High-performance Oxygen Evolution Reaction Research Articles

Boron-Induced Interstitial Effects Drive Water Oxidation on Ordered Ir-B Compounds.

Interstitial filling of light atoms strongly affects the electronic structure and adsorption properties of the parent catalyst due to ligand and ensemble effects. Different from the conventional doping and surface modification, constructing ordered intermetallic structures is more promising to overcome the dissolution and reconstruction of active sites through strong interactions generated by atomic periodic arrangement, achieving joint improvement in catalytic activity and stability. However, for tightly arranged metal lattices, such as iridium (Ir), obtaining ordered filling atoms and further unveiling their interstitial effects are still limited by highly activated processes. Herein, we report a high-temperature molten salt assisted strategy to form the intermetallic Ir-B compounds (IrB1.1)with ordered filling by light boron (B) atoms. The B residing in the interstitial lattice of Ir constitutes favorable adsorption surfaces through a donor-acceptor architecture, which has an optimal free energy uphill in rate-determining step (RDS) of oxygen evolution reaction (OER), resulting in enhanced activity. Meanwhile, the strong coupling of Ir-B structural units suppresses the demetallation and reconstruction behavior of Ir, ensuring catalytic stability. Such B-induced interstitial effects endow IrB1.1 with higher OER performance than commercial IrO2, which is further validated in proton exchange membrane water electrolyzers (PEMWEs).

Boron‐Induced Interstitial Effects Drive Water Oxidation on Ordered Ir‐B Compounds

Interstitial filling of light atoms strongly affects the electronic structure and adsorption properties of the parent catalyst due to ligand and ensemble effects. Different from the conventional doping and surface modification, constructing ordered intermetallic structures is more promising to overcome the dissolution and reconstruction of active sites through strong interactions generated by atomic periodic arrangement, achieving joint improvement in catalytic activity and stability. However, for tightly arranged metal lattices, such as iridium (Ir), obtaining ordered filling atoms and further unveiling their interstitial effects are still limited by highly activated processes. Herein, we report a high‐temperature molten salt assisted strategy to form the intermetallic Ir‐B compounds (IrB1.1) with ordered filling by light boron (B) atoms. The B residing in the interstitial lattice of Ir constitutes favorable adsorption surfaces through a donor‐acceptor architecture, which has an optimal free energy uphill in rate‐determining step (RDS) of oxygen evolution reaction (OER), resulting in enhanced activity. Meanwhile, the strong coupling of Ir‐B structural units suppresses the demetallation and reconstruction behavior of Ir, ensuring catalytic stability. Such B‐induced interstitial effects endow IrB1.1 with higher OER performance than commercial IrO2, which is further validated in proton exchange membrane water electrolyzers (PEMWEs).

IrO2 Oxygen Evolution Catalysts Prepared by an Optimized Photodeposition Process on TiO2 Substrates.

Preparing high-performance oxygen evolution reaction (OER) catalysts with low precious metal loadings for water electrolysis applications (e.g., for green hydrogen production) is challenging and requires electrically conductive, high-surface-area, and stable support materials. Combining the properties of stable TiO2 with those of active iridium oxide, we synthesized highly active electrodes for OER in acidic media. TiO2 powders (both commercially available Degussa P-25® and hydrothermally prepared in the laboratory from TiOSO4, either as received/prepared or following ammonolysis to be converted to titania black), were decorated with IrO2 by UV photodeposition from Ir(III) aqueous solutions of varied methanol scavenger concentrations. TEM, EDS, FESEM, XPS, and XRD measurements demonstrate that the optimized version of the photodeposition preparation method (i.e., with no added methanol) leads to direct deposition of well-dispersed IrO2 nanoparticles. The electroactive surface area and electrocatalytic performance towards OER of these catalysts have been evaluated by cyclic voltammetry (CV), Linear Sweep Voltammetry (LSV), and Electrochemical Impedance Spectroscopy (EIS) in 0.1 M HClO4 solutions. All TiO2-based catalysts exhibited better mass-specific (as well as intrinsic) OER activity than commercial unsupported IrO2, with the best of them (IrO2 on Degussa P-25® ΤiO2 and laboratory-made TiO2 black) showing 100 mAmgIr-1 at an overpotential of η = 243 mV. Chronoamperometry (CA) experiments also proved good medium-term stability of the optimum IrO2/TiO2 electrodes during OER.

