Bifunctional electrocatalysts for water splitting from a bimetallic (V doped-NixFey) Metal–Organic framework MOF@Graphene oxide composite

An ongoing challenge still lies in the exploration of proficient electrocatalysts from earth-abundant non-precious metals instead of noble metal-based catalysts for clean hydrogen energy through large-Scale electrochemical water splitting. However, developing a non-precious transition metals based, stable electrocatalyst for cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) is important challenge for modern energy conversion technology. In this report Vanadium doped bimetallic nickel-iron nanoarray, fabricated by carbon supported architecture through carbonization process for electrochemical water splitting. Three types of catalysts were prepared in different molar ratio of Ni/Fe. The electrocatalytic performance demonstrated that the catalyst with equal mole ratio (0.06:0.06) of Ni/Fe possess high catalytic activity for both OER and HER in alkaline and acidic medium. Besides, our findings revealed that the doping of vanadium could play a strong synergetic effect with Ni/Fe, which provide a small overpotential of 90 mV and 210 mV at 10 mA cm^?2 for HER and OER respectively compared to the other two catalyst counterparts. Also, the catalyst with 1:1 (Ni/Fe) molar ratio showed a high current density of 208 mA cm^?2 for HER at 0.5 M H₂SO₄ and 579 mA cm^?2 for OER at 1 M KOH solution, the both current densities are much higher than the other two catalysts (different Ni/Fe ratio). In addition, the presented catalysts showed extremely good durability, reflecting in more than 20 h of consistent Chronoamprometry study at fixed overpotential η = 250 mV without any visible voltage elevation. Similarly, the (Ni/Fe) equal ratio catalyst showed better corrosion potential 0.209 V vs Ag/AgCl and lower current density 0.594 × 10^?12 A cm^?2 in high alkaline medium. The V-doping, MOF/GO surface defects are significantly increased the corrosion potential of the V-Ni_xFe_y-MOF/GO electrocatalyst. Besides, the water electrolyzed products were analysed by gas chromatography to get clear insights on the formed H₂ and O₂ products.     

Tracking the role of Fe in NiFe-layered double hydroxide for solar water oxidation and prototype demonstration towards PV assisted solar water-splitting

NiFe based layered hydroxides (LDH) is an efficient oxygen evolution catalysts used in energy conversion and storage devices. Herein, we used in-situ electrochemical impedance spectroscopy (EIS) to study the role of Fe in improving the oxygen evolution reaction (OER) of NiFe-LDH, as an alternative to expensive techniques. Optimized Ni_0·46Fe_0.54-LDH showed Tafel slope of 49 mV dec^?1 and over potential of~340 mV at 10 mA cm^?2. Increase in Fe content in NiFe-LDH, lowered the average oxidation of the Ni, revealing the stabilization of lower oxidation state of Ni. Potential dependent EIS supported this effect showing that multi-metal LDH favors the surface intermediate stabilization thereby reducing the overall charge transfer resistance at interface compared to mono metal catalysis. Surface intermediate relaxation process is dependent on Fe content and is playing a role in deciding the rate limiting step. The Fe–O–Ni linkages in FeO_x-NiFe-LDH systems exert partial charge transfer activation for OER process. A prototype demonstration of overall water splitting using a photovoltaic-electrolyser assembly is conducted with Ni_0·46Fe_0.54-LDH as bifunctional catalysts which yields a constant current density of ~10 mA cm^?2 at a V_oc = 1.65 V. Present study provide experimental evidence of improved activity of FeO_x-NiFe-LDH with the help of potential dependent EIS studies and makes practically attractive for renewable energy conversion and storage applications.     

