Synthesis and structure of FcNiOF precursorFcNiOF nanosheets grown on conductive Ni foam were synthesized using a facile hydrothermal method that is scalable toward industrial implementation (Fig. 1A). The color of Ni foam turns dark yellow, indicating the growth of FcNiOF nanosheets on the surface. The scanning electron microscopy (SEM) shows the uniform coverage of nanosheets standing densely on Ni foam substrate (Fig. 1B), constituting a vertical array structure (Fig. 1C). Such a unique array architecture endows with high porosity and large surface area favorable for dynamic transport of reactants and gaseous products, especially critical in drastic catalysis at high current densities. The transmission electron microscopy (TEM) reveals that these unit nanosheets have thin leaf-like structures and smooth surfaces, with an average thickness of around 28.9 nm (Supplementary Fig. 1) and several hundred nanometers in radial scale (Fig. 1D). The X-ray diffraction (XRD) of FcNiOF in Fig. 1E shows that all diffraction peaks except an accidental peak at 11.4° that can be related to the structure of carboxyl rings (PDF no. 50-2093) correspond to the simulated patterns basing on FcZn-MOF structure (CCDC no. 716347)38. So, a crystal structure is determined that each Ni atom is coordinated by six O atoms of two carboxylate groups on different Fc units, and all the Fc units linked to each other with Ni atoms to form 2D lamella (Fig. 1A and Supplementary Fig. 2). However, the internal crystalline textures in these nanosheets are barely discernable under high-resolution TEM (HRTEM, Supplementary Fig. 3), similar to most observations of MOF texture36,39. The energy-dispersive X-ray spectroscopy (EDS) analysis reveals the composition of Fe, Ni, C, and O elements in FcNiOF (Supplementary Fig. 4), and the corresponding elemental mapping visualizes their uniform distributions in an individual sheet (Fig. 1F).Fig. 1: Structural characterizations of FcNiOF.A Synthetic process of FcNiOF, (B, C) SEM images at different scale bars, (D) TEM image, (E) XRD pattern, and (F) EDS elemental maps of FcNiOF.To probe the chemical composition and coordination, the Fourier-transform infrared (FT-IR), Raman and X-ray photoelectron spectroscopy spectra were further carried out on the as-synthesized FcNiOF nanosheets. In Supplementary Fig. 5, the FT-IR band located at 1670 cm−1 that belongs to the C = O stretching vibration in the Fc-carboxyl groups vanishes completely in FcNiOF, which indicates that Ni atoms are successfully conjugated on the carboxyl groups of Fc units35. The Raman bands at 605 and 345 cm−1 are assigned to the characteristic ring-internal vibration mode and ring-external vibration mode of Fc units, respectively (Supplementary Fig. 6). The other bands assignments in the FT-IR and Raman spectra are listed in Supplementary Tables 1 and 2, respectively. The XPS survey analysis in Supplementary Fig. 7 indicates that FcNiOF contains four elements, Ni, Fe, C, and O, consistent with the EDS result. Moreover, two spin-orbit peaks located at 855.5 (Ni 2p3/2) and 873.1 eV (Ni 2p1/2) in high-resolution Ni-2p spectrum can be attributed to the Ni2+ ions coordinated with O atoms in carboxylic groups, besides the concomitant satellite peaks; the two spin-orbit peaks at 707.7 (Fe 2p3/2) and 720.5 eV (Fe 2p1/2) in high-resolution Fe-2p spectrum can be associated with Fe2+ ions in Fc units. The presence of carboxylic linkers is further verified by the XPS spectra of C-1s and O-1s cores.Active species generation via CV activationThe cyclic voltammetry (CV) activation was first conducted to derive highly active and stable redox species adapted to large current densities. Interestingly, the CV curves show the gradual increase in the closed areas with scan cycles, reaching the steady maximum at the 10th cycle (Fig. 2A). The corresponding growth of metal Ni/Fe redox peaks indicates the increased pseudocapacitance by proliferous active sites, which implies the dynamic reconstruction occurring. By estimated from reverse scans, the overpotential at 0.2 A/cm2 gradually decreases from 284 mV at the initial scan to 252 mV upon stabilization after 10 cycles (Supplementary Fig. 8), indicating a fast and effective OER activation. In situ electrochemical impedance spectroscopy (EIS) manifests that the charge transport resistance (\({{{\rm{R}}}}_{{{\rm{ct}}}}\)) gradually decreases from 11.02 to 1.57 ohm (Ω) as the CV proceeds (Fig. 2B), which reveals more favorable charge transfer after CV activation. The noticeable evolution of electrochemical properties induced by 10-cycle CV scans suggests a self-optimized reconstruction toward highly reactive species.Fig. 2: Active-species generation during CV activation.A CV curves of FcNiOF measured at 50 mV s−1. Note: the geometric surface area (\({{\rm{GSA}}}\)) is 0.25 cm2; series resistance (\({{{\rm{R}}}}_{{{\rm{s}}}}\)) is 2.1 Ω. B In situ EIS spectra with equivalent circuit model of FcNiOF at 1.524 VRHE. C TEM and HRTEM images of FeNiHOF. D Raman spectra and XPS spectra of (E) Ni 2p and (F) Fe 2p cores, for FcNiOF and FeNiHOF. G Schematic diagram of reconstruction process from FcNiOF to FeNiHOF.Further, systematic structural characterizations were conducted to disclose the reconstructed active species after CV activation. From the SEM images (Supplementary Fig. 9), the morphology of vertical nanosheet arrays remains unchanged, which is critical for ensuring mechanical adhesion and specific surface area for high-current-density catalysis. The TEM images of nanosheets display that their surfaces appear rough and uneven (Supplementary Fig. 10), distinguishable from the original smooth appearance. The HRTEM image (Fig. 2C) recognizes the emergence of some local small crystal domains, and their lattice fringes can be assigned to the (012) and (015) planes of Fe-Ni layered double hydroxides (FeNiLDH), respectively, corresponding to the periodic atom strength and SAED patterns (Supplementary Fig. 11). The XRD patterns show that the characteristic peaks of FcNiOF phase gradually weaken and then completely disappear along with CV activation (Supplementary Fig. 12), consistent with the quasi-amorphous texture observed by HRTEM. In the Raman spectra, two bands at 345 and 605 cm-1 assigned to Fc units disappear completely while two new bands appear at 557 and 684 cm-1 after CV activation, which can be assigned to Ni-O and Fe-O vibrations in FeNiLDH, and moreover the characteristic bands at 1465–1680 cm−1 of carboxyl ligands retain (Fig. 2D). After activation, the Ni-2p XPS spectrum shows the slight bulge on the high binding energy side of characteristic peaks compared to pristine that (Fig. 2E) and reveals a mild increase in Ni3+ content based on the deconvolution analysis. Particularly, the Fe-2p XPS spectra before and after activation are totally different (Fig. 2F), where two characteristic peaks assigned to Fe2+ in Fc units transform into two broad peaks mixed with Fe2+ and Fe3+ in FeNiLDH. The FT-IR spectra show that the vibration bands of Fc groups vanish but the characteristic bands of carboxyl groups remain after CV activation (Supplementary Fig. 13). Meanwhile three extra bands emerge at 640, 880, and 2921 cm−1, which correspond to the Ni-O-H and Fe-O-H bending modes as well as O-H stretching mode in LDH structure, respectively, elucidating the formation of FeNiLDH with carboxyl ligands. The XPS spectra on C−1s and O-1s cores further verify the existence of C = O and C-O bonds in carboxyl groups after CV activation (Supplementary Fig. 14). In addition, the EDS mapping images display the homogeneous distributions of Ni, Fe, C and O in an individual nanosheet (Supplementary Fig. 15), with slightly decreased metal contents with respect to the initial FcNiOF. These results together demonstrate that FcNiOF undergoes the self-reconstruction process, which consists of the distortion of Fc units and the formation of carboxyl-linked FeNiLDH motifs as truly active OER species (Fig. 2G). Thus, FcNiOF represents a pre-catalyst and the reconstructed FeNiLDH with organic framework becomes an actual active catalyst, which is referred to as FeNiHOF hereinafter. It needs to be emphasized that such an activation process can also be conducted by the chronopotentiometry (CP) at a current density of 1 A/cm2 with decreasing overpotential in the initial 10 h (Supplementary Fig. 16). Thus, the activation process to derive the active species is compatible with the actual OER operation, without needs for additional procedure and cost, and here the study on CV activation separately