Self-supported cobalt–molybdenum oxide nanosheet clusters as efficient electrocatalysts for hydrogen evolution reaction

In this paper, we report the three-dimensional self-supported CoMoO₄ nanosheet clusters on the nickel foam (denoted as CoMoO₄/NF) by a facile hydrothermal-calcination method for efficient hydrogen generation. As a result, the freestanding CoMoO₄ electrode exhibits an efficient electrochemical activity towards hydrogen evolution reaction, showing overpotentials as low as 68 and 178 mV at current densities of 10 and 100 mA cm⁻² in the alkaline condition (1 M KOH), respectively, a Tafel slope value of 82 mV per decade. Moreover, the electrode exhibits remarkable electrochemical durability for 1000 cycles. Significantly, the water splitting electrolyzer assembled with CoMoO₄/NF || NiFe LDH/NF (the nickel iron layered double hydroxide supported on the nickel foam) system achieved 20 mA cm⁻² at 1.63 V, showing the CoMoO₄/NF is promising for practical water splitting applications.     

Phase transition in V-doped cobalt hydroxide for efficient oxygen evolution and urea oxidation reaction

In this work, many kinds of V doped Co(OH)₂ electrodes were in situ synthesized on Ni foam by a one-step typical hydrothermal process. It is worth noting that the phase transition composition of the V doped Co(OH)₂ material can be modulated by the difference of the amount of the V introduced. Different crystal phase compositions show different water oxidation activities. It is worth noting that the V2–Co(OH)₂/NF electrode shows better oxygen evolution performance (Overpotential of 320 mV@50 mA cm⁻²) compared with Co(OH)₂/NF (450 mV@50 mA cm⁻²), V1–Co(OH)₂/NF (340 mV@50 mA cm⁻²) and V3–Co(OH)₂/NF (350 mV@50 mA cm⁻²) electrodes. The experimental results show that not all doping can improve the electrochemistry performance of electrodes, such as the oxidation of urea. Density functional theory calculation further proves that the doping of the V is favorable to the adsorption of water and inhibits the adsorption of urea. This study provides a new idea for the development of efficient overall water splitting catalysts.     

Vertical Nickel–Iron layered double hydroxide nanosheets grown on hills-like nickel framework for efficient water oxidation and splitting

Herein, the vertical thin nickel–iron layered double hydroxide nanosheets grown on the hills-like nickel framework (NiFe LDH/Ni@NF) are employed for the oxygen evolution reaction (OER), securing at the low overpotentials of 197 and 270 mV to obtain the current densities of 20 and 100 mA cm⁻², respectively, with a Tafel slope of 73.34 mV dec⁻¹. The electrodeposited nickel film induces the NiFe LDH nanosheets grow vertically and thinly. As well, the nickel abundant interfaces and inner space makes this catalyst effective for OER. It was further served as the OER electrode in a water splitting system coupled the Pt/C cathode, and a cell voltage was at 1.52 and 1.67 V to achieve the current density of 10 mA cm⁻² and 50 mA cm⁻². In addition, the water electrolyzer can suffer a long time of 24 h at 50 mA cm⁻², showing the feasibility in a practical unbiased alkaline water splitting system.     

Cu2S/Ni3S2 ultrathin nanosheets on Ni foam as a highly efficient electrocatalyst for oxygen evolution reaction

It is an inevitable choice to find efficient and economically-friendly electrocatalysts to reduce the high overpotential of oxygen evolution reaction (OER), which is the key to improve the energy conversion efficiency of water splitting. Herein, we synthesized Cu₂S/Ni₃S₂ catalysts on nickel foam (NF) with different molar ratios of Ni/Cu by a simple two-step hydrothermal method. Cu₂S/Ni₃S₂-0.5@NF (CS/NS-0.5@NF) effectively reduces the overpotential of OER, displaying small overpotentials (237 mV@100 mA cm^?2 and 280 mV@500 mA cm^?2) in an alkaline solution, along with a low Tafel slope of 44 mV dec^?1. CS/NS-0.5@NF also presents an excellent durability at a relatively high current density of 100 mA cm^?2 for 100 h. The excellent performance is benefited by the prominent structural advantages and desirable compositions. The nanosheet has a high electrochemical active surface area and the porous structure is conducive to electrolyte penetration and product release. This work provides an economically-friendly Cu-based sulfide catalyst for effective electrosynthesis of OER.     