Adjusting electronic structure coupling of Fe–Ni2P (NiFeP-MOF) multilevel structure for ultra-activity and durable catalytic water oxidation

Efficient electrocatalyst for alkaline oxygen evolution reaction is the critical core to the wide application of metal-air energy storage and water electrolysis hydrogen energy. Therefore, appropriate design of highly active and stable non-noble metal oxygen evolution electrocatalyst with good electronic structure and multilevel structure is both a goal and a challenge. Here, we report a Fe–Ni₂P electrocatalyst (NiFeP-MOF) with multilevel structure, which was obtained by anion exchange on the basis of Fe–Ni(OH)₂ (NiFe-MOF) grown on nickel foam in situ by solvothermal method. As expected, Fe substitution regulates the Ni oxidation state in the NiFeP-MOF and realizes electronic structure coupling, showing a highly active and stable oxygen evolution reaction (OER) in alkaline electrolyte solution. Specifically, the NiFeP-MOF demonstrates an ultralow overpotentials (232 mV, 10 mA cm^?2; 267 mV 100 mA cm^?2), respectively, an extremely small Tafel slope (34 mV dec^?1). Separately, the electrocatalyst shows an excellent cycle stability at 10 mA cm^?2 for 12 h (43,200 s). More importantly, this work come up with an available policy for the preparation of excellent alkaline hydrolysis electrolysis catalysts and air cathodes with excellent performance.     

Facile construction of well-defined hierarchical NiFe2O4/NiFe layered double hydroxides with a built-in electric field for accelerating water splitting at the high current density

Interfacial charge redistribution induced by a strong built-in electric field can expertly optimize the adsorption energy of hydrogen and hydroxide for improving the catalytic activity. Herein, we develop a well-defined hierarchical NiFe₂O₄/NiFe layered double hydroxides (NFO/NiFe LDH) catalysts, exhibiting superior performance due to the strong interfacial electric field interaction between NiFe₂O₄ nanoparticle layers and NiFe LDH nanosheets. In 1 M KOH, NFO/NiFe LDH needs 251 mV and 130 to drive 50 and 10 mA cm^?2 for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Moreover, only 1.517 V cell voltage is needed to reach 10 mA cm^?2 towards overall water splitting. Notably, under simulated industrial electrolysis conditions, NFO/NiFe LDH only needs 289 mV to drive 1000 mA cm^?2. This work puts a deep insight into the role of the built-in electric field in transition metal-based catalysts for accelerating water splitting and scalable industrial electrolysis applications.     

Amorphous FeOOH decorated hierarchy capillary-liked CoAl LDH catalysts for efficient oxygen evolution reaction

Electrocatalytic water splitting is a promising route for the generation of clean hydrogen. However, the anodic oxygen evolution reaction (OER) suffers greatly from low reaction kinetics and thereby hampers the energy efficiency of alkaline water electrolysers. In recent years, tremendous efforts have been dedicated to the pursuit of highly efficient, low cost and stable electrocatalysts for oxygen evolution reaction. Herein, an amorphous FeOOH roughened capillary-liked CoAl layered double hydroxide (LDH) catalyst grown on nickel foam (denoted as FeOOH–CoAl LDH/NF) was reported for OER electrolysis. The developed FeOOH–CoAl LDH/NF electrode shows excellent OER activity with overpotentials of 228 mV and 250 mV to deliver a current density of 50 mA cm^?2 and 100 mA cm^?2 in 1.0 M KOH solution, respectively, ranking it one of the most promising OER catalysts based on transition-metal-based LDH. This is owed to the formed capillary-liked hierarchy structure with high-porosity as well as the strong electronic interaction between FeOOH and CoAl LDH. The developed morphological engineering approach to build hierarchal porous structures together with facile amorphous FeOOH modification may be extended to other layered double hydroxide catalyst for enhanced OER activities.     