from OER is only to capture the reconstruction information.Note that various NiFe compounds have been generally found to transform into active (oxy)hydroxides (NiFeOxHy) during CV activation and OER processes39,40,41,42,43. But, such anodic reconfiguration is usually accompanied by the dissolution of Fe species due to being peroxidized33,44, resulting in the eventual failure of Ni-Fe synergies. Even the directly synthesized NiFeOxHy also generally suffers from activity attenuation during continuous OER process due to uncontrollable Fe dissolution45, especially at high current densities. In contrast, there was negligible loss in Fe species in above CV activation over FcNiOF, leaving most Fe in the reconstructed NiFeOxHy, which promises the strong robustness toward high-current-density OER. To identify the cause of Fe fixation, we performed the same CV scans for Ni-MOF and Fc-MOF counterparts (Supplementary Fig. 17A), the finally stable products are denoted as NiHOF and FeHOF, respectively. The negligible change of OER activity upon scan cycling is observed for Ni-MOF, although its redox couple of Ni2+/Ni3+ is clearly visible and gradually larger. This means that more high-valence nickel species are generated via reconstruction but no new species to promote OER activity. In contrast, the redox couple of Fc-MOF is not prominent, but its oxidation peak brings closer to the OER onset without the potential gap (i.e., kinetic delay), suggesting that OER activity is higher at the high-valence iron site than at the nickel site. This comparison indicates that Fc component in FcNiOF adjusts the reconstruction product minimizing the kinetic difference between initial metal oxidation and subsequent OER (Supplementary Fig. 17B), responsible for the enhanced activity. Moreover, carboxyl ligands afford more flexible electronic structure for metal sites to avoid being over-oxidized under high anodic potential, consequently adaptive to the CV and OER with high current densities. In addition, we synthesized FeNiLDH via hydrothermal method to conduct similar CV activation (Supplementary Fig. 18), where no new species or ligands were observed after CV activation. It can be concluded that FeNiLDH did not undergo noticeable reconstruction, and its OER performance was inferior compared to FeNiHOF.High-current-density OER performance of FeNiHOFThe electrocatalytic OER performance was assessed by quasi-steady LSV scans at 5 mV s-1 in 1.0 M KOH for FeNiHOF, NiHOF and FeHOF, with commercial RuO2 and Ni foam as references (Fig. 3A and Supplementary Fig. 19). The bare Ni foam shows low current output, indicative of its neglectable contribution to OER activity. Amongst contrast catalysts, FeNiHOF exhibits the highest OER activity with the minimum onset potential and fastest polarization behavior, and reaches an impressive current density up to 2 A/cm2. Specifically, FeNiHOF requires low overpotentials of 273, 280, and 284 mV to deliver current densities of 0.5, 1 and 2 A/cm2, respectively, which are much smaller those of FeHOF, NiHOF, and RuO2 catalysts (Fig. 3B). Moreover, by comparison on overpotentials at high current densities, FeNiHOF outperforms the most of FeNi-based OER catalysts (Supplementary Table 3), showing an outstanding potential for industrial applications. In addition, the bimetallic-component-tuned FexNi1-xHOF (x = 0.3, 0.5, and 0.7) samples all show higher OER activity than monometallic FeHOF and NiHOF (Supplementary Fig. 20), and whereby the topmost activity is screened in FeNiHOF at x = 0.5. This indicates that the Ni-Fe synergy is responsible for the OER enhancement of FeNiHOF, which can also be suggested by the metal redox features prior to the OER in CV curves. As shown in Fig. 3C, NiHOF shows the maximum Ni2+/Ni3+ redox peak but the latest OER initiation and subsequent inferior activity, while the Fc addition enhances the difficulty of Ni oxidation but induces the barrier-free transition into OER and superior activity. Note that monometallic FeHOF does not exhibit obvious metal oxidation peak and commendable OER activity, meaning that single Fe sites are also not competent for OER catalysis. Therefore, bimetallic Ni-Fe synergy is suggested in favor of metal oxidation resistance and OER activity enhancement, consistent with