Efficient Bifunctional Electrodes Research Articles

Controlled synthesis of Sn doped Cu–Ni3S2 on Ni foam as efficient electrocatalyst for urea oxidation reaction and oxygen evolution reaction

Hydrogen production technology by urea-assisted electrocatalytic water decomposition has become one of the important means to alleviate carbon emissions and water pollution. In this paper, we first doped Sn and Cu element into the Ni3S2 material by hydrothermal method on the Ni foam support. This Cu–Sn–Ni3S2 material exhibits superior urea (potential of 1.42 V at 100 mA cm−2) and water oxidation (potential of 1.63 V at 100 mA cm−2) properties, which is one of the best electrochemical performance reported up to now. Analysis of experiment demonstrate that the increase in catalytic performance is assigned to faster charge transfer, more exposure of reaction centres and smaller resistance owing to doping of Sn and Cu. Density functional theory (DFT) analysis demonstrates that introduction of Sn and Cu increases the adsorption energy of urea and improves the conductivity of the Cu–Sn–Ni3S2 material, and the co-doping of the two changes the electron state density of the active site, thereby promoting the catalytic performance. This work provides insights into the development of efficient bifunctional electrodes for urea oxidation and oxygen evolution reaction through doping strategies.

Interfacial electronic modulation of NiCo decorated nano-flowered MoS2 on carbonized wood as a remarkable bifunctional electrocatalyst for boosting overall water splitting

The development of a cost-effective and efficient bifunctional electrode for overall water splitting holds significant importance in accelerating the sustainable advancement of hydrogen energy. The present study involved a bifunctional catalytic electrode was prepared by loading NiCo-modified 1T/2H MoS2 onto carbonized wood (NiCo-MoS2-CW) using the hydrothermal and electrodeposition techniques. The XPS analysis revealed that NiCo-modified MoS2 exhibited a weak electron characteristic, which facilitated the ionization of H2O and significantly enhanced the Volmer step. The XPS analysis unveiled that NiCo-modified MoS2 displayed a weak electron characteristic, thereby promoting the ionization of H2O and substantially augmenting the Volmer step. The electrocatalytic performance of the NiCo-MoS2-CW in 1.0 M KOH is remarkably impressive, exhibiting minimal overpotentials of only 64 mV (10 mA cm−2) and 216 mV (50 mA cm−2) for the hydrogen evolution reaction and oxygen evolution reaction, respectively. The NiCo-MoS2-CW || NiCo-MoS2-CW electrolytic cell can achieve a cell voltage of only 1.69 V to achieve a current density of 50 mA cm−2. Overall, this study proposes a potential approach to improve the catalytic efficiency of overall water splitting by modulating the interfacial electronic properties of MoS2.

Superhydrophilic 3D amorphous/crystalline heterostructure: Nanosheets-assembled CoMoP-FexP/NF as efficient bifunctional electrodes for alkaline water splitting

To push forward the hydrogen energy technology, it is crucial to develop a highly active catalyst for the application of water splitting. Nevertheless, many electrocatalysts suffer from functional limitations, making them unsuitable for both anode and cathode applications. Therefore, the utilization of bifunctional electrocatalysts is necessary to overcome this limitation. In this study, we have reported a bifunctional CoMoP-FexP/NF catalyst with favorable electrocatalytic performance toward hydrogen evolution reaction/oxygen evolution reaction (HER/OER). Balanced amorphous/crystalline heterophase endows CoMoP-FexP/NF with more exposed active sites. In addition, the superhydrophobic nature of CoMoP-FexP/NF helps to improve the contact with electrolyte. Following conditional optimization, CoMoP-FexP/NF requires only an overpotential of 85.6 mV to achieve a current density of 10 mA cm−2 for HER, and 249.6 mV for a current density of 20 mA cm−2 for OER. A water-splitting electrolyzer comprising CoMoP-FexP/NF requires a low cell voltage of 1.56 V to achieve a current density of 10 mA cm−2. This study provides valuable insights into designing bifunctional electrocatalysts and replacing noble metallic materials to enhance hydrogen production from water splitting.

Iron-doping-induced formation of Ni-Co-O nanotubes as efficient bifunctional electrodes.

