ndash;312\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYu Q et al (2024) MXene-mediated reconfiguration induces robust nickel-iron catalysts for industrial-grade water oxidation. P Natl Sci 121:e1975073175\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen Y et al (2024) Boosting oxygen evolution reaction by FeNi hydroxide-organic framework electrocatalyst toward alkaline water electrolyzer. Nat Commun 15:7278\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLuo X et al (2024) Fe-S dually modulated adsorbate evolution and lattice oxygen compatible mechanism for water oxidation. Nat Commun 15:8293\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYou H et al (2022) Monolayer NiIr-layered double hydroxide as a long-lived efficient oxygen evolution catalyst for seawater splitting. J Am Chem Soc 144:9254\u0026ndash;9263\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLuo X et al (2022) Spherical Ni\u003csub\u003e3\u003c/sub\u003eS\u003csub\u003e2\u003c/sub\u003e/Fe-NiP\u003csub\u003ex\u003c/sub\u003e magic cube with ultrahigh water/seawater oxidation efficiency. Adv Sci 9:2104846\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXu X et al (2023) Fe-doped and carbon composite multiphase hetero-structured catalysts based on the ion-exchange strategy for seawater electrolysis. ACS Sustain Chem Eng 11:15338\u0026ndash;15349\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi M et al (2023) Synergetic regulation of CeO\u003csub\u003e2\u003c/sub\u003e modification and (W\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e)\u003csup\u003e2\u0026ndash;\u003c/sup\u003e intercalation on NiFe-LDH for high-performance large-current seawater electrooxidation. Appl Catal B-Environ 330:122612\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu D et al (2023) Fe-regulated amorphous‐crystal Ni(Fe)P\u003csub\u003e2\u003c/sub\u003e nanosheets coupled with Ru powerfully drive seawater splitting at large current density. Small 19:2300030\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMalek A, Xue Y, Lu X (2023) Dynamically restructuring Ni\u003csub\u003ex\u003c/sub\u003eCr\u003csub\u003ey\u003c/sub\u003eO electrocatalyst for stable oxygen evolution reaction in real seawater. Angew Chem Int Ed 135:e202309854\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAndaveh R et al (2023) Boosting the electrocatalytic activity of NiSe by introducing MnCo as an efficient heterostructured electrocatalyst for large-current-density alkaline seawater splitting. Appl Catal B-Environ 325:122355\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi Z et al (2024) Carbon oxyanion self-transformation on NiFe oxalates enables long‐term ampere‐level current density seawater oxidation. Angew Chem Int Ed 63:e202316522\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKang X et al (2023) A corrosion-resistant RuMoNi catalyst for efficient and long-lasting seawater oxidation and anion exchange membrane electrolyzer. Nat Commun 14:3607\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang H et al (2023) Dense crystalline/amorphous phosphides/oxides interfacial sites for enhanced industrial-level large current density seawater oxidation. ACS Nano 17:16008\u0026ndash;16019\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYu W et al (2024) Unique CoP microflower decorated with phosphorous-enriched PtP\u003csub\u003e2\u003c/sub\u003e onto nickel foam with interfacial electronic interactions to boost alkaline water‐splitting. Adv Funct Mater 34:2313935\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHe L et al (2024) Three-dimensional porous NiCoP foam enabled high-performance overall seawater splitting at high current density. J Mater Chem A 12:2680\u0026ndash;2684\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShen X et al (2024) Construction of heterojunction-rich metal nitrides porous nanosheets electrocatalyst for alkaline water/seawater splitting at large current density. Small 20:2310535\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi J et al (2024) Highly anti-corrosive NiFe LDHs-NiFe alloy hybrid enables long-term stable alkaline seawater electrolysis. Rare Met 43:4321\u0026ndash;4332\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuo L et al (2024) Phosphorus defect mediated electron redistribution to boost anion exchange membrane-based alkaline seawater electrolysis. Adv Energy Mater 14:2400975\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMefford JT et al (2016) Water electrolysis