Growth of ultrathin nanosheets of nickel iron layered double hydroxide for the oxygen evolution reaction

Because of low cost and abundance, nickel-iron double layered hydroxide (NiFe LDH) is seen as a viable substitute for noble-metal-based electrodes for the oxygen evolution reaction (OER). Herein, we report the growth of NiFe LDH in the form of fine nanosheets in a single step using benzyl alcohol-mediated chemistry. The electrochemical studies clearly suggest that benzyl alcohol is capable of inducing effective chemical interaction between Ni and Fe in the NiFe LDH. The overpotential to produce benchmark 10 mA cm^?2 (η₁₀) for the NiFe LDH electrode is only ～270 mV_RHE, which is much smaller than those of benchmark IrO₂ (η₁₀ = 318 mV_RHE), nickel hydroxide (η₁₀ = 370 mV_RHE) and iron hydroxide (η₁₀ = 410 mV_RHE) for the OER. The difference of the overpotential requirement increases further with increasing current density, indicating faster kinetics of the OER at the catalytic interface of the NiFe LDH. Estimation of Tafel values verifies this notion – the Tafel slopes of NiFe LDH, Ni(OH)₂, and FeOOH are calculated to be 48.6, 55.8, and 59.3 mV dec^?1, respectively. At η = 270 mV, the turnover frequency (TOF) of the NiFe LDH is 0.48 s^?1, which is ～8 and ～11 folds higher than those of Ni(OH)₂ (0.059 s^?1) and FeOOH (0.042 s^?1). In addition to Tafel and TOF, the NiFe LDH electrode has favorable electrochemically active surface area and electrochemical impedance. The electrochemical stability of the NiFe LDH electrode is assessed by conducting potentiostatic measurements at η = 270 mV_RHE (～10 mA cm^?2) and at η = 355 mV_RHE (～30 mA cm^?2) for 24 h of continuous oxygen production.     

High throughput preparation of Ni–Mo alloy thin films as efficient bifunctional electrocatalysts for water splitting

The synthesis of cost-effective and high-performance electrocatalysts for water splitting is the main challenge in electrochemical hydrogen production. In this study, we adopted a high throughput method to prepare bi-metallic catalysts for oxygen/hydrogen evolution reactions (OER/HER). A series of Ni–Mo alloy electrocatalysts with tunable compositions were prepared by a simple co-sputtering method. Due to the synergistic effect between Ni and Mo, the intrinsic electrocatalytic activity of the Ni–Mo alloy electrocatalysts is improved, resulting in excellent HER and OER performances. The Ni₉₀Mo₁₀ electrocatalyst shows the best HER performance, with an extremely low overpotential of 58 mV at 10 mA cm^?2, while the Ni₄₀Mo₆₀ electrocatalyst shows an overpotential of 258 mV at 10 mA cm^?2 in OER. More significantly, the assembled Ni₄₀Mo₆₀//Ni₉₀Mo₁₀ electrolyzer only needs a cell voltage of 1.57 V to reach 10 mA cm^?2 for overall water splitting.     

Constructing microstructures in nickel-iron layered double hydroxide electrocatalysts by cobalt doping for efficient overall water splitting

The development of Ni–Fe layered double hydroxide (NiFe LDH) catalysts for overall water splitting (OWS) is urgently required. NiFe LDHs are promising catalysts for the oxygen evolution reaction (OER). However, their hydrogen evolution reaction (HER) performance is restricted by slow kinetics. The construction of multiple types of active sites to simultaneously optimise the OER and HER performance is significant for OWS using NiFe LDHs. Hence, a Co-doped NiFe LDH electrocatalyst with dislocations and stacking faults was designed to modulate the electronic structure and generate multiple types of activity sites. The Co_0.03-NiFe_0.97 LDH catalyst only required overpotentials of 280 (50 mA cm⁻², OER) and 170 mV (10 mA cm⁻², HER). However, it reached a current density of 50 mA cm⁻² at 1.53 V during OWS. Co_0.03-NiFe_0.97 LDHs could be stabilised for 140 h at 1.52 V. Furthermore, Co_0.03-NiFe_0.97 LDHs exhibited a higher electrocatalytic activity than commercial Raney nickel and Pt/C||IrO₂ under industrial conditions. The significant specific surface area, high conductivity, and unique microstructures are the major factors contributing to the excellent OWS performance. This study suggests an efficient strategy for introducing microstructures to fabricate catalysts with high activity for application in OWS.     

