Rational interface engineering of Cu2S–CoOx/CF enhances oxygen evolution reaction activity

Abstract

Interface engineering is the most direct and efficient way to enhance the oxygen evolution reaction (OER) activity of transition-metal sulfides (TMSs). However, present methods of engineering nano-interfaces remain to be improved. Here, we present a nitrate-pyrolysis method to create a sulfide–oxide interface on Cu₂S for the first time. Specifically, a CoO_x decorated Cu₂S nanowire array on Cu foam (Cu₂S–CoO_x/CF) is prepared successfully, and the XPS result demonstrates the interfacial connection between Cu₂S and CoO_x. To afford a current density of 25 mA cm⁻², Cu₂S–CoO_x/CF needs an overpotential of 255 mV, lower than that of Cu₂S/CF (354 mV) and CoO_x/CC (378 mV). These results indicate that the introduction of the sulfide–oxide interface is an efficient means to enhance the OER activity of Cu₂S. And this paper should provide a novel route for more explorations in interface engineering for TMSs.