Autologous growth of Fe-doped Ni(OH)2 nanosheets with low overpotential for oxygen evolution reaction

Highly active and durable electrocatalysts for oxygen evolution reaction (OER) play a vital role in water splitting. Despite numerous efforts, the strategies to prepare durable and effective electrocatalysts via scalable methods still remain a great challenge. In this work, we fabricated Fe-doped Ni(OH)₂ ultrathin nanosheets (Fe–Ni–OH/Ni) via autologous growing of Ni(OH)₂ from Ni foam, and in situ electrochemical-assisted doping Fe into Ni(OH)₂. Benefiting from the unique structure with large surface areas and strong coupling effects between Fe and Ni, the optimal Fe–Ni–OH electrodes exhibit remarkable catalytic performance toward OER, which requires an overpotential of 220 mV to achieve a current density of 10 mA cm⁻² with a Tafel slope of 48.3 mV dec⁻¹. The Fe–Ni–OH electrodes also possess high stability even under a high current density of 500 mA cm⁻² for 600 h with an ultralow overpotential of 290 mV. Using Ni–Fe–OH electrodes as both anode and cathode for overall water splitting, only a small overpotential of 1.57 V is required to reach a current density of 10 mA cm⁻². Moreover, the high catalytic performance and scalable preparation method can meet the emergency needs for the practical application.     

Autogenous growth of highly active bifunctional Ni–Fe2B nanosheet arrays toward efficient overall water splitting

Developing an effective and low-cost bifunctional electrocatalyst for both OER and HER to achieve overall water splitting is remaining a challenge to meet the needs of sustainable development. Herein, an electroless plating method was employed to autogenous growth of ultrathin Ni–Fe₂B nanosheet arrays on nickel foam (NF), in which the whole liquid phase reduction reaction took no more than 20 min and did not require any other treatments such as calcination. In 1.0 M KOH electrolyte, the resulted Ni–Fe₂B ultrathin nanosheet displayed a low overpotential of 250 mV for OER and 115 mV for HER to deliver a current density of 10 mA cm^?2, and both OER and HER activities remained stable after 26 h stability testing. Further, the couple electrodes composed of Ni–Fe₂B could afford a current density of 10 mA cm^?2 towards overall water splitting at a cell voltage of 1.64 V in 1.0 M KOH and along with excellent stability for 26 h. The outstanding electrocatalytic activities can be attributed to the synergistic effect of electron-coupling across Ni and Fe atoms and active sites exposed by large surface area. The effective combination of low cost and high electrocatalytic activity brings about a promising prospect for Ni–Fe₂B nanosheet arrays in the field of overall water splitting.     

Sprouts-like Fe(OH)2 hetero-nanostructures assembly on selenium layered nickel foam (NiF–Se) as an efficient and durable catalyst for electro-oxidation of urea

In this study, we develop selenium (Se)-iron hydroxide (NiF–Se@Fe(OH)₂) hetero-nanostructured catalyst system for fuel cell, and environmental-relevant urea-electro-oxidation reaction. For the rational engineering, the Se layers are initially deposited on the Ni foam substrate; then we grow Fe(OH)₂ hetero-nanostructures with various morphologies by introducing different ratios of Fe precursor sample. The Fe(OH)₂ ball-like nanorods to rock-like nanosheets are synthesized on the Se layered Ni foam surface by a simple hydrothermal process. The microscopic characterizations, and spectral analysis reveal the formation of Se integrated Fe(OH)₂ hetero-nanostructures such as ball-like nanorods, sprouts-like nanowire network, nanoflowers and rock-like nanosheets through effective Ni–O bond and Fe–Se bond for its typical synergism. The Se induces an interesting morphology transformation from crystalline nanorods to rock-like nanosheets structures that lead to the potential constituents for catalyst electrode that effectively merge the qualities such as high conductivity, large specific surface area, and larger catalytic active sites for electro-oxidation reaction of urea. Among them, NiF–Se@Fe(OH)₂ (8 mmol Fe(NO₃)₂) sprouts-like hetero-nanostructured network displays higher catalytic activity toward oxidation of urea (146.7 mA) with onset potential of 0.11 V vs. Ag/AgCl in 1 M NaOH + 0.1 M urea. Furthermore, the sprouts-like NiF–Se@Fe(OH)₂ nanowired network shows superior activity than the other aspect ratio's, excellent long-term stability, and reproducibility.     