One-step gas phase sulfided NiFe coating as self-supporting electrode for high efficiency oxygen evolution reaction

The development of cost-effective oxygen evolution reaction (OER) electrocatalytic electrodes is one of the essential means of applying green hydrogen energy. Due to the complex steps in the anodic OER, the high overpotential hinders the kinetics of water splitting. In this paper, the sulfided NiFe coating was innovatively designed as a self-supporting OER electrode by high-velocity oxygen fuel (HVOF) spraying coupled with one-step gas phase sulfuration. The thickness of the NiFe coating is approximately 20 μm. After the sulfuration treatment, the surface of the NiFe coating is remolded into a uniform rock sugar-like structure, and simultaneously forms new NiS and Ni₃S₄ phases. The sulfided NiFe coating electrode shows relatively low overpotentials of 220 mV and 253 mV at the current density of 10 mA cm⁻² and 100 mA cm⁻², respectively, and the Tafel slope is as low as 28.6 mV dec⁻¹. The excellent electrocatalytic activity is mainly attributed to the synergistic effect of sulfides, the adsorption of OH⁻ by the Ni³⁺ in alkaline electrolyte, and the acceleration of O₂ separation by the S²⁻ through promoting the cleavage of O–O bonds. In addition, the sulfided NiFe coating electrode also has a small charge transfer resistance, and the potential stability is as high as 98.1% in the 70 h stability test. Therefore, the development of sulfided transition metal coating electrodes can provide a new idea for the large-scale industrialization of water splitting.     

Sulfuration of hierarchical Mn-doped NiCo LDH heterostructures as efficient electrocatalyst for overall water splitting

Constructing efficient bifunctional electrocatalysts for both cathode and anode is of great importance for obtaining green hydrogen by water splitting. Herein, sulfuration of hierarchical Mn-doped NiCo LDH heterostructures (Mn–NiCoS₂/NF) is constructed as a bifunctional electrocatalyst for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) via a facile hydrothermal-annealing strategy. Mn–NiCoS₂/NF shows an overpotential of 310 mV at 50 mA cm⁻² for OER and 100 mV at 10 mA cm⁻² for HER in 1.0 M KOH. Moreover, only 1.496 V@10 mA cm⁻² is required for overall water splitting by using Mn–NiCoS₂/NF as catalyst dual electrodes in a two-electrode system. The excellent performance of Mn–NiCoS₂/NF should be attributed to the ameliorative energy barriers of adsorption/desorption for HO⁻/H₂O through the modification of electronic structure of NiCo basal plane by Mn-doping and the acceleration of water dissociation steps via rich delocalized electron inside sulfur vacancies. The construction of hierarchical Mn–NiCoS₂/NF heterostructures provides new prospects and visions into developing efficient-advanced electrocatalysts for overall water splitting.     

CoO/NF nanowires promote hydrogen and oxygen production for overall water splitting in alkaline media

The exploration of catalysts with high activity and low cost for water splitting is still necessary. Herein, a nanowire-like morphology CoO/NF electrode is synthesized using facile hydrothermal reaction and calcination treatment. The urea can regulate its morphology during the synthetic process of CoO/NF. Electrochemical studies reveal that the as-obtained CoO/NF exhibits excellent electrocatalytic performance with overpotential of 307 mV at current density of 10 mA cm⁻² and Tafel slope of 72 mV dec⁻¹ for oxygen evolution reaction, and CoO/NF delivers current density of 10 mA cm⁻² at overpotential of 224 mV for hydrogen evolution reaction. The results of the oxygen evolution reaction stability show that the overpotential of CoO/NF electrode is only increased by 4 mV at current density of 10 mA cm⁻². The two-electrode water splitting with CoO/NF electrodes as both anode and cathode needs a cell potential of 1.76 V to reach 10 mA cm⁻². Therefore, this simple method to prepare CoO/NF electrode can enhance the properties of electrocatalysts, which makes CoO/NF a promising material to replace noble metal-based catalysts.     

Synthesis of non-noble NiMoO4–Ni(OH)2/NF bifunctional electrocatalyst and its application in water-urea electrolysis

Electrochemical water splitting to produce hydrogen is one of the most important technologies for energy storage and conversion. Urea oxidation reaction (UOR) with a lower electrode potential instead of oxygen evolution reaction (OER, water-splitting anode) in the water-urea electrolysis is an energy-saving approach. In this paper, NiMoO₄–Ni(OH)₂/NF is synthesized by hydrothermal reactions and explored as both hydrogen evolution reaction (HER) and UOR catalyst electrodes. This composite catalyst shows high catalytic bifunctional activities towards both HER and UOR. To validate both catalytic UOR and HER activities and durability, a two-electrode water-urea electrolyzer composed of NiMoO₄–Ni(OH)₂/NF as both anode and cathode materials is constructed (NiMoO₄–Ni(OH)₂/NF||NiMoO₄–Ni(OH)₂). Experiments show that a voltage of 1.341 V with a high stability (over 3000 CV cycles) can be achieved at 10 mA cm⁻², which are much better than those obtained using a Pt/C||IrO₂.     