Influence of Oxygen Vacancies in La0.4Sr0.6FeO3-δ Perovskite Oxide Nanoparticles for the Oxygen Evolution Reaction

Oxygen vacancies are important factors to tune the performance of oxide catalysts for the oxygen evolution reaction (OER). However, it remains challenging how to control the concentration of the oxygen vacancies and decouple their effects on OER from other factors. In this work, we use a specific composition/phase La0.4Sr0.6FeO3- d perovskite oxide as an example to tailor the oxygen vacancies of their nanoparticulate using a modified molten salt synthesis and ozone treatment. The OER performance of the resulting La0.4Sr0.6FeO3- d nanoparticles with different degree of oxygen vacancies ranging from 0 to 25% are compared. The OER reactivity increases with increased oxygen vacancies in the materials, but the change is nonlinear. The OER stability, on the other hand, has a bimodal distribution. The activities of fully oxidized sample and the most oxygen-deficient sample degrade slower than the two samples in the middle. The results suggest that it is feasible to design catalysts with oxygen vacancy to be the most OER active and stable. Further investigation into the oxygen vacancy – active site relation would offer guiding principle to design and synthesize high OER performance oxide catalysts.

Substantial Electrocatalytic Oxygen Evolution Performances of Activated Carbon-Decorated Vanadium Pentoxide Nanocomposites

Developing the ecofriendly and high-fidelity electrocatalysts for the oxygen evolution reaction (OER) is essential to foster effective production of environmentally friendly hydrogen. Herein, we fabricated the highly efficient OER electrocatalysts of the activated carbon-decorated vanadium pentoxide (AC-V2O5) nanocomposites using a facile hydrothermal technique. The AC-V2O5 nanocomposites displayed an aggregated structure of the AC nano-sheet-anchored orthorhombic V2O5 nanorods. When performing the OER process in an alkaline electrolyte at 10 mA/cm2, AC-V2O5 exhibited the low overpotential (~230 mV), small Tafel slope (~54 mV/dec), and excellent stability. These substantial OER performances of AC-V2O5 could be ascribed to the synergistic effects from both the electrochemically active V2O5 nanorods and the highly conductive AC nanosheets. The results infer that the AC-V2O5 nanocomposites possess a substantial aptitude as a high-performance OER electrocatalyst for production of the future green energy source—hydrogen.

Ti3C2 mediates the NiFe-LDH layered electrocatalyst to enhance the OER performance for water splitting

Oxygen evolution reaction (OER) is a very complex process with slow reaction kinetics and high overpotential, which is the main limitation for the commercial application of water splitting. Thus, it is of necessary to design high-performance OER catalysts. NiFe based layered double hydroxides (NiFe-LDHs) have recently gained a lot of attention due to their high reaction activity and simple manufacturing process. In this study, a novel electrocatalyst based on NiFe-LDH was constructed by introducing Ti3C2, which was utilized to modulate the structural and electronic properties of the electrocatalysts. Structural examinations reveal that the Ti3C2 of 2D structure successfully dope the NiFe-LDHs nanosheets, forming NiFe-LDH/Ti3C2 heterojunctions. Firstly, the heterojunction substantially reduces the charge transfer resistance, promoting the electron migration between the LDH nanosheets. Secondly, theoretical calculations demonstrate that the energy barrier between the rate-determining step from *OH to *O is lowered, favoring the formation of the reaction intermediates and thus the occurrence of OER. As a result, the composite electrocatalyst exhibits a low overpotential of 334 mV at a current density of 10 mA/cm2 and a small Tafel slope of 55 mV/dec, which are superior to those of the NiFe-LDH by 11.2 % and 38.5 %, respectively. This study provides inspiration for promoting the performances of NiFe based electrocatalysts by utilizing 2D materials.