The rational design of earth-abundant and efficient electrocatalysts to replace precious metal-based materials is highly anticipated for overall water splitting. Herein, NiCo2O4 electrocatalysts with different Fe doping amounts (Fex-NCO, x = 1, 2, 3) were synthesized by a low-temperature chemical method. It was interesting to find that the doping of Fe induced the formation of NiCo2O4 nanotube arrays by modulating the Fe content. The Fe3-NCO electrode with a nanotube structure and rich oxygen vacancies exhibited exceptional electrocatalytic activities for the hydrogen evolution reaction (97 mV, 10 mA cm-2) and oxygen evolution reaction (188.4 mV, 10 mA cm-2). DFT calculations revealed that Fe promoted the modulation of the electronic structure, which played a crucial role in optimizing the reaction intermediates and altered the energy level of the d band center, and as a result, enhanced the water dissociation ability. Additionally, a low cell voltage of 1.56 V (10 mA cm-2) was realized for water splitting based on an as-fabricated Fe-doped NiCo2O4 nanotube array bifunctional electrode.

Carbon nanofibers implanted porous catalytic metal oxide design as efficient bifunctional electrode host material for lithium-sulfur battery

The shuttling effect of lithium polysulfides (LiPSs) and uncontrolled dendrite formation of metal lithium anode are the two critical obstacles hindering the commercial application of lithium-sulfur (Li-S) batteries. Herein, a bifunctional electrode host design consists of carbon nanofibers implanted ordered porous Co-decorated Al2O3 supported on carbon nanotube film (CNTF) is proposed to address these problems. As cathode sulfur host material, benefiting from the synergistic effect of porous Co-Al2O3 and the embedded CNFs, the CNFs/Co-Al2O3@CNTF exhibits excellent conductivity, efficient LiPSs confinement and catalytic conversion performance. It shows a high initial capacity of 1165 mAh g−1 at 0.2 C, and holds a capacity of 594 mAh g−1 even up to 3 C. When serves as anode, the CNFs/Co-Al2O3@CNTF electrode exhibits excellent Li+ diffusion performance and uniform lithium growth behavior, achieving a dendrite-free lithium electrode. The anode also shows good cycle stability during an ultra-long cycle time of 1000 h. A flexible pack cell assembled from CNFs/Co-Al2O3@CNTF electrodes delivers a specific capacity of 972 mAh g−1 with capacity retention rate of 86.4% at 0.1 C.

Recycled Steel from Waste Dead Nickel–Metal Hydride (Ni–MH) Batteries as Efficient Bifunctional Electrodes for Water Splitting: Ideal Way from Waste to Energy

Recycled Steel from Waste Dead Nickel–Metal Hydride (Ni–MH) Batteries as Efficient Bifunctional Electrodes for Water Splitting: Ideal Way from Waste to Energy

Carbon fiber cloth loaded core-shell structured Pd@AgCl-Ag as an efficient bifunctional electrode for direct hydrogen peroxide-hydrogen peroxide fuel cells

A bifunctional Pd@AgCl-Ag/O-CFC electrode was prepared on oxidized carbon fiber cloth (O-CFC) by hydrothermal method and Galvanic reaction and used for catalytic H2O2 reduction reaction (HPRR) and oxidation reaction (HPOR). The catalyst on electrode surface presents a particular core-shell structure with Ag and AgCl as the core and Pd and AgCl as the shell, facilitating the synergistic interaction between the bimetals and the exposure of the primary active substance of Pd. The Pd@AgCl-Ag/O-CFC electrode exhibited excellent catalytic performance for both HPRR and HPOR with current densities of − 733.3 mA cm−2 and 708.0 mA cm−2, respectively. For the kinetic study, the activation energy of HPRR catalyzed by the Pd@AgCl-Ag/O-CFC electrode was low (7.59 kJ mol−1), and both the electroreduction and electrooxidation reaction processes were controlled by a hybrid of substance diffusion and kinetics. The electroreduction and electrooxidation reactions of H2O2 on the surface of the Pd@AgCl-Ag/O-CFC electrode are both irreversible processes, and their reaction levels are 1 and 0.5, respectively. The direct hydrogen peroxide-hydrogen peroxide fuel cell (DPPFC) was assembled with Pd@AgCl-Ag/O-CFC as a bifunctional electrode, and the open circuit potential reached 0.75 V and power density reached 61.9 mW cm−2 at 338.15 K. In addition, due to the stability of the structure and catalytic performance of the Pd@AgCl-Ag/O-CFC electrode, the DPPFC can operate stably for a long time. This work indicates that the as-prepared Pd@AgCl-Ag/O-CFC can be a promising electrode for DPPFC.