Identifying high-efficiency Ni-based alloys/(oxy)hydroxides electrocatalysts for oxygen evolution reaction through a rapid screening method

Ni-based (oxy)hydroxides, as a kind of cost-effective oxygen evolution reaction (OER) electrocatalysts to replace precious Ru/Ir-based catalysts, have attracted comprehensive attention. Recently, the nickel utilization has also come under interest in the latest prices soar of nickel. Herein, 41 kinds of Ni-M (oxy)hydroxides (M = Fe, Cu, Co and Cr) are prepared via a quick electrodeposition method to screen Ni-M (oxy)hydroxides. It is observed that OER activity and durability of Ni-M (oxy)hydroxides heavily depend on the content of M, and the Fe plays the best role on OER activity enhancement. The optimum Ni₈Fe₂/Ni(OH)₂/FeOOH (NiFe-8) exhibit a low overpotential of 270 mV at a current density of 10 mA cm^?2 and Tafel slope of 83 mV dec^?1, which are lower than those of other Ni-M (oxy)hydroxides. In addition, the designed NiFe-8 shows superior cycling stability (10,000 times), self-adapting function during 33.01–49.65 h resulting in a 55.56 h long-term operation durability with 15.94 mA cm^?2 ending activity. Such performance together with low preparation cost, Ni-based materials are favorable for enterprises to improve their economic benefit as well as open up an opportunity for mass-producing of them.     

Bifunctional nanoporous ruthenium-nickel alloy nanowire electrocatalysts towards oxygen/hydrogen evolution reaction

A class of ruthenium-nickel alloy catalysts featured with nanoporous nanowires (NPNWs) were synthesized by a strategy combining rapid solidification with two-step dealloying. RuNi NPNWs exhibit excellent electrocatalytic activity and stability for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in which the RuNi-2500 NPNWs catalyst shows an OER overpotential of 327 mV to deliver a current density of 10 mA cm^?2 and the RuNi-0 NPNWs catalyst requires the overpotential of 69 mV at 10 mA cm^?2 showing the best HER activity in alkaline media. Moreover, the RuNi-1500 NPNWs catalyst was used as the bifunctional electrocatalyst in a two-electrode alkaline electrolyzer for water splitting, which exhibits a low cell voltage of 1.553 V and a long-term stability of 24 h at 10 mA cm^?2, demonstrating that the RuNi NPNWs catalysts can be considered as promising bifunctional alkaline electrocatalysts.     

Facile synthesis of highly active monolithic water-separated W-doped Ni–Fe–P catalysts

A new type of highly active and cost-effective nanoporous W-doped Ni–Fe–P catalyst on nickel foam (NF) was synthesized by a facile electroless plating method. The W-doped Ni–Fe–P/NF catalysts exhibit extraordinary catalytic activity for hydrogen evolution reaction (HER) in alkaline media, capable of yielding a current density of −10 mA cm⁻² at an overpotential of only 68 mV. Furthermore, the catalysts also show efficient activity towards oxygen evolution reaction (OER) with an overpotential of 210 mV at j = 10 mA cm⁻² as well. The W-doped Ni–Fe–P/NF electrocatalyst exhibits a long-term durability over 13 h test.     

One-step hydrothermal synthesized 3D P–MoO3/FeCo LDH heterostructure electrocatalysts on Ni foam for high-efficiency oxygen evolution electrocatalysis

Low-cost yet high-efficiency oxygen evolution reaction (OER) catalysts have attracted ardent attention to speed up the development of water electrolysis. Recent researches have shown that layered double hydroxides (LDH) are promising candidates towards OER, but further improvement is still highly demanded for its large-scale practical application in water splitting. Herein, we report a 3D P-doped MoO₃/FeCo LDH/NF (P–MoO₃/FeCo LDH/NF) ultrathin nanosheet heterostructure electrocatalyst with an extremely low overpotentials of 225 mV for delivering a current density of 10 mA cm^?2 for OER and a great durability for at least 80 h by a simple one-step hydrothermal method. Extraordinarily, the P–MoO₃/FeCo LDH catalyst achieves a high current density of 300 mA cm^?2 and even 350 mA cm^?2 at an extremely low overpotential of 297 mV and 302 mV, respectively, which is crucial for the water electrolysis industry. The remarkable performance may be attributed to that the heterostructure between P–MoO₃ and FeCo LDH not only optimizes electronic structure, thus inducing electron transfer from P–MoO₃ to FeCo LDH and then realizing fast electron transfer rates, but also produces more catalytic active sites. Moreover, the synergetic effect between MoO₃ and FeCo LDH also plays an essential role for enhancing the catalytic performances. This work explores the effect of phosphomolybdic acid on the structure, composition and performances of FeCo LDH catalysts, and also provides a simple and cost-effective way to prepare high-efficiency and low-cost layered double hydroxide electrocatalysts for OER.     