Superhydrophilic NiFe-LDH@Co9S8-Ni3S2/NF heterostructures for high-current-density freshwater/seawater oxidation electrocatalysts

Designing oxygen evolution reaction (OER) electrocatalysts with high efficiency and stability at large current densities is paramount for achieving hydrogen production through water splitting. In this study, a heterostructured NiFe-LDH coating Co9S8-Ni3S2 grown on nickel foam (NiFe-LDH@Co9S8-Ni3S2/NF) was successfully synthesized. The distinctive hierarchical structures featuring abundant heterointerfaces can effectively expose abundant active sites. The synergistic effect and strong electronic interaction between Co9S8-Ni3S2 and NiFe-LDH can enhance the intrinsic OER activity. Furthermore, the superhydrophilic characteristic of NiFe-LDH@Co9S8-Ni3S2/NF favors close contact between the electrode and electrolyte. Due to these advantages, NiFe-LDH@Co9S8-Ni3S2/NF can provide distinguished OER activity with low overpotentials of 274 mV in alkaline freshwater and 298 mV in alkaline seawater at 1000 mA cm−2, along with outstanding stability at high current density of 500 mA cm−2 over 200 h in both solutions. This study offers a valuable insight into fabricating high-performance OER electrocatalysts for seawater electrolysis in industrial applications.

Co-doped NiFe carbonate hydroxide hydrate nanosheets with edge effect constructed from spent lithium-ion battery ternary cathodes for oxygen evolution reaction

The recycling of spent lithium-ion batteries (LIBs) has received increasing attention for environment and resource reclamation. Converting LIBs wastes into high-efficiency catalysts is a win-win strategy for realizing resource reclamation and addressing sustainable energy challenges. Herein, we developed a simple method to upcycle spent-LIBs cathode powder into Co-doped NiFe carbonate hydroxide hydrate (Co/NFCH-FF) as a low-cost and efficient oxygen evolution reaction (OER) electrocatalyst. The optimized Co/NFCH-FF electrode appears very competitive OER performances with low overpotentials of 201 and 249 mV at 10 and 100 mA cm−2, respectively, a small Tafel slope of 48.4 mV dec−1, and a high long-term stability. Moreover, we reveal that the existence of Co atoms leads to the formation of a crystalline/amorphous (c/a) interface at the Co/NFCH nanosheet edge, inducing the nanosheets possess a unique edge effect to enhance electric fields and accumulate hydroxide ions (OH–) at the edge during the OER process. Benefiting from edge effect, Co/NFCH-FF shows outstanding intrinsic activity. Furthermore, Co atoms as dopants stabilize the electronic structure of Co/NFCH-FF, enabling Co/NFCH-FF to exhibit excellent catalytic stability. This work provides an effective strategy for converting the end-life LIBs to high-performance multicomponent OER electrocatalysts and proposes new insights into the mechanism of enhanced catalytic activity of Co/NFCH.

Molybdenum sulfide/Ni:FeOOH heterostructures as efficient water oxidation electrocatalysts in alkaline media

Sluggish oxygen evolution reaction (OER) is considered to be the bottleneck that restricts the usage of electrocatalytic water splitting to generate hydrogen. With this in mind, we demonstrate the design and preparation of a series of Mo15S19/Ni:FeOOH heterostructures toward water oxidation. As expected, the considerable acceleration of OER process is achieved by the combination of Mo15S19 with Ni:FeOOH, due to the formation of heterojunction. Under the optimized conditions, the as-prepared Mo15S19/Ni:FeOOH-21 exhibits a lower overpotential (214 mV vs RHE at 10 mA cm−2) than other control samples. The OER activity of Mo15S19/Ni:FeOOH-21 is found to be comparable to and/or better than the state-of-the-art OER electrocatalysts reported in the literature recently, making it a promising OER electrocatalyst in the industrial water electrolysis. This work opens up an efficient avenue to rational design of other high-performance composite OER electrocatalysts.

Unveiling the Potential of Covalent Organic Framework Electrocatalyst for Enhanced Oxygen Evolution.

The potential for sustainable energy and carbon neutrality has expanded with the development of a highly active electrocatalyst for the oxygen evolution reaction (OER). Covalent Organic Frameworks (COF) have recently garnered attention because of their enormous potential in a number of cutting-edge application sectors, such as gas storage, sensors, fuel cells, and active catalytic supports. A simple and effective COF constructed and integrated by post-alteration plasma modification facilitates high electrocatalytic OER activity under alkaline conditions. Variations in parameters such as voltage and treatment duration have been employed to enhance the factor that demonstrates high OER performance. The overpotential and Tafel slope are the lowest of all when using an optimized parameter, such as plasma treatment for 30 min utilizing 6 kV of voltage, PT-30 COF, measuring 390 mV at a current density of 10 mA.cm-2 and 69 mV.dec-1, respectively, as compared to 652 mV and 235 mV.dec-1 for the Pristine-COF. Our findings provide a method for broadening the scope by post-functionalizing the parent framework for effective water splitting.