Porous Ni2P nanoflower supported on nickel foam as an efficient three-dimensional electrode for urea electro-oxidation in alkaline medium

Porous Ni₂P nanoflower supported on nickel foam (Ni₂P@Ni foam) electrodes are synthesized via a simple hydrothermal growth strategy accompanied with further phosphating treatment. The prepared electrodes are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). Electro-catalytic performances towards urea electro-oxidation are tested by cyclic voltammetry (CV), chronoamperometry (CA) coupled with electrochemical impedance spectroscopy (EIS). By phosphating Ni(OH)₂ precursor, the final obtained Ni₂P@Ni foam electrode presents a porous Ni₂P nanoflower structure within abundant porosity, and so exposes a large amount of electro-catalytic active sites and electronic transmission channels to accelerate the interfacial reaction. Compared with Ni(OH)₂@Ni foam precursor, the Ni₂P@Ni foam catalyst exhibits more excellent electro-catalytic activity as well as lower onset oxidation potential. Remarkably, the Ni₂P@Ni foam catalyst reaches a peak current density of 750 mA cm^?2 with an onset oxidation potential of 0.24 V (vs. Ag/AgCl) accompanied by an excellent stability in 0.60 M urea with 5.00 M KOH solutions. Benefiting from the unique porous nanosheet structure, the as-synthesized Ni₂P@Ni foam catalyst performs a highly enhanced catalytic behavior for alkaline urea electro-oxidation, indicating that the material can be hopefully applied in direct urea fuel cells.     

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.     

In-situ self-reconstruction of Ni–Fe–Al hybrid phosphides nanosheet arrays enables efficient oxygen evolution in alkaline

Developing efficient oxygen evolution reaction (OER) electrocatalysts with earth-abundant elements is very important for sustainable H₂ generation via electrochemical water splitting. Here we design a crystalline-amorphous Ni–Fe–Al hybrid phosphides nanosheet arrays grown on NiFe foam for efficient OER application. Dynamic surface reorganization of phosphides at anodic/cathodic polarizations is probed by in situ Raman spectroscopy. The reconstructed amorphous Ni(Fe)OOH species are determined as the active phases that facilitate the OER process. This unique electrode shows highly catalytic activity toward water oxidation, achieving the current densities of 10 and 100 mA cm^?2 at 181 and 214 mV in 1 M KOH, respectively. Meanwhile, it also exhibits excellent stability at a large current density of 100 mA cm^?2 for over 60 h. This work reveals the dynamic structural transformation of pre-catalyst in realistic conditions and highlights the important role of oxyhydroxides as real reactive species in OER process with high activity.     

One-step synthesis of atomic Ru doped ultra-thin Co(OH)2 nanosheets for oxygen evolution reaction in different pH values

Herein, atomic Ru doped ultra-thin Co(OH)₂ nanosheet arrays are firstly synthesized by a one-step electrochemical deposition method. Importantly, the obtained electrocatalyst can display excellent activity for oxygen evolution reaction, which only needs 305 mV at 50 mA cm^?2 in 1 M KOH and 261 mV at 10 mA cm^?2 in 0.1 M KOH. Further mechanism studies disclose that the doping of Ru could reduce the thickness of nanosheets and contribute to the generation of active Co³⁺ sites by donating electrons from Co to Ru atoms via the Co–O–Ru bonds. This work paves a simple method to fabricate Co based nanosheet catalyst, which may be extended to the preparation of other highly active electrocatalysts.     