CoSe2@NiSe2 nanoarray as better and efficient electrocatalyst for overall water splitting

Electrocatalytic water splitting is identified as one of the most promising solutions to energy crisis. The CoSe₂@NiSe₂ materials were first prepared and in situ grown on nickel foam by typical hydrothermal and selenification process at 120 °C. The results show that the CoSe₂@NiSe₂ material used as the 3D substrates electrode can maximize the synergy between the CoSe₂ and NiSe₂, and also exhibits high efficiency of water splitting reaction. The lower overpotential of only 235 mV is presented to attain 20 mA cm⁻² compared to the benchmark of RuO₂ electrodes (270 mV @ 20 mA cm⁻²). Besides, the CoSe₂@NiSe₂ material also shows a remarkable improved hydrogen evolution reaction activity compared to NiSe₂ (192 mV@10 mA cm⁻²) and Co precursor catalysts (208 mV@10 mA cm⁻²) individually, which a low overpotential of only 162 mV is achieved at 10 mA cm⁻². The CoSe₂@NiSe₂ catalysts exhibit excellent water splitting performance (cell voltage of 1.50 V@ 10 mA cm⁻²) under alkaline conditions. It was proved that the high water splitting performance of the catalyst is attributed to high electrochemical activity area and synergistic effect. The work offers new ideas for the exploitation of synergistic catalysis of composite catalysts and adds new examples for the exploitation of efficient, better and relatively non-toxic electrocatalysts.     

Amorphous NiFe–OH/Ni–Cu–P supported on self-supporting expanded graphite sheet as efficient bifunctional electrocatalysts for overall water splitting

With the serious intensification of energy shortage and greenhouse effect, people begin to look for the sustainable energy sources to replace fossil energy sources. Herein, self-supporting expanded graphite sheet (SSEGS) was developed as an ideal catalyst support through electrochemically intercalating flexible graphite sheet in alkaline solution. Electroless deposition was employed to synthesize Ni–Cu–P alloy on SSEGS and then an amorphous NiFe hydroxide/Ni–Cu–P/SSEGS (NiFe–OH/Ni–Cu–P/SSEGS) composite catalyst was further constructed through electrodeposition. Benefitting from the unique structural advantage of SSEGS and the synergistic effect between two amorphous Ni-based materials (Ni–Cu–P alloy and NiFe–OH), the resulting electrode exhibited superior bifunctional electrocatalytic performance in 1 M KOH. For H₂ evolution reaction and O₂ evolution reaction, the NiFe–OH/Ni–Cu–P/SSEGS composite catalyst could reach 10 mA cm⁻² at low overpotentials of 75 and 240 mV, respectively. Remarkably, the two-electrode system driven by NiFe–OH/Ni–Cu–P/SSEGS as the anode and cathode could afford 10 mA cm⁻² at a low cell voltage of 1.56 V vs. RHE. And after the 12 h stability test, the cell voltage at 10 mA cm⁻² increased by only 7 mV, indicating that the two-electrode system had excellent stability. The preparation of NiFe–OH/Ni–Cu–P/SSEGS material with superior bifunctional electrocatalytic performance has a significance influence to the development and expansion of hydrogen production technology.     

Coupling NixSy-Ni2P heterostructure nanoarrays on Ni foam as environmentally friendly electrocatalyst for overall water splitting

The development of efficient, cheap and stable electrodes is the key to achieve the industrialization of hydrogen production from electrochemical water splitting. In this paper, Ni_xS_y-Ni₂P mixtures on Ni foam (Ni_xS_y-Ni₂P/NF) were synthesized by hydrothermal process followed by sulfurization and phosphorization approach. The combination of Ni_xS_y and Ni₂P exposes a large number of active sites, thus greatly improving the catalytic activity of the material. As expected, the Ni_xS_y-Ni₂P/NF material exhibits ultra-small overpotentials of 211 and 320 mV for water oxidation reaction at the current densities of 10 and 100 mA/cm², respectively. What is noteworthy is that the material also present superior hydrogen evolution reaction properties (122 mV@10 mA cm^?2). Moreover, when the material is acted as a bifunction electrode to drive the overall water splitting, only a cell voltage of 1.54 V is required to drive a current density of 10 mA/cm², which is one of the superior catalytic properties reported up to now. Experimental results show that the good electrochemistry performance of the Ni_xS_y-Ni₂P/NF material is attributed to the improved charge transfer rate, exposure of more active site and superior electrical conductivity. This work provides an effective way to explore environmentally friendly catalysts based on transition metal sulfide and phosphide.     