Guided Design of Efficient Oxygen Evolution Catalysts Using Patent Analysis.

The facile and rapid design of efficient oxygen evolution reaction (OER) catalysts holds paramount significance for energy conversion devices, such as water electrolyzers and fuel cells. Despite substantial progress in catalyst synthesis and performance exploration, the design and selection processes remain inefficient. In this context, we integrate patent analysis with catalyst design, leveraging the scholarly research functionalities within patent analyses to aid in the design and synthesis of a NiFeRu-carbon catalyst as a high-performance OER catalyst. The results demonstrate that the NiFeRu-Carbon catalyst with low Ru loading (0.3 wt %) exhibits an overpotential of only 219 mV at 10 mA cm-2 under alkaline conditions, and after continuous operation for 200 h, the overpotential only attenuates by 15 mV. The incorporation of high-valence Ru dopants elevated the intrinsic activity of individual catalytic sites within NiFe-layered double hydroxides (LDHs). During the catalytic process, the partial dissolution of Ru might lead to the generation of numerous oxygen vacancies within NiFe- LDH, thereby enhancing the catalyst's activity and stability.

Constructing interlaced network structure by grain boundary corrosion methods on CrCoNiFe alloy for high-performance oxygen evolution reaction and urea oxidation reaction

Corrosion engineering is an effective way to improve the oxygen evolution reaction (OER) activity of alloys. However, the impact of grain boundary corrosion on the structure and electrochemical performance of alloy is still unknown. Herein, the vacuum arc-melted CrCoNiFe alloys with interlaced network structures via grain boundary corrosion methods were fabricated. The grain boundaries that existed as defects were severely corroded and an interlaced network structure was formed, promoting the exposure of the active site and the release of gas bubbles. Besides, the (oxy)hydroxides layer (25 nm) on the surface could act as the true active center and improve the surface wettability. Benefiting from the unique structure and constructed surface, the CrCoNiFe-12 affords a high urea oxidation reaction (UOR) performance with the lowest overpotential of 250 mV at 10 mA/cm2 in 1 M KOH adding 0.33 M urea. The CrCoNiFe-12||Pt only required a cell voltage of 1.485 V to afford 10 mA/cm2 for UOR and long-term stability of 100 h at 10 mA/cm2 (27.6 mV decrease). These findings offer a facile strategy for designing bulk multiple-principal-element alloy electrodes for energy conversion.

Moderately Reconstructed Ternary Metal Nitride Nanoparticles for Highly Efficient and Robust Freshwater and Seawater Oxidation under Industrial Current Density

Transition metal nitrides (TMNs) electrocatalysts experience rapid performance degradation during oxygen evolution reaction (OER) due to severe and irreversible electrochemical reconstruction, impeding their practical application in electrochemical water splitting. To address this issue, ternary metal (Ni, Fe, Cr) nitride nanoparticles on spongy nitrogen‐doped disordered carbon skeleton electrocatalyst (NFCN/C) is synthesized using a novel one‐pot pyrolysis of eutectic mixture method. The ionomer‐free NFCN/C electrode, which undergoes moderate electrochemical reconstruction, demonstrates high OER performance in both alkaline freshwater and seawater solutions, achieving a current density of 250 mA cm−2 with low overpotentials of 349 and 364 mV, respectively. The NFCN/C anode with Pt/C cathode delivers 10 mA cm−2 at a low cell voltage of 1.49 V and exhibits long‐term durability of 450 h at 500 mA cm−2. In situ Raman spectroscopy and ultraviolet photoelectron spectroscopy (UPS), along with pre‐ and post‐characterizations, elucidate that both high electrocatalytic activity and robustness of NFCN/C for OER stem from the proposed intrinsic strategy integrating physical and electronic structures. This work paves the way for designing highly efficient and robust TMNs electrocatalysts with moderate electrochemical reconstruction for industrial freshwater and seawater electrolysis.

