A novel sacrificial solvent method to synthesize self-supporting CoS/NiS heterostructure catalyst for efficient oxygen evolution reaction.

Synthesizing catalysts for efficient oxygen evolution reaction (OER) with lower cost and simpler design is of significant importance to achieve sustainable hydrogen production. In this work, we propose a novel "sacrificial solvent method" for the first time. Dicobalt octacarbonyl (Co(CO)), dimethyl sulfoxide (DMSO), and Ni foam (NF) were used as the raw materials in the solvothermal process. DMSO played the role of both the sacrificial solvent and the sulfur source. Through the self-consumption of DMSO, we finally obtained the CoS/NiS heterostructure supported on the NF (CoS/NiS@NF) in one step. The CoS/NiS@NF catalyst exhibited excellent OER activity in alkaline environment, with an overpotential of only 264 mV at a current density of 20 mA cm, a low Tafel slope of 68.28 mV dec and maintained its current density after 20 h of constant potential testing. This work introduces a new method for synthesizing metal sulfide catalysts using DMSO as a sacrificial solvent. It provides broader opportunities for the development of more efficient and sustainable catalysts for energy conversion and storage.