Nickel hydroxide armour promoted CoP nanowires for alkaline hydrogen evolution at large current density

The development of hydrogen evolution activity (HER) electrocatalyst that can run durably and efficiently under the large current density is of special significance but still challengeable for the massive production of hydrogen. Herein, a CoP/Ni(OH)₂ nanowire catalysts grown on Co foam (CF) with a three-dimensional heterojunction structure has been successfully prepared by electrodepositing nickel hydroxide on the surface of cobalt phosphide. The prepared CoP/Ni(OH)₂–15 min sample reveals a superior HER activity and stability. It merely requires ultralow overpotentials of 108 and 175 mV to 100 and 500 mA cm^?2, respectively. In addition, the long-term stability test shows that the catalyst (CoP/Ni(OH)₂–15 min) can operate stably for at least 70 h at 400 mA cm^?2. Utilizing NiFe-LDH/IF with high OER activity, the NiFe-LDH/IF || CoP/Ni(OH)₂–15 min catalyst system possesses the same outstanding performance for overall water splitting (OWS), which can accomplish ≈ 500 mA cm^?2 at 1.74 V in 1 M KOH electrolyte. Moreover, the NiFe-LDH/IF || CoP/Ni(OH)₂–15 min couple can work for more than 80 h at 500 mA cm^?2, indicating its a great prospect in the area of electrolysis water. Such excellent catalytic performance is mainly attributed to the armor effect of Ni(OH)₂, which can not only promote the rapid decomposition of water molecules, but also prevent the loss of phosphorus and enhance the synergistic effect of CoP and Ni(OH)₂. This work can offer a significant reference for the design with high-performance and durable transition metal phosphide electrocatalysts.     

Controllable transformation of sheet-like CoMo-hydro(oxide) and phosphide arrays on nickel foam as efficient catalysts for alkali water splitting and Zn–H2O cell

Design and synthesis of cost-effective electrocatalysts with remarkable activity and stability is highly desirable for renewable energy devices. Herein, we have successfully constructed sheet-like CoMoO₄–Co(OH)₂ and CoMoP–CoP arrays on nickel foam (NF) through chemical etching ZIF-67 arrays and phosphorization in sequence. Series CoMoO₄–Co(OH)₂/NF as anode and CoMoP–CoP/NF as cathode showed excellent electrocatalytic activity and stability in alkali water splitting, where the combined catalysts only need 1.67 V cell voltage to drive 10 mA cm^?2 and obtain robust high current stability at 500 mA cm^?2 for 110 h with almost no attenuation. In addition, using CoMoP–CoP/NF as the cathode of a Zn–H₂O cell can provide a power density of 11.5 mW cm^?2 and a stable 170 h for simultaneous H₂ and electricity generation. The excellent performance of the system is attributed to the unique sheet-like array morphology of combined catalysts providing large surface area and rich pore structure conducive to electrolyte diffusion and gas emission, as well as the synergies between the different components providing more catalytic active sites.     

Improved electrocatalytic kinetics of nickel hydroxide nanoparticles on Vulcan XC-72R carbon black towards alkaline urea oxidation reaction

Nickel hydroxide nanoparticles were fabricated on Vulcan XC-72R carbon black using various reducing agents through assisted microwave polyol process. The formed electrocatalysts using sodium borohydride [Ni(OH)₂/C–NB], ethylene glycol [Ni(OH)₂/C–EG] and a mixture of them [Ni(OH)₂/C–EGNB] displayed an electrocatalytic activity towards urea oxidation in NaOH solution. The oxidation peak potential and current density values were greatly influenced by the employed reducing agent. Lower onset and peak potential values were measured at Ni(OH)₂/C–EGNB, while Ni(OH)₂/C–EG exhibited the highest oxidation current density during urea oxidation reaction. Electroactive surface area measurements revealed that the number of available active sites for the oxidation reaction was arranged in an ascending order as Ni(OH)₂/C–NB < Ni(OH)₂/C–EGNB < Ni(OH)₂/C–EG. The diffusion coefficient of urea molecules at Ni(OH)₂/C–EG and Ni(OH)₂/C–EGNB was 14.69 and 5.90 times higher than that at Ni(OH)₂/C–NB. Stable performance was measured at all studied electrocatalysts over prolonged operation suggesting their valuable application as efficient anode materials in direct urea oxidation fuel cells.     