Enhanced oxygen evolution reaction of electrodeposited Functionally-Graded Ni-Cu-Fe coating

This study aimed to use a functionally graded (FG) Ni-Cu-Fe coating as an electrocatalyst for oxygen evolution reaction (OER) applications. The coating was applied on a mild carbon steel substrate by an electrodeposition technique, with the current density being progressively increased from 0.5 A/dm2 to 5 A/dm2 at a steady rate of 0.2 (A/dm2)/min during the coating operation. Using this specific method, the Ni content of the FG Ni-Cu-Fe coating changed along the cross-section when increasing the current density, 17 % more than the constant current coating. This technique also affected the surface morphology of the FG Ni-Cu-‌Fe coating and changed it from cauliflower to micro/nanocones when the current density was linearly increased, enhancing active sites significantly and thereby improving electrocatalytic activity. The coating's electrocatalytic behavior was studied by electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and cyclic voltammetry (CV). results showed that the FG Ni-Cu-Fe coating had the smallest overpotential (134 mV) at the current density of 10 mA.cm−2. Also, it had the smallest Tafel slope (24.3 mV.dec− 1) and smallest resistance (598 Ω.cm2) compared to all of the other coatings. The FG Ni-Cu-‌‌Fe coating had higher OER performance because of high Ni content, micro/nanocones morphology with many active sites, and FG nature. The FG Ni-Cu-Fe coating is finally concluded to be a promising and economical catalyst with high OER activity.

Theoretical study on oxygen evolution reaction mechanism of double rare earth europium-doped graphene under hydroxyl modification in alkaline environment

The development and design of high performance OER catalyst is the key to electrocatalysis technology. Herein, based on density functional theory (DFT), the oxygen evolution reaction mechanism of double rare earth europium-doped graphene under hydroxyl modification in alkaline environment has been systematically studied. Through thermodynamic and kinetic stability analysis, and the optimal reaction path and different adsorption sites of intermediates were compared. Four catalysts with good catalytic activity for OER reaction were selected. The results show that when the two hydroxyl groups are modified, the overpotentials on the optimal pathway for the four catalyst configurations are 0.54 V, 0.50 V, 0.54 V, and 0.61 V, respectively. These catalysts demonstrate excellent catalytic activity for the oxygen evolution reaction (OER). Moreover, these catalysts have good electrical conductivity, and the active site and adsorption intermediates can be stably bonded together. In addition, the scaling relationship between oxygen adsorption free energy and overpotential is described. This work may provide new insights and guidance for future research on rare-earth atom-based OER catalysts.

Molten salt electrosynthesis of self-supporting FeCoNi medium entropy alloy electrocatalysts for efficient oxygen evolution reactions

High/medium entropy alloys (HEAs/MEAs) with high electrocatalytic activity have attracted great attention in water electrolysis applications. However, facile synthesis of self-supporting high/medium entropy alloys electrocatalysts with rich active sites through classical metallurgical methods is still a challenge. Here, a self-supporting porous FeCoNi MEA electrocatalyst with nanosheets-shaped surface for oxygen evolution reaction (OER) was prepared by a one-step electrochemical process from the metal oxides in molten CaCl2. The formation of the FeCoNi MEA is attributed to the oxides electro-reduction, high-temperature diffusion and solid solution. Additionally, the morphology and structure of the FeCoNi MEA can be precisely controlled by adjusting the electrolysis time and temperature. The electronic structure regulation and the reduced energy barrier of OER from the “cocktail effect”, the abundant exposed active sites brought by surface ultrathin nanosheets, the good electronic conductivity and electrochemical stability from the self-supporting structure enable the FeCoNi MEA electrode shows high-performance OER electrocatalysis, exhibiting a low overpotential of 233 mV at a current density of 10 mA cm–2, a low Tafel slope of 29.8 mV dec–1, and an excellent stability for over 500 h without any obvious structural destruction. This work demonstrates a facile one-step electrochemical metallurgical approach for fabricating self-supporting HEAs/MEAs electrocatalysts with nanosized surface for the application in water electrolysis.

High-performance oxygen evolution reaction via self-optimizing interface engineering with simultaneous activation of dual-sites of surface oxyhydroxides

Metal oxyhydroxides produced by the surface reconstruction were widely considered as active catalytic species in the oxygen evolution reaction (OER). However, simultaneous activation of metal sites in surface oxyhydroxides remains a great challenge. In this study, the interface self-activation strategy was utilized to simultaneously activate both the iron and nickel sites at the surface oxyhydroxides of (Fe,Ni)OOH-NiSe2 nano heterostructure. The OER activity was greatly boosted by the dual activation of active sites, resulting in an overpotential of 245 mV@100 mA cm−2 with a small Tafel slope of 44 mV dec−1. The finely constructed FeOOH-NiSe2 heterostructure was transformed into (Fe,Ni)OOH-NiSe2 through the formation of distinct bonds of M(Fe,Ni)-O-Se during the OER process, which was discovered through a combination of experimental studies with DFT calculations. A fast OER reaction dynamic was achieved due to the unique self-optimized interface structure which produced a dual synergistic effect between the interface structure and the active sites of Fe and Ni of oxyhydroxides, modulated the electronic structure and d band center of active sites, and increased the number of optimum active sites. This work paves a way to design high-performance electrocatalysts with multiple active sites for other electrochemical reactions.