Enhanced electrocatalytic performance of electrodeposited NiCu alloy as an efficient Bi-functional electrode by prolonged potentiostatic activation

The challenges in electrocatalytic water splitting are to develop a bifunctional catalyst and the role of fabricating catalyst is for commercialization purposes. For that, a simple electrodeposition technique can be used to fabricate the electrode. In this work, the NiCu electrocatalyst was fabricated using a simple electrodeposition technique in which a highly stable binder-free electrode was deposited. The fabricated films were deposited at different current densities and deposition temperatures to improve the efficiency of the electrode for water splitting. The fabricated electrode shows an excellent oxygen evolution reaction (OER) and Hydrogen evolution reaction (HER). Then the sample is subjected to the electrocatalytic Oxygen Evolution Reaction (OER) and Hydrogen Evolution Reaction (HER) studies in 1 M KOH which shows excellent activity. The film prepared at 15 A/cm2 shows outstanding OER and HER than the samples prepared at the current density of 5 A/cm2, 10 A/cm2, 15 A/cm2 @50 °C and 15 A/cm2@70 °C. The film prepared at 15 A/cm2 shows an overpotential of 310 mV@ 10 mA for OER and 131 mV@10 mA for HER with Tafel values of about 40 mV/dec and 94 mV/dec respectively. The charge transfer kinetics of the prepared catalyst was analysed using the Tafel slope, and lower Tafel slopes were observed for 15 A/cm2 which was lower than other catalysts. To check the stability of the fabricated film, a prolonged PSTAT analysis was carried out for 12 h. After the PSTAT analysis, an increase in the activity of the sample was observed. This is due to prolonged activation of the surface which enhances the activity of the OER and HER. The larger shift in the overpotential toward cathodic and anodic is due to the PSTAT activation which activates the catalyst and results in a compressive strain of about 6.085 % expansion in the lattice significantly enhancing the activity. The film prepared at 15 A/cm2 shows an overpotential of 280 mV@ 10 mA for OER and 65 mV@10 mA for HER. A shift of about 66 mV in HER and a shift of about 30 mV in OER was observed. Prolonged activation results in the increased activity show that the catalyst can be used as an alternate electrode for future application.

Substrate self-derived porous rod-like NiS/Ni9S8/NF heterostructures as efficient bifunctional electrocatalysts for overall water splitting.

A self-derivation strategy using conductive substrates is used to prepare one-piece highly efficient bifunctional electrodes, where the chosen substrate acts as both an active catalyst precursor and a conductive carrier. Here, a bifunctional catalyst, porous NiS/Ni9S8/NF-2 nanorods, was synthesized by low-temperature vulcanization after an oxalic acid etching process. To reach a current density of 10 mA cm-2, NiS/Ni9S8/NF-2 requires only a tiny overpotential of 115 mV for the HER and 176 mV for the OER, and demonstrates sustained activity for 100 hours with almost any degradation. The substrate self-derived NiS/Ni9S8/NF-2 catalyst for overall water splitting requires only a small voltage of 1.52 V to deliver 10 mA cm-2 with excellent stability. Experimental results show that the heterostructured electrocatalysts impart good catalytic properties of NiS/Ni9S8/NF-2 by modulating the electronic structure and promoting the reconstruction process from sulfides to hydroxides. This work demonstrates the success of the substrate self-derivation strategy to achieve high catalytic activity and provide a new autogenous growth technique for electrode fabrication.

Green and sustainable bifunctional carbonized wood electrodes decorated with controlled nickel/α(β)-nickel(ii) hydroxide to boost overall water splitting

For highly efficient bifunctional electrodes, flower-shaped Ni/α-Ni(OH)2 particles and nanosheet-shaped Ni/α&β-Ni(OH)2 arrays are in situ grown on 3D carbonized wood to accelerate mass transfer and release generated bubbles during overall water splitting.