Construction of Co(OH)F/Ni(OH)2@Fe(OH)3 core-shell heterojunction on nickel foam for efficient oxygen evolution

The sluggish anodic reaction (OER) kinetics hinder electrochemical water splitting at high energy densities, which can be solved by developing suitable catalysts. Herein, we report a novel Co(OH)F/Ni(OH)₂@Fe(OH)₃-D_x (D_x represents the hydrolysis time, X = 0.5, 1, 2 days) heterojunction grown on nickel foam, which was synthesized by the hydrolysis of Fe³⁺ on the Co(OH)F/Ni(OH)₂ surface at room temperature. Electrocatalytic oxygen evolution tests showed that the prepared Co(OH)F/Ni(OH)₂@Fe(OH)₃-D_x composites had better catalytic activity than pure Co(OH)F/Ni(OH)₂ in 1.0 M KOH, especially Co(OH)F/Ni(OH)₂@Fe(OH)₃-D₁. It only requires an ultra-low overpotential (η₁₀) of 270 mV, SEM and TEM showed that Co(OH)F/Ni(OH)₂@Fe(OH)₃-D₁ is a perfect all-encapsulated core-shell structure, which facilitates the exposure of active sites and electron transfer, and thus obviously improves oxygen evolution.     

Facile in-situ electrochemical fabrication of highly efficient nickel hydroxide-iron hydroxide/graphene hybrid for oxygen evolution reaction

Oxygen evolution reaction (OER) is an essential process in energy conversion and storage, especially in water electrolysis, while developing active and low-cost catalysts is the key to maximizing O₂ production. Here a facile three-electrode electrolysis system is firstly applied to synthesize nickel hydroxide-iron hydroxide/graphene hybrid. To fully utilize the electrical energy and simplify the catalyst synthesis, we made graphite exfoliated into graphene at the cathode and nickel-iron hydroxide synthesized at the anode simultaneously. The best electrocatalytic performance of Ni–Fe/G for OER shows an overpotential of 280 mV (without iR compensation) at 10 mA cm^?2, superior to commercial RuO₂ (341 mV). Results show that the introduction of Fe in Ni–Fe/G not only converts part of α-Ni(OH)₂ into more active β-Ni(OH)₂, but promotes the electric conductivity and electrochemically active surface area (ECSA) of the obtained Ni–Fe/G, therefore Ni–Fe/G shows the superior OER performance. The OER activity of Ni–Fe/G can be further adjusted by experiment conditions including electrolysis time and electrolyte concentration. This work provides a novel and facile method for highly efficient OER via engineering the non-noble metal hydroxide/graphene hybrid.     

Direct synthesis of binder-free Ni–Fe–S on Ni foam as superior electrocatalysts for hydrogen evolution reaction

Designing the efficient, low-cost and stable electrocatalyst is of great significance for storage and conversion of the renewable energy to hydrogen. Herein, the binder-free Ni–Fe–S electrocatalysts were directly electrodeposited on Ni foam, which exhibited the excellent hydrogen evolution reaction performance with the overpotential of 51.4 mV at the current density of 10 mA cm^?2. Based on the analysis and results of as-synthesized Ni, Ni–Fe and Ni–S, the boosted electrocatalytic activity can be attributed to the composite effect between Ni and the introduced Fe and S. Additionally, the Ni–Fe–S electrocatalysts also displayed the low cell voltage (1.59 V at 10 mA cm^?2), remarkable durability and high Faraday efficiency in overall water electrocatalysis. Moreover, the water electrolysis device with Ni–Fe–S bi-electrodes can be driven by a small wind power generation and producing 4 mL H₂ in 39 min, indicating the prepared Ni–Fe–S electrocatalyst has the great potentials in producing hydrogen via renewable energy.     