previous findings46,47,48.Fig. 3: Electrochemical OER performance.A LSV curves of FeNiHOF, FeHOF, and NiHOF, with RuO2 and Ni foam as references. Note: \({{\rm{GSA}}}\) is 0.25 cm2; \({{{\rm{R}}}}_{{{\rm{s}}}}\) is 2.1 Ω; see non-iR corrected profiles in Supplementary Fig. 19. B Overpotentials at different current densities. C CV curves of FexNi1-xHOF (x = 0, 0.3, 0.5, 0.7, 1.0). Note: \({{\rm{GSA}}}\) is 0.25 cm2; \({{{\rm{R}}}}_{{{\rm{s}}}}\) is 2.1 Ω; see non-iR corrected profiles in Supplementary Fig. 20. D Tafel plots, (E) EIS Nyquist plots, and F \({C}_{{{\rm{dl}}}}\) values of FeNiHOF, FeHOF, NiHOF and Ni foam. G Gibbs free energy profiles along four-step OER pathway on FeNiHOF and FeNiLDH. H Schematic diagram of OER mechanism. I Charge density difference for FeNiHOF and FeNiLDH. Blue and yellow contours mark electron depletion and accumulation areas, respectively.Tafel plots in Fig. 3D show that FeNiHOF has the smallest slope of 34.8 mV dec-1, compared with FeHOF (58.7 mV dec-1), NiHOF (95.4 mV dec-1), and Ni foam (196.7 mV dec-1), indicating the favorable OER kinetics of FeNiHOF. More importantly, FeNiHOF basically keep such a small Tafel slope unchanged with current density increasing, while other contrast catalysts show the notably increased Tafel slopes especially after current density exceeds 0.5 A/cm2. This demonstrates that FeNiHOF can maintain intrinsic OER kinetics, not restricted by mass/charge transfer for high-current-density catalysis. The EIS Nyquist plots (Fig. 3E) show that FeNiHOF has much smaller \({{{\rm{R}}}}_{{{\rm{ct}}}}\) than FeHOF, NiHOF and Ni foam, indicating high charge transfer kinetics of FeNiHOF. Through non-Faraday CV curves (Supplementary Fig. 21), the double layer capacitances (\({C}_{{{\rm{dl}}}}\)) were evaluated in Fig. 3F, where FeNiHOF exhibits the largest \({C}_{{{\rm{dl}}}}\) and electrochemical surface area (\({{\rm{ECSA}}}\)) among contrast samples. Dynamic wetting images (Supplementary Fig. 22) manifest the superior hydrophilicity on FeNiHOF surface in comparison with Ni foam surface. Dynamic bubbling images (Supplementary Fig. 23) show numerous tiny O2 bubbles detached from FeNiHOF at 1 A/cm2, in which the most are within the size of 0.2–0.3 mm without adhesion on surface, distinct from the bubbling on Ni foam. These results demonstrate that FeNiHOF has the favorable mass/charge transfer kinetics for high-current-density catalysis, benefiting from the ordered porous array architecture. To determine the intrinsic activity of FeNiHOF, the LSV curves were normalized by the \({{\rm{ECSA}}}\) and active-site number (Supplementary Fig. 24), respectively. FeNiHOF exhibits higher \({{\rm{ECAS}}}\)-normalized activity and turnover frequency (\({{\rm{TOF}}}\)) than NiHOF and FeHOF, further verifying Ni-Fe synergistic contribution.To understand the mechanism behind OER kinetics, we constructed and optimized the atomic structures of FeNiHOF and FeNiLDH systems (Supplementary Fig. 25) for theoretical calculations. The spin-resolved projected density of states in Supplementary Fig. 26 show that both FeNiHOF and FeNiLDH have the conductor-like property because the electron states pass through the Fermi levels. The Gibbs free energy profiles along four-step elementary pathways over two systems were calculated using the density function theory (DFT)49,50, with the relaxed structures of different intermediates (Supplementary Fig. 27). The electric potential and solvation effects on free energy calculations were analyzed in Supplementary Fig. 28. The free energy steps shown in Fig. 3G indicate that the rate-determining step (RDS) is the transition of HOO* from O* intermediates for both FeNiHOF and FeNiLDH with different overpotentials (\({{{\rm{U}}}}_{{{\rm{RDS}}}}\)) of 0.56 and 1.13 V, respectively. This suggests that carboxylated metal sites reduce the energy barrier at the RDS (Supplementary Fig. 29), in which the O-O formation by absorbing one OH- at O* intermediate is facilitated with an electron transfer, manifested as third-step acceleration in the OER process (Fig. 3H). The identification of the RDS also accords with the measured Tafel slope as low as 34.8 mV dec-1 51,52,53. We further calculated the charge density difference when metal Fe site adsorbing HOO* intermediate in the