Super-hydrophilic/super-aerophobic Ni2P/Co(PO3)2 heterostructure for high-efficiency and durable hydrogen evolution electrocatalysis at large current density in alkaline fresh water,alkaline seawater and industrial wastewater

Seawater electrolysis has become an efficient method which makes full use of natural resources to produce hydrogen. However, it suffers high energy cost and chloride corrosion. Herein, we first present a Ni₂P/Co(PO₃)₂/NF heterostructure in which Co(PO₃)₂ with the nano-rose morphology in-situ grown on the rough Ni₂P/NF. The unique 3D nano-rose structure and the optimized electronic structure of the heterostructure enable Ni₂P/Co(PO₃)₂/NF super-hydrophilic and super-aerophobic characteristics, and highly facilitate hydrogen evolution reaction (HER) kinetics in alkaline fresh water, alkaline seawater and even industrial wastewater at large current density, which is rarely reported. Significantly, at large current densities, Ni₂P/Co(PO₃)₂/NF only requires overpotentials of 217 and 307 mV for HER to achieve 1000 mA cm⁻² in alkaline fresh water and alkaline seawater, respectively, and requires an overpotential of 469 mV for HER to deliver 500 mA cm⁻² in industrial wastewater. Furthermore, the overall seawater splitting system in the two-electrode electrolyzer only requires voltage of 1.98 V to drive 1000 mA cm⁻², which also demonstrates significant durability to keep 600 mA cm⁻² for at least 60 h. This study opens a new avenue of designing high efficiency electrocatalysts for hydrogen production at large current densities in alkaline seawater and industrial wastewater.     

Quick-to-synthesize hybrid electrodes composed of activated carbon cloth with Co/Fe-based films as bifunctional electrocatalysts for water splitting

Hybrid electrodes have recently been investigated as attractive alternatives to noble-metal-based electrocatalysts for hydrogen production by water splitting. Herein, we propose an electrode composed of an oxidized carbon cloth with an electrodeposited bimetallic Co/Fe-based film. By optimizing the electrodeposition conditions and applying electrochemically activated carbon cloth as a substrate, one can prepare a free-standing noble-metal-free electrocatalytic electrode with high bifunctional electrocatalytic activity in hydrogen and oxygen evolution from alkaline solution. The developed Fe_0.25Co_0.75 electrode requires overpotentials of 245 mV for HER and 360 mV for OER at high current densities of −100 and 100 mA cm⁻², respectively. Furthermore, its overall synthesis time from commercially available raw materials is only approximately 20 min. The electrode material was used as both a cathode and an anode in the model electrolyzer, which can deliver 10 mA cm⁻² of current density at 1.66 V without loss of activity during 100 h of performance.     

Engineering bimetallic cactus-like NiFeOOH/CoNiSe2 heterostructure nanosheets for efficient oxygen evolution and overall water splitting

The development of structural stable, high-performance, inexpensive electrocatalysts for oxygen evolution reactions (OER) is essential to alleviate the energy crisis. Herein, cactus-like CoNiSe₂ was synthesized on nickel foam and NiFeOOH was electrodeposited on surface of CoNiSe₂ to form a core-shell structural electrode. The obtained NiFeOOH/CoNiSe₂/NF exhibited ultra-low overpotentials of 204 mV and 234 mV at 10 and 100 mA cm⁻², with a Tafel slope of 26.2 mV dec⁻¹ in 1 M KOH alkaline solution. Furthermore, the current density only decreased by 5% after a 100 h durability test at 200 mA cm⁻², showing excellent robust stability. A two-electrode system with NiFeOOH/CoNiSe₂/NF as anode and Ni/NiO@MoO_3-x/NF as cathode (NiFeOOH/CoNiSe₂/NF||Ni/NiO@MoO_3-x/NF) showed a low voltage of 1.47/1.56 V to deliver 10/100 mA cm⁻². According to the experimental and density functional theory (DFT) results, the strong electronic interactions at the NiFeOOH/CoNiSe₂/NF interface leads to an increase in the valence state of Fe and an optimisation of the adsorption free energy, which are favourable to reduce the energy consumption of the OER. This work obtained high performance OER electrocatalysts by engineering amorphous and crystalline heterointerfaces and structural design, which will provide some inspiration for similar work.     