Effect of graphene on the performance of nickel foam-based CoNi nanosheet anode catalyzed direct urea-hydrogen peroxide fuel cell

The highly porous electrode of a crisscrossed CoNi nanosheets array grown on reduced graphene oxide decorated Ni foam (CoNi/rGO@Ni foam) is fabricated through a facile dip and dry method followed by electroreduction and electrodeposition methods. The phase composition and morphology of the electrode are characterized by XRD, SEM, TEM, and EDS. In single electrode tests, CoNi/rGO@Ni foam electrode displays an excellent catalytic performance (330 mA cm⁻² at 0.6 V) and stability towards urea electrooxidation when comparing to Ni foam and CoNi nanosheets modified Ni foam (CoNi@Ni foam) electrode. Besides, a low initial oxidation potential of urea electro-oxidation to 0.14 V is achieved on the CoNi/rGO@Ni foam electrode. The introducing of rGO to the electrode greatly reduced the reaction activation energy from 14.47 to 10.35 kJ mol⁻¹. Besides, large active surface area (261.67 cm²) is also obtained from the electrode. The CoNi/rGO@Ni foam anode exhibits a maximum power density of 12.58 mW cm⁻² in direct urea-hydrogen peroxide fuel cell tests. Excellent performance shows in single electrode tests and fuel cell tests suggest that addition of rGO to the electrode is an easy and feasible method to enhance the performance of the catalyst.     

Efficient and stable Ni–Co–Fe–P nanosheet arrays on Ni foam for alkaline and neutral hydrogen evolution

The development of highly efficient and superior durability electrocatalysts is vital to expedite hydrogen evolution reaction (HER). Herein, a mixed amorphous and nano-crystalline Ni–Co–Fe–P alloy on Ni foam after 75 s dealloying in 3 M HCl (Ni–Co–Fe–P/NF-3-75) is synthesized by the preparation strategy of two-step method consisting of electroless deposition and dealloying process. Ni–Co–Fe–P/NF-3-75 shows an excellent HER performance and high durability in both alkaline and neutral conditions by optimizing the composition of the catalysts, acid concentration, and the time of dealloying. Benefitting from the high conductivity of Ni foam carrier, coordination between polymetallic phases, and the large exposure of defects, the as-prepared Ni–Co–Fe–P/NF-3-75 requires only a low overpotential of 56 mV and 104 mV to reach the current density of 10 mA cm⁻² in 1.0 M KOH and 1.0 M phosphate buffer (PBS), respectively. Remarkably, the Ni–Co–Fe–P/NF-3-75 electrode exhibits superior cycling stability and long-term robust durability without obvious overpotential decline. The successful preparation of the Ni–Co–Fe–P/NF-3-75 catalyst indicates that this method provides an efficient way to synthesize polymetallic phosphides for hydrogen evolution reaction.     

Grain boundaries of Co(OH)2-Ni-Cu nanosheets on the cotton fabric substrate for stable and efficient electro-oxidation of hydrazine

Metal/metal hydroxide hybrid heterostructures exhibits superior performances in diverse research fields, especially in catalysis due to the presence of ample grain boundary interfaces and the strong metal/metal hydroxide synergistic actions. Herein, Co(OH)₂-Ni hybrid heterostructures with a crystalline Ni and Co(OH)₂ is prepared on the cotton fabric substrate by a simple electrochemical process. The Co(OH)₂-Ni hybrid heterostructures are explored as a highly active catalyst for the electro-oxidation of hydrazine in an alkaline medium. The existence of ample grain boundary interfaces and promotional synergistic effect between the nanocrystalline metallic Ni and Co hybrid heterostructures lead to a very low-onset hydrazine oxidation potential of −0.06 V vs RHE. Moreover, the Co(OH)₂-Ni hybrid heterostructured electrode exhibits excellent long-term catalytic stability.     

