Ni-based sulfides@V2O5 nanoarrays with interfacial effect to improve overall water splitting

Abstract

Exploiting low-cost and highly effective electrocatalysts is crucial to enhancing water splitting and developing the environmental hydrogen economy. Herein, the NiS/Ni₃S₂@V₂O₅ nanoarrays grown in situ on Ni foam (NF) are fabricated by a simple hydrothermal process for different reaction times. The V₂O₅ acts as a shell and Ni-based sulfides act as cores. Interestingly, the NiS/Ni₃S₂@V₂O₅/NF-16h reveals superb electrocatalytic activity and stability in an alkaline media, the overpotentials for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are only 32 and 182 mV at 10 mA cm⁻², respectively, and eminent durability over 100 h. Moreover, the cell voltage for the hydrolysis process requires only 1.46 V at 10 mA cm⁻². According to density functional theory (DFT) computations, the strong interfacial effect modulates the electronic properties of Ni and S atoms, endowing them with optimal binding strength to H⁎ and oxygenated intermediates, thus leading to their outstanding catalytic performance for water splitting. This study offers a promising strategy for constructing cost-efficient bifunctional electrocatalysts.