Modulating Electronic Structure of Iridium Single-Atom Anchored on 3D Fe-Doped β-Ni(OH)2 Catalyst with Nanopyramid Array Structure for Enhanced Oxygen Evolution Reaction.

Developing high-performance electrocatalysts for oxygen evolution reaction (OER) is crucial in the pursuit of clean and sustainable hydrogen energy, yet still challenging. Herein, a spontaneous redox strategy is reported to achieve iridium single-atoms anchored on hierarchical nanosheet-based porous Fe doped β-Ni(OH)2 pyramid array electrodes (SAs Ir/Fe-β-Ni(OH)2 ), which exhibits high OER performance with a low overpotential of 175mV at 10mAcm-2 and a remarkable OER current density in alkaline electrolyte, surpassing Fe-β-Ni(OH)2 /NF and IrO2 by 31 and 38 times at 1.43V versus RHE, respectively. OER catalytic mechanism demonstrates that the conversion of * OH→* O and the active lattice O content can be significantly improved due to the modulation effect of the Ir single atoms on the local electronic structure and the redox behavior of FeNi (oxy) hydroxide true active species. This work provides a promising insight into understanding the OER enhancement mechanism for Ir single-atoms modified FeNi-hydroxide systems.

Effect of Ni Sulfate Residue on Oxygen Evolution Reaction (OER) in Porous NiFe@NiFe Layered Double Hydroxide.

The development of cost-effective and high-performance oxygen evolution reaction (OER) catalysts is a significant challenge. This study presents the synthesis of binder-free NiFe@NiFe layered double hydroxide (NNF) via one-pot electrodeposition on carbon paper and Ni foam at high current densities. The presence of Ni sulfate residues on the prepared NNF is also investigated. The findings indicate that Ni sulfate significantly improves OER performance and durability. The sulfate content can be controlled by varying the method and duration of washing. NNF prepared through dipping (NNF-D) exhibits outstanding OER activity with a low overpotential of 241mV, which is 25mV lower than that of NNF washed for 60s (NNF-W-60s) at 10mAcm-2 in 1m KOH. Furthermore, density functional theory analyses indicate that the Ni sulfate residue helps modify the electronic structure, thereby optimizing the binding strength of *OOH. This synthetic strategy is expected to inspire the development of next-generation catalysts utilizing various adsorbates.

Silver Nanowires Cascaded Layered Double Hydroxides Nanocages with Enhanced Directional Electron Transport for Efficient Electrocatalytic Oxygen Evolution.

Designing and fabricating highly efficient oxygen evolution reaction (OER) electrocatalytic materials for water splitting is a promising and practical approach to green and sustainable low-carbon energy systems. Herein, a facile in situ growth self-template strategy by using ZIF-67 as a consumable layered double hydroxides (LDHs) template and silver nanowires (AgNWs) as 1D conductive cascaded substrate to controllably synthesize the target AgNWs@CoFe-LDH composites with unique hollow shell sugar gourd-like structure and enhanced directional electron transport effect is reported. The AgNWs exhibit the key functions of the close connection of CoFe-LDH nanocages and the support of the directional electron transport effect in the composite catalyst inducing electrons directionally moving from CoFe-LDH to AgNWs. Meanwhile, the CoFe-LDH nanocages with ultrathin nanosheets and hollow structural properties show abundant active sites for electrocatalytic oxygen generation. The versatile AgNWs@CoFe-LDH catalyst with optimized components, enhanced directional electron transport, and synergistic effect achieves high OER performance with the overpotential of 207 mV and long-term 50 h stability at 10 mA cm-2 in an alkaline medium. Moreover, in-depth insights into the microstructure, structure-activity relationships, identification of key intermediate species, and a proton-coupled four-electron OER mechanism based on experimental discovery and theoretical calculation are also demonstrated.