An organic ligand promoting the electrocatalytic activity of cobalt oxide for the hydrogen evolution reaction

Abstract

In electrocatalytic water splitting, active, stable and low-cost hydrogen evolution electrocatalysts play key roles in the conversion and storage of renewable energy sources. Here we report that the incorporation of an organic ligand (2,2′-dipyridylamine (Hdpa)) into Co₃O₄ dramatically enhanced its electrocatalytic activity for the hydrogen evolution reaction. The co-electrodeposited Co₃O₄-dpa-C nanosheets on a glassy carbon electrode exhibited a low overpotential of 54 mV to achieve a current density of 10 mA cm⁻² for the HER, much lower than that of pure Co₃O₄ (324 mV at 10 mA cm⁻²). These results indicate that the molecular Co complex anchored on the surface of Co₃O₄ acts as the catalytic center and cooperatively promotes the hydrogen evolution reaction at the interface of the Co₃O₄ support under alkaline conditions.