A Highly Efficient and Robust Bifunctional Perovskite‐Type Air Electrode with Triple‐Conducting Behavior for Low‐Temperature Solid Oxide Fuel Cells

AbstractCobalt‐rich materials have generally been recognized as the prevailing candidates of cathodes for low‐temperature solid oxide fuel cells (LT‐SOFCs, 400–600 °C). Regrettably, their instability and high cost are the major concerns for future commercialization. In response to these drawbacks, here, an A‐site‐deficient low‐cobalt‐containing perovskite‐type oxide, Ba0.95Fe0.7Co0.2Sc0.1O3‐δ (BFCS0.95), as an efficient bifunctional electrode with triple‐conducting (H+|O2−|e−) nature for oxygen‐ion conducting SOFCs (O‐SOFCs) and proton conducting SOFCs (H‐SOFCs) is proposed. BFCS0.95 electrode exhibits impressive versatility in catalyzing oxygen reduction reaction, i.e., ultralow area‐specific resistances (0.072 Ω cm2 for O‐SOFCs and 0.4 Ω cm2 for H‐SOFCs at 550 °C, respectively), extraordinarily high power outputs (1092 mW cm−2 for O‐SOFCs and 419 mW cm−2 for H‐SOFCs at 550 °C, respectively), excellent long‐term durability (>100 h for O‐SOFCs and H‐SOFCs at 600 °C), remarkable reversibility between pure air and CO2‐containing air, and superior resistance against temperature fluctuations. The combined experimental and computational studies elucidate the roles of A‐site deficient state and triple‐conducting behavior, both of which are essential to overall electrochemical performance. Low‐cobalt‐containing feature also makes BFCS0.95 cathode economically competitive among all cobalt‐containing analogues. Overall, the finding paves a highly efficient route to develop bifunctional electrodes for LT‐SOFCs toward a sustainable energy future.

Controlled synthesis of Fe doped NiCoM (M=O, P, S and Se) as robust electrocatalyst for urea electrolysis

Electrochemistry urea electrolysis method is more significant in practical application and cost saving than water splitting technology for production of hydrogen. In this work, a series of Fe doped NiCoM (M=O, P, S and Se) materials with unique structure of nanosheet and nanoneedle were successfully synthesized on Ni foam by typical hydrothermal and annealing processes. What is noteworthy is that Fe-NiCoP, as an efficient bifunctional electrode, presents superior electrochemistry activity for urea oxidation reaction (UOR) and hydrogen evolution reaction (HER) with requiring a potential of 1.369 V at 100 mA cm−2 and overpotential of 150 mV at 10 mA cm−2. In the process of electrolysis of urea, the Fe-NiCoP//Fe-NiCoP electrode couple display superior electrochemical performance (cell voltage of 1.50 V @ 10 mA cm−2). The enhanced electrocatalytic activity of Fe-NiCoP electrodes was attributed to improved reaction kinetics by Ni12P5 and increased conductivity by Fe-Co2P, resulting in rapid electron transfer, increased active site exposure and good conductivity. Density functional theory calculations show that the Ni12P5 material exhibits a small Gibbs free energy for hydrogen adsorption and plays a major role in hydrogen production. This work provides a novel idea for the research and exploitation of low cost and robust UOR and HER electrocatalysts.

A Highly Efficient Bifunctional Electrode Fashioned with In Situ Exsolved NiFe Alloys for Reversible Solid Oxide Cells

A Highly Efficient Bifunctional Electrode Fashioned with In Situ Exsolved NiFe Alloys for Reversible Solid Oxide Cells

One-step synthesis of mesoporous Cobalt sulfides (CoSx) on the metal substrate as an efficient bifunctional electrode for overall water splitting

Electrocatalysts based on transition metal sulfides (TMSs) are drawing accelerating concerns in renewable energy research because of their intrinsically excellent activities towards both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). To date, considerable efforts are made to improve the performance of these catalysts, but ignoring the improper synthesis strategy would incur additional cost to the catalyst. Herein, a convenient, one-step anodization method is developed for fast construction of cobalt sulfides (CoSx). Without any high-temperature or long-time treatment, mesoporous CoSx is self-grown on the metal substrate in minutes. As a result, as-anodic CoSx requires overpotentials of 102 mV for HER and 284 mV for OER to achieve a current density of 10 mA m−2 in alkaline solution. Moreover, the tandem bifunctional as-anodic CoSx exhibits a required cell voltage of 1.64 V for overall water splitting in alkaline solution, exceeding most of the documented Co-based electrocatalysts.

