Cobalt and vanadium dual-doping engineering of NiS/Ni7S6 with heterogeneous interface as efficient electrocatalyst for the oxygen evolution reaction

Developing cost-efficient and high-activity nonprecious metal-based oxygen evolution reaction (OER) electrocatalysts is essential to water electrolysis for hydrogen production. Herein, cobalt and vanadium co-doped NiS/Ni ₇S ₆ with a heterogeneous interface supported on nickel foam (CoV-NiS _x /NF) through a simple hydrothermal and vulcanization method. The heterogeneous interfaces formed by NiS and Ni ₇S ₆ can generate more active centers and modulate electronic distribution of the two. The dual doping of Co and V can provide larger electrical conductivity and optimize the electron structure, achieving robust kinetics for OER reaction. Remarkably, CoV-NiS _x /NF exhibits excellent OER catalytic performance with an overpotential of 261 mV for driving 100 mA cm ⁻². In addition, in-situ Raman indicates the NiOOH converted from NiS/Ni ₇S ₆ is the actual OER catalytic active component. The assembled electrolyzer with Pt/C/NF and CoV-NiS _x/NF as the cathode and anode for overall water splitting only needs a low cell voltage of 1.41 V to yield 10 mA cm ⁻² , outperforming the majority of published OER electrocatalysts based on non-precious metal This study provides a feasible solution using dual-metal doping with a heterogeneous interface design for developing efficient OER electrocatalysts for water electrolysis.