Polysulfide induced synthesis of Mo doped NiSx based on solid nanoplate arrays for efficient oxygen evolution catalysis

Abstract

Crystal structure and morphology can be regulated by inducing the positioning growth of metal sulfide, which is an efficient strategy to improve the oxygen evolution activity of the anode. Herein, solid NiMoO₄ nanoplate arrays were used as cages to immobilize the metal source, and Mo doped NiS_x is obtained by in situ solvothermal sulfuration reaction with polysulfide as the sulfur source. The electronic structure, conductivity, crystallographic phase and microscopic morphology of oxygen evolution catalysts could be controlled simultaneously by polysulfide induced solid metal oxide sulfidation, thereby greatly improving their electrocatalytic oxygen evolution activity. Benefiting from these, the prepared Mo doped nickel-sulfur electrodes show great performance toward the oxygen evolution reaction with overpotentials of 184 mV and 240 mV at current densities of 50 and 100 mA cm⁻² in alkaline electrolyte. This study provides a new pathway by polysulfide induced sulfidation based on solid metal oxide for developing metal sulfide electrode materials with high oxygen evolution reaction performance for overall water splitting.