A highly active composite electrocatalyst Ni–Fe–P–Nb2O5/NF for overall water splitting

This work demonstrates a facile Nb₂O₅-decorated electrocatalyst to prepare cost-effective Ni–Fe–P–Nb₂O₅/NF and compared HER & OER performance in alkaline media. The prepared electrocatalyst presented an outstanding electrocatalytic performance towards hydrogen evolution reaction, which required a quite low overpotential of 39.05 mV at the current density of ?10 mA cm^?2 in 1 M KOH electrolyte. Moreover, the Ni–Fe–P–Nb₂O₅/NF catalyst also has excellent oxygen evolution efficiency, which needs only 322 mV to reach the current density of 50 mA cm^?2. Furthermore, its electrocatalytic performance towards overall water splitting worked as both cathode and anode achieved a quite low potential of 1.56 V (10 mA cm^?2).     

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.     

In situ growth of NiCoFe-layered double hydroxide through etching Ni foam matrix for highly enhanced oxygen evolution reaction

It is of great significance to develop the nonprecious metal oxide electrocatalysts toward oxygen evolution reaction (OER) for water splitting. Herein we report an in-situ growth of the ternary NiCoFe-layered double hydroxide nanosheets on surface etching nickel foam (NiCoFe LDHs/NF) without adding any nickel precursor. In this method, etching Ni matrix by Fe³⁺ not only provides the slowly released nickel ions, but also intensifies the Fe–Ni interaction between the directly grown active species and Ni foam. Therefore the composition, electronic structure, and morphology of the electrocatalysts can be easily regulated only by adjusting Co²⁺:Fe³⁺ ratio in the precursor solution. The obtained NiCo₁Fe₁ LDH/NF, which is formed in 1:1 Co²⁺:Fe³⁺ solution, has highest content of Ni³⁺ and Co³⁺ active sites and the largest electrochemical active area. It exhibits an outstanding OER performance with a small overpotential of 231 mV at 10 mA cm^?2 and excellent durability at 50 mA cm^?2 in 1.0 M KOH solution.     

Pulse-electrodeposited Ni–Fe–Sn films supported on Ni foam as an excellent bifunctional electrocatalyst for overall water splitting

The development of extremely active bifunctional non-noble electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is pivotal for water splitting but remains challenging. Herein, self-supported Ni–Fe–Sn electrocatalysts were fabricated on nickel foam (NF) through a simple and facile pulse electrodeposition process. Under optimal conditions, the prepared Ni–Fe–Sn electrocatalysts exhibited excellent bifunctional properties in alkaline medium and required ultralow overpotentials of only 27 and 201 mV for HER and OER, respectively, to reach the current density of 10 mA cm^?2. Importantly, the same Ni–Fe–Sn electrocatalyst can be assembled as the anode and the cathode in a two-electrode system. It demanded a fairly low applied voltage of 1.55, 1.72, and 1.87 V to produce 10, 50, and 100 mA cm^?2, respectively, and exhibited excellent long-term stability. The excellent electrocatalytic water splitting performance of the Ni–Fe–Sn film was mainly associated with its intrinsic catalytic activity derived from the modulation of the electronic structures among Ni, Fe, and Sn by using the appropriate atomic ratio of Ni: Fe: Sn.     

