Facile room-temperature synthesis of cobalt sulphide for efficient oxygen evolution reaction

Abstract

Abstract The electrolysis of water is one of the most promising strategies to produce renewable fuels and it is important to develop an energy-conserving, low-cost and easily prepared electrocatalyst for oxygen evolution reaction (OER). In this work, Ni foam supported Co 4 S 3 (Co 4 S 3 /NF) was fabricated by a facile one-step approach at room temperature and exhibited excellent OER performance in alkaline media. Specifically, the Co 4 S 3 /NF electrocatalysts showed a small overpotential of only 340 mV to reach a current density of 100 mA cm −2 and a Tafel slope of 71.6 mV dec −1 in alkaline media. More importantly, excellent stability was achieved under a constant current density of 100 mA cm −2 for 100 h and the OER performance of the catalyst was improved after 1400 cycles of linear sweep voltammetry tests in alkaline media. Furthermore, the underpinning mechanism of action was studied by measuring the change of valence states for different elements to elucidate the structural evolution and active species during the electrocatalytic process.