highest oxidation states (Fig. 3I). The electronic interaction between the carboxyl ligand and the active metal is demonstrated in FeNiHOF, which mediates the electronic structure around the metal sites responsible for reducing the endothermic energy barrier of the RDS. Moreover, the electronic exchange in carboxyl-linked metal motifs can enhance the applied potential tolerability beneficial to the stability of metal sites. Therefore, the carboxyl conjugation is disclosed to play an important role in optimizing the electronic structure to improve OER kinetics and self-peroxide resistance.The long-term stability of FeNiHOF at high current densities was studied to examine the practical feasibility toward industrial applications. As shown in Fig. 4A, FeNiHOF operates steadily water oxidation without any decay during long-term CP test at 1 A/cm2 for 1000 h. There is no increase in overpotential but instead a slight decrease, probably due to a gain from temperature fluctuation. Real-time online inductively coupled plasma mass spectrometry (ICP) measurements during 100 h CP process at 0.5 A/cm2 confirm the stability of active metal sites in FeNiHOF with considerable dissolution resistance (Fig. 4B, C). The initial Fe loss may be due to a small number of Fe atoms that are not bound by carboxyl groups. In contrast, the same CP test of typical FeNiLDH exhibits an obvious decay with 38% increase in overpotential at 0.5 A/cm2 after 50 h operation (Fig. 4D), meanwhile accompanied by the leakage of metal sites especially Fe ions into the electrolyte (Fig. 4E). This indicates that the carboxyl conjugation in FeNiHOF can provide high charge flexibility to stabilize Fe sites with peroxidation resistance. Non-\({{{\rm{iR}}}}_{{{\rm{s}}}}\) corrected voltammograms for Fig. 4A, B, D are presented in Supplementary Fig. 30. According to the online collection of gas products (Supplementary Fig. 31), the Faraday efficiency (\({{\rm{FE}}}\)) was evaluated by comparing the number of electrons involved in the OER and that transmitted in the circuit (Fig. 4F) to be close to 100%, which means the specific selectivity of FeNiHOF to the OER without side reactions. In addition, the postmortem characterizations of FeNiHOF after durability test reveals that the nanoarray morphology, metal composition and organic linkers almost remain unchanged (Supplementary Fig. 32), further confirming the robust stability of FeNiHOF catalyst. It is worth noting that the catalytic stability at industrial-level high current densities is essential for practical applications, which is rarely reported for MOF-based or NiFe-based catalysts (Supplementary Table 4). Noticeably, the catalytic stability of FeNiHOF is superior to most reported OER catalysts in terms of the current density and duration of continuous operations.Fig. 4: High-current-density durability tests.A Long-term durability test for FeNiHOF in CP model at 1 A/cm2 for 1000 h. Note: \({{\rm{GSA}}}\) is 0.25 cm2; \({{{\rm{R}}}}_{{{\rm{s}}}}\) is 2.1 Ω; see non-iR corrected profiles in Supplementary Fig. 30A. B CP curve at 0.5 A/cm2 and (C) Fe/Ni ionic contents in electrolyte for FeNiHOF. Note: \({{\rm{GSA}}}\) is 0.25 cm2; \({{{\rm{R}}}}_{{{\rm{s}}}}\) is 2.1 Ω; see non-iR corrected profiles in Supplementary Fig. 30B. D CP curve at 0.5 A/cm2 and (E) Fe/Ni ionic contents in electrolyte for FeNiLDH. Note: \({{\rm{GSA}}}\) is 0.25 cm2; \({{{\rm{R}}}}_{{{\rm{s}}}}\) is 2.1 Ω; see non-iR corrected profiles in Supplementary Fig. 30C.Practical application in alkaline water electrolyzerThe hydrothermal method is amenable to scalable synthesis of catalyst electrode at low cost. We could coil and place the flexible Ni foam into a high-volume Teflon-lined stainless autoclave for the scale-up fabrication of FcNiOF electrode. A piece of as-synthesized FcNiOF electrode (9 cm × 10 cm) appears dark yellow color over the whole area, suggesting a uniform growth of FcNiOF nanosheets (Supplementary Fig. 33). Note that the reconstruction from FcNiOF into FeNiHOF would spontaneously take place under OER conditions and require no additional procedures. Based on cheap raw materials and simple preparation process, the price of FeNiHOF electrode is assessed to be only ~147 US$ m-2 (Supplementary Table 5). Combined with its high performance in