Nanoflower-like cobalt-based sulfides catalyst with high electrocatalytic activity for oxygen evolution reaction

Abstract

It is crucial to design nonprecious metal electrocatalysts with highly active for oxygen evolution reaction. To date, transition metal sulfides (TMSs) have become alternatives to replace noble metal-based (RuO2 and IrO2) catalysts because of their excellent catalytic activity. Hence, a facile method through one-step solvothermal is proposed to synthesize nanoflower-like Co1-xS/CoS2-2 as efficient electrocatalyst for oxygen evolution reaction. The obtained electrocatalyst has improved charge-transfer kinetics of the sulfidation process and accelerated gas diffusion enabled by nanosheets structure. As a result, the Co1-xS/CoS2-2 requires overpotential of 310 mV for OER to drive a current density of 10 mA cm−2. The sample shows excellent electrochemical stability at the potential of 1.54 V (vs. RHE) to deliver the current density of 10 mA cm−2. After seven hours of OER reaction, the current density maintained at 8.23 mA cm−2, presenting long-term stability.