Metal-organic frameworks-derived CoP anchored on MXene toward an efficient bifunctional electrode with enhanced lithium storage

Abstract It is significant to exploit novel electrode materials because at present the severe capacity decline and slow ion kinetics limit the broad application of lithium-based batteries. Herein, we have prepared the metal–organic frameworks-derived CoP anchored on Ti3C2 MXene (MOFs-CoP@MXene) and fully explored its synergy as an efficient bifunctional electrode for enhanced lithium storage for the first time. It is gratifying that the prepared MOFs-CoP@MXene provides a high capacity of 706.5 mAh g−1 after 200 cycles at 0.2 A g−1, as the anode for lithium-ion batteries (LIBs). It can provide 585.8 mAh g−1 after 1000 cycles with 0.5 A g−1. The MOFs-CoP@MXene anode has robust lithium-ion storage capacity, indicating that it can increase the charge transfer rate and improve Li+ diffusion kinetics with enhanced electrochemical activity. As lithium-sulfur batteries (LSBs) cathode, MOFs-CoP@MXene/S shows 796.9 mAh g−1 after 300 cycles at 0.2C. MOFs-derived CoP coupling with MXene exhibits enhanced capture capacity of sulfur, facilitating the conversion of polysulfides. The results show that the MOFs-CoP@MXene composite prepared for the first time are feasible as both the anode of LIBs and the cathode of LSBs.

Amorphous iron-nickel phosphide nanocone arrays as efficient bifunctional electrodes for overall water splitting

The synthesis of low-cost and highly active electrodes for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is very important for water splitting. In this work, the novel amorphous iron-nickel phosphide (FeP-Ni) nanocone arrays as efficient bifunctional electrodes for overall water splitting have been in-situ assembled on conductive three-dimensional (3D) Ni foam via a facile and mild liquid deposition process. It is found that the FeP-Ni electrode demonstrates highly efficient electrocatalytic performance toward overall water splitting. In 1 M KOH electrolyte, the optimal FeP-Ni electrode drives a current density of 10 mA cm−2 at overpotential of 218 mV for the OER and 120 mV for the HER, and can attain such current density for 25 h without performance regression. Moreover, a two-electrode electrolyzer comprising the FeP-Ni electrodes can afford 10 mA cm−2 electrolysis current at a low cell voltage of 1.62 V and maintain long-term stability, as well as superior to that of the coupled RuO2/NF‖Pt/C/NF cell. Detailed characterizations confirm that the excellent electrocatalytic performances for water splitting are attributed to the unique 3D morphology of nanocone arrays, which could expose more surface active sites, facilitate electrolyte diffusion, and benefit charge transfer and also favorable bubble detachment behavior. Our work presents a facile and cost-effective pathway to design and develop active self-supported electrodes with novel 3D morphology for water electrolysis.

An energy efficient bi-functional electrode for continuous cation-selective capacitive deionization.

Effective ion intercalation nanomaterials provide tremendous opportunities to various deionization systems such as capacitive deionization (CDI) to significantly improve the removal capacity of brackish water desalination. However, the asymmetric design of CDI devices causes a low removal rate due to the indispensable regeneration half-cycle. Furthermore, choices of chloride selective electrodes for such devices are limited. This imposes a big challenge on further improvement of CDI systems. Herein, we report a cation-selective CDI system using a single bi-functional Na2VTi(PO4)3@carbon nanomaterial with redox couples of V4+/V3+ and Ti3+/Ti4+ as an advanced symmetric electrode. The as-prepared continuous desalination set-up shows a superior removal rate of 0.022 mg g-1 s-1 (1.32 mg g-1 min-1) with a high half-cycle removal capacity of 35 mg g-1, and extremely low energy consumption of 0.14 W h g-1 (at a current density of 100 mA g-1). In addition, an extremely high cycle-stability of at least 50 cycles is achieved. The bi-functional intercalation mechanism is investigated by in situ XRD and ex situ XPS. The symmetric device yields a simplified and low-cost configuration with improved energy efficiency and high removal capacity. This opens a new horizon towards the commercialization of CDI technologies.