Facile synthesis of carbon nanosheet arrays decorated with chromium-doped Co nanoparticles as advanced bifunctional catalysts for Zn-air batteries

The development of low-cost electrochemical catalytic nanomaterials for efficient oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) through structural and composition control is a great challenge. Herein, a 3D hybrid structure is designed by an in-situ approach for growing 2D leaf-like nanosheet arrays on 1D electrospun nanofibers. The resultant catalysts composed of Cr-doped Co nanoparticle decorated N-doped carbon nanosheet and carbon nanofiber are synthesized by subsequent Cr³⁺ impregnation and heat treatment. The excellent properties of the as-prepared cathode benefit from the novel establishment of the 3D structure and the regulating mechanism of the electron density of Co after Cr doping, which simultaneously increases the mass and charge transfer process during the catalytic reaction. Consequently, Cr_0.10-Co@NC exhibits excellent catalytic performance for the ORR (with a half-wave potential of 0.84 V) and OER (with an overpotential of 370 mV). When used in a homemade ZAB for evaluating their practical reversible performance, the device exhibits a higher open-circuit voltage (1.45 V) and a smaller potential gap (0.73 V) with excellent cycle durability of 110 h. This work offers a well-designed structure and development for synthesizing efficient and durable electrocatalysts in electrochemical energy conversion technologies.     

Vermicular Ni3S2–Ni(OH)2 heterostructure supported on nickel foam as efficient electrocatalyst for hydrogen evolution reaction in alkaline solution

Alkaline solution is considered to be more suitable for industrial application of hydrogen production by water electrolysis. However, most of the low-cost electrocatalyts such as Ni₃S₂ has poor ability to dissociate HO–H, resulting in unsatisfied hydrogen evolution performance in alkaline media. In this paper, a novel vermicular structure of Ni₃S₂–Ni(OH)₂ hybrid have been successfully prepared on nickel foam substrate (v-Ni₃S₂–Ni(OH)₂/NF) through a facile two-step containing hydrothermal and electrodeposition processes. The heterostructure consists of rod-like Ni₃S₂ and Ni(OH)₂ nanosheets, in which Ni(OH)₂ is coated on the surface of Ni₃S₂. This structure not only constructs a fast electron transfer channel but also possesses rich heterointerface, thus accelerating the Volmer step and allowing more active sites of Ni₃S₂ to functioning well. As a result, v-Ni₃S₂–Ni(OH)₂/NF exhibited excellent electrocatalytic activity toward HER in 1.0 M KOH solution. It only needs 78 mV and 137 mV to drive current density of 10 mA cm⁻² and 100 mA cm⁻². Moreover, the catalytic stability of this electrocatalyst in alkaline solution is also satisfactory.     

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.     

Three-dimensional copper cobalt hydroxide electrode for anion exchange membrane water electrolyzer

Anion exchange membrane (AEM) water electrolyzers are promising energy devices for producing low-cost and clean hydrogen using platinum group metals (PGMs). However, AEM water electrolyzers still do not show satisfactory performance due to the sluggish kinetics of the electrodes. In this work, copper cobalt hydroxide (CuCo-hydroxide) nanosheet was synthesized on commercial nickel foam (NF) via electrochemical co-precipitation, and used directly as an oxygen evolution reaction (OER) electrode for an AEM electrolyzer. The interaction between Cu and Co induces a change in the electronic structure of Co(OH)₂ and improves the performance of the OER electrode. In addition, the AEM electrolyzers catalyzed by CuCo(OH)₂ showed high energy conversion efficiency of 73.5%. This work demonstrates that non-PGM based electrodes fabricated using a simple electrochemical co-precipitation apply to AEM electrolyzers for low-cost and clean hydrogen production.