on La\u003csub\u003e1\u0026thinsp;\u0026ndash; x\u003c/sub\u003e Sr\u003csub\u003ex\u003c/sub\u003eCoO\u003csub\u003e3\u0026ndash;δ\u003c/sub\u003e perovskite electrocatalysts. Nat Commun 7:11053\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu L et al (2024) Antagonism effect of residual S triggers the dual-path mechanism for water oxidation. J Energy Chem 93:568\u0026ndash;579\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSivasankar N, Weare WW, Frei H (2011) Direct observation of a hydroperoxide surface intermediate upon visible light-driven water oxidation at an Ir oxide nanocluster catalyst by rapid-scan FT-IR spectroscopy. J Am Chem Soc 133:12976\u0026ndash;12979\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHao Y et al (2023) Switching the oxygen evolution mechanism on atomically dispersed Ru for enhanced acidic reaction kinetics. J Am Chem Soc 145:23659\u0026ndash;23669\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMei Y et al (2022) High-entropy alloy with Mo-coordination as efficient electrocatalyst for oxygen evolution reaction. ACS Catal 12:10808\u0026ndash;10817\u003c/span\u003e\u003c/li\u003e\u003c/ol\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":"nickel molybdate hydrate, reconstruction, dual-path mechanism, oxygen evolution reaction, seawater electrolysis","lastPublishedDoi":"10.21203/rs.3.rs-6367775/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6367775/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eConjointly activating metal and lattice oxygen sites to trigger the adsorbate evolution and lattice oxygen mechanisms coupled path holds promise for balancing activity and stability in oxygen evolution reaction (OER) catalysts, yet confronting significant challenges. Herein, we develop Fe species and oxygen vacancies co-regulated Ni-(oxy)hydroxide (O\u003csub\u003eV\u003c/sub\u003e-Ni(Fe)OOH), derived from deep reconstruction of Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e pre-catalyst during OER, which realizes the AEM-LOM dual-path mechanism with optimal metal-oxygen covalent bonds, as confirmed via in-situ mass/spectroscopy spectrometry and chemical probes. Experimental details and theoretical calculation analysis reveals the enhanced AEM kinetics on the Ni site via the co-regulation of Fe species and O\u003csub\u003eV\u003c/sub\u003e, featuring upshifted Ni 3\u003cem\u003ed\u003c/em\u003e band centers, while the Fe incorporation activates the O site with preferable adsorption free energy for LOM intermediates. Benefiting from the AEM-LOM dual-path mechanism, the activated Fe-Ni\u003csub\u003e2\u003c/sub\u003eP/NiMoO\u003csub\u003e4\u003c/sub\u003e catalyst affords an ampere-scale current density of 1.0 A cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e at low overpotentials of 275 and 299 mV in 1 M KOH and 1 M KOH\u0026thinsp;+\u0026thinsp;seawater, respectively, and maintains seawater electrocatalysis for 480 h in the anion exchange membrane water electrolysis (AEMWE) cell. This work demonstrates a strategy to trigger the dual-path OER mechanism for efficient and stable electrocatalytic water splitting under harsh conditions.\u003c/p\u003e","manuscriptTitle":"Iron and oxygen vacancies co-modulated adsorption evolution and lattice oxygen dual-path mechanism for enhanced ampere-level freshwater/seawater oxidation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-14 08:03:06","doi":"10.21203/rs.3.rs-6367775/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":"c50bbd5d-807c-4aee-9bc5-b16575f8f03b","owner":[],"postedDate":"April 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":47002825,"name":"Physical sciences/Chemistry/Catalysis/Electrocatalysis"},{"id":47002826,"name":"Physical sciences/Materials science/Nanoscale materials/Electronic properties and materials"}],"tags":[],"updatedAt":"2025-10-03T07:08:59+00:00","versionOfRecord":{"articleIdentity":"rs-6367775","link":"https://doi.org/10.1038/s41467-025-63844-x","journal":{"identity":"nature-communications","isVorOnly":false,"title":"Nature Communications"},"publishedOn":"2025-10-02 04:00:00","publishedOnDateReadable":"October 2nd, 2025"},"versionCreatedAt":"2025-04-14 08:03:06","video":"","vorDoi":"10.1038/s41467-025-63844-x","vorDoiUrl":"https://doi.org/10.1038/s41467-025-63844-x","workflowStages":[]},"version":"v1","identity":"rs-6367775","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6367775","identity":"rs-6367775","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}