MoS2/NiFeS2 heterostructure as a highly efficient electrocatalyst for overall water splitting at high current densities

Searching for efficient, stable and low-cost nonprecious catalysts for oxygen and hydrogen evolution reactions (OER and HER) is highly desired in overall water splitting (OWS). Herein, presented is a nickel foam (NF)-supported MoS₂/NiFeS₂ heterostructure, as an efficient electrocatalyst for OER, HER and OWS. The MoS₂/NiFeS₂/NF catalyst achieves a 500 mA cm⁻² current density at a small overpotential of 303 mV for OER, and 228 mV for HER. Assembled as an electrolyzer for OWS, such a MoS₂/NiFeS₂/NF heterostructure catalyst shows a quite low cell voltage (≈1.79 V) at 500 mA cm⁻², which is among the best values of current non-noble metal electrocatalysts. Even at the extremely large current density of 1000 mA cm⁻², the MoS₂/NiFeS₂/NF catalyst presents low overpotentials of 314 and 253 mV for OER and HER, respectively. Furthermore, MoS₂/NiFeS₂/NF shows a ceaseless durability over 25 h with almost no change in the cell voltage. The superior catalytic activity and stability at large current densities (>500 mA cm⁻²) far exceed the benchmark RuO₂ and Pt/C catalysts. This work sheds a new light on the development of highly active and stable nonprecious electrocatalysts for industrial water electrolysis.     

In-situ growth of Fe–Co Prussian-blue-analog nanocages on Ni(OH)2/NF and the derivative electrocatalysts with hierarchical cage-on-sheet architectures for efficient water splitting

To design an efficient and cost-effective electrocatalyst based on Prussian blue and its analogs are a promising choice to realize energy transformation and storage via water-splitting. Herein, a facile and practical method is developed to in-situ grow Fe–Co Prussian-blue-analog (PBA) nanocages with an open hole in each face center on Ni(OH)₂/NF substrate to form the hierarchical cage-on-plate structure. Furthermore, the Fe–Co PBA nanocages attached to Ni(OH)₂/NF plates are hydrogenated and nitrogenized into FeCoNi/NF and FeCoNiN/NF electrodes, respectively. As-prepared electrodes successfully retain the 3D hierarchical micro-nano structures of Fe–Co PBA@Ni(OH)₂/NF precursor and can be used as a bifunctional water-splitting catalyst for overall water splitting. Compared to FeCoNi/NF, FeCoNiN/NF shows more efficiency and durability in the electrolytic water splitting tests in alkaline media. For the FeCoNiN/NF electrocatalyst, ultralow overpotentials for hydrogen evolution reaction (HER) are only 56 and 290 mV at current densities of 10 and 500 mA cm^?2. Meanwhile, overpotentials for oxygen evolution reaction (OER) are 267 and 374 mV at current densities of 50 and 500 mA cm^?2. The FeCoNiN/NF electrode can act both the cathode and the anode for overall water splitting, this electrolyzer only requires a cell voltage of 1.492 V to afford a current density of 10 mA cm^?2. This electrolyzer can stably deliver a viable high current density of 625 mA cm^?2 for 40 h to meet the condition of industrial application.     

Facile one-pot synthesis of binder-free nano/micro structured dendritic cobalt activated nickel sulfide: a highly efficient electrocatalyst for oxygen evolution reaction

Reasonable design and preparation of non-noble metal electrocatalysts with predominant catalytic activity and long-term stability for oxygen evolution reaction (OER) are essential for electrocatalytic water splitting. Ni foam (NF) is highlighted for its 3D porous structure, impressive conductivity and large specific surface area. Herein, nano/micro structured dendritic cobalt activated nickel sulfide grown on 3D porous NF (Co–Ni₃S₂/NF) has been successfully synthesized by one-step hydrothermal method. Due to the ingenious incorporation of Co, Co–Ni₃S₂/NF electrode shows auspicious electrocatalytic performance for OER compared with Ni₃S₂/NF electrode. As a result, Co–Ni₃S₂/NF needs overpotential of only 274 and 459 mV at current density of 10 and 50 mA cm⁻², respectively, while Ni₃S₂/NF requires overpotential of 344 and 511 mV. At potential of 2.0 V (vs. RHE), Co–Ni₃S₂/NF displays current density of 191 mA cm⁻², while Ni₃S₂/NF just attains current density of only 135 mA cm⁻². Moreover, Co–Ni₃S₂/NF demonstrates excellent stability for uninterrupted OER in alkaline electrolyte. The strategy of designing and preparing cobalt activated nickel sulfide grown on NF renders a magnificent prospect for the development of metal-sulfide-based oxygen evolution catalysts with excellent electrocatalytic performances.     

