Nickel-iron layered double hydroxide and CoMoO4 composites supported on nickel foam as efficient bifunctional catalyst for water electrolysis

Hydrogen is promising fuel to replace fossil fuel due to its characteristics of high energy density and zero-emission. Water electrolysis is believed to play a prominent role for hydrogen generation and carbon neutrality. Designing economical and efficient electrocatalysts is crucial for hydrogen harvest from water electrolysis. Herein, nickel foam supported nickel–iron layered double hydroxide (NiFe-LDH) and CoMoO 4 nanosheet composites (NiFe-LDH/CoMoO 4 /NF) was fabricated by stepwise hydrothermal route. NiFe-LDH/CoMoO 4 /NF exhibited improved performance towards oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline environment. When NiFe-LDH/CoMoO 4 /NF was adopted as bifunctional catalyst for water electrolysis in 1 M KOH, the cell voltage was only 1.58 V and 1.79 V at 10 mA cm −2 and 100 mA cm −2 , respectively. Besides, NiFe-LDH/CoMoO 4 /NF exhibited tremendous durability for at least 100 h at high current density of 500 mA cm −2 . The improved activity and durability were due to: (1) strong interaction between Mo 6+ and Fe 2+/3+ , Co 2+/3+ , Ni 2+/3+ modulated the electronic structure thus promoted the adsorption/desorption of intermediates; (2) mixed-crystalline structure exposed high density of defect sites as active center to boost electrocatalytic reaction. The proposed multicomponent collaborative and crystalline engineering strategy can greatly improve the efficiency of hydrogen generation, and may be applicable for other electrocatalytic processes.