Electrodeposition of NiS/Ni2P nanoparticles embedded in amorphous Ni(OH)2 nanosheets as an efficient and durable dual-functional electrocatalyst for overall water splitting

To develop earth-abundant and cost-effective catalysts for overall water splitting is still a major challenge. Herein, a unique “raisins-on-bread” Ni–S–P electrocatalyst with NiS and Ni₂P nanoparticles embedded in amorphous Ni(OH)₂ nanosheets is fabricated on Ni foam by a facile and controllable electrodeposition approach. It only requires an overpotential of 120 mV for HER and 219 mV for OER to reach the current density of 10 mA cm⁻² in 1 M KOH solution. Employed as the anode and cathode, it demonstrates extraordinary electrocatalytic overall water splitting activity (cell voltage of only 1.58 V @ 10 mA cm⁻²) and ultra-stability (160 h @ 10 mA cm⁻² or 120 h @50 mA cm⁻²) in alkaline media. The synergetic electronic interactions, enhanced mass and charge transfers at the heterointerfaces facilitate HER and OER processes. Combined with a silicon PV cell, this Ni–S–P bifunctional catalyst also exhibits highly efficient solar-driven water splitting with a solar-to-hydrogen conversion efficiency of 12.5%.     

Constructing Ni-Modified Co-FcDA nanosheets for enhancing electrocatalytic oxygen evolution reaction

Electrocatalytic water splitting is an emerging technology for the development of maintainable hydrogen energy. It remains challenging to manufacture a stable, efficient, and cost-effective electrocatalyst that can conquer the slow reaction kinetics of water electrolysis. Herein, A metal-organic framework (MOF) based material is manufactured and productively catalyze the oxygen evolution reaction (OER). The introduction of elemental nickel enhances the catalytic activity of Co-FcDA. The results show that single Ni was well doped in the CoNi-FcDA catalysts and the doping of Ni has a great influence on the OER activity of CoNi-FcDA catalysts. CoNi-FcDA displayed a low overpotential of 241 mV to arrive at the benchmark current density (10 mA cm^?2) with a remarkably small Tafel slope of 78.63 mV dec^?1. It surpassed the state-of-the-art electrocatalyst for OER, that is, RuO₂ (260 mV and 97.26 mV dec^?1) in efficiency as well as instability. Density functional theory (DFT) calculations show that suitable Ni doping at the same time can increase the density of states of the Fermi level, resulting in excellent charge density and low intermediate adsorption energy. These discoveries provide a practical route for designing 2D polymetallic nanosheets to optimize catalytic OER performance.     

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.     

Electrodeposition of Mo-doped NiFex nanospheres on 3D graphene fibers for efficient overall alkaline water splitting

Developing efficient bifunctional catalysts for hydrogen and oxygen evolution reactions (HER/OER) has attracted great interest in hydrogen production from water splitting. In this work, a novel material of Mo-doped NiFe_x nanospheres on 3D graphene fibers (Mo-NiFe_x/3DGFs) has been successfully fabricated through a simple and cheap one-step electrodeposition method. The Mo-NiFe_x/3DGFs possessed ultra-high conductivity and specific surface area, greatly benefiting to electrocatalytic hydrolysis activity. And it was found that Fe element could obviously promote OER process, while Mo doping facilitated both OER and HER reactions. We proved that there existed synergetic roles between Fe and Mo element, which could realize the control of the electronic structure and optimize the adsorption/desorption of intermediates. And electrochemical tests showed that the Mo–Ni/3DGFs exhibited a relatively smaller overpotential of 109.9 mV for HER, while the Mo-NiFe_x/3DGFs presented better OER performance with an overpotential of 240.8 mV at the current density of 100 mA cm^-2 in 1.0 M KOH. Finally, a system for overall water splitting constructed by Mo–Ni/3DGFs||Mo–NiFe_0.68/3DGFs electrodes has a low cell voltage of 1.52 V at 10 mA cm^?2 and long-term stability, exceeding most of literature results. Our findings provide insight into possibilities for the simple synthesis of high-performance and cheap catalysts, and laid the foundation for the practical application of transition metal catalysts.