Ni3S2-MoSx nanorods grown on Ni foam as high-efficient electrocatalysts for overall water splitting

In order to solve the problem of large overpotential in water electrolysis for hydrogen production, transition metal sulfides are promising bifunctional electrocatalysts for hydrogen evolution reaction/oxygen evolution reaction that can significantly reduce overpotential. In this work, Ni₃S₂ and amorphous MoS_x nanorods directly grown on Ni foam (Ni₃S₂-MoS_x/NF) were prepared via one-step solvothermal process, which were used as a high-efficient electrocatalyst for overall water splitting. The Ni₃S₂-MoS_x/NF composite exhibits very low overpotentials of 65 and 312 mV to reach 10 mA cm⁻² and 50 mA cm⁻² in 1.0 M KOH for HER and OER, respectively. Besides, it exhibits a low Tafel slope (81 mV dec⁻¹ for HER, 103 mV dec⁻¹ for OER), high exchange current density (1.51 mA cm⁻² for HER, 0.26 mA cm⁻² for OER), and remarkable long-term cycle stability. This work provides new perspective for further the development of highly effective non-noble-metal materials in the energy field.     

In-situ construction of electrodeposited polyaniline/nickel-iron oxyhydroxide stabilized on nickel foam for efficient oxygen evolution reaction at high current densities

We report an in-situ construction method for the NiFe-based oxyhydroxide OER electrocatalyst supported on the nickel foam (NF) substrate with the polyaniline (PANI) interlayer by sequential electrochemical deposition steps (NF/PANI/NiFe–OH). The ultra-thin nanosheet for the nickel-iron (oxy)hydroxides tightly grown on the porous PANI exhibits the enhanced electrochemical characteristics associated with the promotion roles of the PANI layer, which increases the number of active sites, facilitates the charge transfer, and accelerates water transport across the interfaces of the electrode. The as-prepared NF/PANI/NiFe–OH has reliable lower overpotentials of 260, 340, and 490 mV without iR-correction at 50, 100, and 200 mA cm^?2 of high current densities, respectively. The smaller Tafel slope, larger ECSA, and TOF values of the electrode reveal its high intrinsic activity. Moreover, the electrode shows good stability and durability without the damage of morphology, change of surface chemical state, and substantial loss of active components at high current density.     

Boosting high-current water electrolysis: Superhydrophilic/superaerophobic nanosheet arrays of NiFe LDH with oxygen vacancies in situ grown on iron foam

Developing cost-effective and superior bifunctional electrocatalysts for alkaline water splitting is crucial to realizing hydrogen economy. However, in industrial applications, especially at high current densities, the sluggish kinetic process and the dissatisfactory prolonged stability of electrocatalysts astrict their applications. Herein, the superhydrophilic/superhydrophobic NiFe layered double hydroxide (LDH) with oxygen vacancies was designed in situ grown on iron foam (NiFe/IF) as a high-performance bifunctional electrocatalyst. The unique feature of the superhydrophilic/superaerophobic surface makes for electrolyte penetration and bubbles release, and the existence of oxygen vacancies grants the catalyst with enhanced inherent catalytic activity. Moreover, in situ Raman analysis reveals NiFe LDH could undergo surface reconstruction into active NiOOH species in the electrooxidation environment. Profiting from the above superiorities, the prepared NiFe/IF displays superior OER activity in 1 M KOH with low overpotentials of 245.2, and 480.2 mV to supply 100 and 1000 mA cm⁻², respectively. And the NiFe/IF exhibits prominent stability at 1000 mA cm⁻² under a simulated industrial condition (6 M KOH and 85 °C). Moreover, the water electrolysis device based on NiFe/IF as anode and cathode was assembled with a commercial solar cell to simulate a photovoltaic-driven water splitting system, which revealed a superior efficiency of 15.13% for solar hydrogen production.