water oxidation, we believe that Ni foam-supported FeNiHOF as an OER anode has high cost-effectiveness for large-scale application in alkaline water electrolyzers (AWEs). In addition, the flexible Ni foam loaded with the catalyst was tested for mechanical strength through 100 times of bending tests (Supplementary Fig. 34), where no detectable mass loss indicates the reliable adhesion of in-situ grown catalyst on Ni foam, which is critical for gas-bubbling catalysis on electrode.For the current AWE in industry, RANEY nickel (R-Ni) loaded onto nickel wire mesh (NWM) by thermal spray or coating with binders is commonly-used catalyst on the cathode for HER, and the bare NWM is directly used as the anode for OER. In contrast, orderly nanostructured catalysts self-supported on the conductive substrates without binders have been projected to be the most promising promoters for the innovation of AWEs13, but their activity-stability performance under industrial-grade water electrolysis with high current densities (≥0.5 A/cm2) remains uncertain towards practical applications17,18. Herein, we assembled an AWE of FeNiHOF&R-Ni using FeNiHOF and commercial R-Ni as the anode and cathode, respectively, with a diaphragm of polyphenylene sulphide (PPS), to examine its feasibility in actual water electrolysis (Fig. 5A, B). The FeNiHOF&R-Ni electrolyzer requires a cell voltage as low as 1.87 V to achieve a high current density of 1 A/cm2 in 1 M KOH at room temperature, far outperforming an electrolyzer with commercial NWM&R-Ni electrodes (Fig. 5C). Moreover, the cell voltage of the FeNiHOF&R-Ni to deliver a current density of 1 A/cm2 decreases further to 1.81 V when operated in 6 M KOH, while the commercial NWM&R-Ni electrolyzer needs high cell voltages of 2.04–2.26 V to reach industrial-level current densities of 0.5–1 A/cm2 under the same conditions. We further conducted the long-term CP test for the FeNiHOF&R-Ni electrolyzer operated at 1 A/cm2 in 6 M KOH at room temperature with 20 times of ON/OFF switch (Fig. 5D), demonstrating the durability over 500 h with negligible charge in cell voltage. It is worth noting that the electrolyzer at the moment of shutdown usually generates a reverse current, which would deteriorate the durability of catalysts. But the stability study with ON/OFF switch is rarely involved for new-type catalysts so far49,50, which should be concerned when designing catalysts towards industrial applications. The excellent performance suggests the potential of industrialized AWE with cost-effective FeNiHOF anode. The power consumption (\({{\rm{W}}}\)) and energy efficiency (\({{\rm{ETH}}}\)) of FeNiHOF&R-Ni are calculated to be ~4.23 kW h Nm-3 and ~83.6% at 0.5 A/cm2 at 1.77 V (Fig. 5E), superior to those of commercial NWM&R-Ni (4.88 kW h Nm-3; 72.5%). The H2 yield rate (\({{\rm{R}}}\)) is around 3.18 Nm3 h−1 m-2 for the FeNiHOF&R-Ni at 1.8 V, higher than that for the NWM&R-Ni (0.45 Nm3 h-1 m-2). Moreover, for the FeNiHOF&R-Ni electrolyzer, the price of producing H2 is estimated to be approximately US$ 1.01 per gallon of gasoline equivalent (GGE), which is much less than the 2026 technical goal (US$ 2.00) from the Department of Energy in United States54. Finally, we comprehensively summarize the performance in terms of cell voltage, stability time, \({{\rm{W}}}\), \({{\rm{ETH}}}\), and \({{\rm{R}}}\) in Supplementary Table 6, where the AWE enabled by FeNiHOF catalyst stands out from the state-of-the-art AWEs reported in the literatures. Note that only the anode is replaced by FeNiHOF in our electrolyzer and the cathode is still the commercial standard R-Ni in order to highlight the effect of anode substitution, different from most advanced electrolyzers reported with dual electrode substitution (Supplementary Table 6). If meanwhile employing high-performance alternatives to R-Ni, the AWEs would have further room for performance improvement.Fig. 5: Practical application in alkaline water electrolyzer.A Stack structure and (B) photograph of FeNiHOF&R-Ni electrolyzer. C LSV curves of FeNiHOF&R-Ni and NWM&R-Ni electrolyzers with flowing electrolytes of 1 M and 6 M KOH. D Long-term CP curve of FeNiHOF&R-Ni electrolyzer at 1 A/cm2 in 6 M KOH. E Energy efficiency contrast between FeNiHOF&R-Ni and commercial NWM&R-Ni electrolyzers.