Metal–Organic Framework-Derived Cu-Doped Co9S8 Nanorod Array with Less Low-Valence Co Sites as Highly Efficient Bifunctional Electrodes for Overall Water Splitting

One of the main goals of current renewable energy research is continuously developing low-cost, robust, and environmentally friendly electrocatalysts to replace scarce and unstable precious metal catalysts. Hence, a novel high-performance electrocatalytic water-splitting material based on a metal–organic framework (MOF)-derived Cu-doped Co9S8 nanorod array was successfully prepared. Using 1,3,5-benzenetricarboxylic acid (H3BTC) as a ligand, a CuCo MOF (CuCo-MOF) nanobelt array precursor was prepared and then transformed into a Cu-Co9S8 nanorod by a simple sulfurization process using thioacetamide as a sulfur source. It is worth noting that the intermediate CuCo-MOF nanobelts play a key role in the generation of nanostructures of the Cu-doped Co9S8 nanorod array. As one of the most promising bifunctional electrocatalysts reported, the Cu-doped Co9S8-6h only needs 260 mV to drive 50 mA cm–2 for oxygen evolution reaction and 62 mV to drive 10 mA cm–2 for hydrogen evolution reaction. When the Cu-doped Co9S8-6h was used as an electrode in a self-made two-electrode system, it requires only 1.49 V of cell voltage to drive 10 mA cm–2, which is one of the smallest open-circuit voltages reported. Density functional theory results show that the superior performance of the Cu-doped Co9S8-6h is attributed to increased conductivity and increased water adsorption energy because of Cu doping. By comparing the water adsorption energy of Co2+, Cu2+, and Co3+, it is proved that the active Cu2+ replaces the inert Co2+, and less low-valence Co2+ sites make the Cu-doped Co9S8-6h show superior catalytic activity. These results demonstrate that the Cu-doped Co9S8-6h nanorod array can be used as an excellent bifunctional electrocatalyst for overall water splitting, and this work will provide an excellent synergistic strategy to energy storage and conversion.

Bifunctional NiCo2Se4 and CoNi2Se4 nanostructures: Efficient electrodes for battery-type supercapacitors and electrocatalysts for the oxygen evolution reaction

We report the fabrication of bimetallic NiCo2Se4 and CoNi2Se4 nanostructures on nickel-foam (Ni-foam) substrates via a potentiostatic-deposition method by adjusting the molar ratio of Ni and Co metals. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses show that burl-like clusters with characteristic fluffy NiCo2Se4 and flake-like CoNi2Se4 hierarchical structures were deposited on the Ni-foam substrates. When used as battery-type electrodes in supercapacitors, both NiCo2Se4 and CoNi2Se4 electrodes exhibited outstanding capacity and good electrochemical properties. The CoNi2Se4 electrode delivered excellent capacity and cycling stability (602Cg–1 at 1Ag–1 and 98.30% retention after 5000 cycles at 40Ag–1) when compared to the NiCo2Se4 electrode (353Cg–1 at 1Ag–1 and 96.83% retention after 5000 cycles at 40Ag–1). Furthermore, as-deposited NiCo2Se4 and CoNi2Se4 hierarchical structures were employed as efficient electrocatalysts for water oxidation in alkaline solutions. NiCo2Se4 and CoNi2Se4 electrocatalysts showed low overpotentials of 257 and 244mV in a 1.0M KOH aqueous solution, respectively. The electrocatalysts also exhibited prolonged stability (NiCo2Se4 and CoNi2Se4 maintained currents of 95.6% and 97.5%, respectively, over 10h), which makes them comparable to well-known Ni and Co-based catalysts. Collectively, the as-deposited NiCo2Se4 and CoNi2Se4 are the most efficient bifunctional electrodes and electrocatalysts for application in battery-type supercapacitors and the oxygen evolution reaction, respectively, and can potentially be applied for energy conversion and storage processes.

Core-shell copper oxide @ nickel/nickel–iron hydroxides nanoarrays enabled efficient bifunctional electrode for overall water splitting

The design of efficient and low-cost electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) remains a significant challenge for the hydrogen production. Herein, CuO nanowires encapsulated by Ni and NiFe hydroxides (CuO@Ni/NiFe hydroxides) in-situ grown on the surface of Cu plate were fabricated via chemical oxidation-calcination process and room-temperature interfacial Galvanic reaction, which were applied to the efficient overall water splitting. Thanks to the improved specific surface area and the conductivity, the optimized core-shell CuO@Ni/NiFe hydroxides nanowire array exhibit impressive OER performance as well as HER activity in 1 M KOH which delivers a current density of 10 mA cm−2 at an overpotential of 230 mV for OER and 125 mV for HER. Significantly, core-shell CuO@Ni/NiFe hydroxides used as bifunctional catalysts for an overall water splitting can achieve a low onset potential of ∼1.50 V and a relatively high specific current density of 40 mA cm−2 at ∼1.73 V. This feasible strategy provides an accumulative opportunity for fabricating low-cost, effective bifunctional catalysts for overall water splitting.