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/Ni7S6 with a heterogeneous interface supported on nickel foam (CoV-NiSx/NF) through a simple hydrothermal and vulcanization method. The heterogeneous interfaces formed by NiS and Ni7S6 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-NiSx/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/Ni7S6 is the actual OER catalytic active component. The assembled electrolyzer with Pt/C/NF and CoV-NiSx/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.