▎ 摘　　要

A high efficiency hybrid electrocatalyst (Co3O4-rGO-gC(3)N(4)) was developed via a facile method of doping cobalt oxide (Co3O4) on reduced graphene oxide (rGO) supported by graphitic carbon nitride (GCN, g-C3N4). The synthesized composite was tested for supercapacitance and hydrogen evolution reaction (HER) activity. The results demonstrate excellent supercapacitance properties based on tests with two electrode configurations to produce capacitance of 675 F g(-1) at a current density of 1 A g(-1). The electrode showed excellent capacitance retention ability (85.4%), cycling stability (93%), high energy density (28.3 W h kg(-1)) and power density (0.8 kW kg(-1)). The composite exhibited excellent electrocatalytic activity for hydrogen evolution reaction (HER) with a Tafel slope of 65 mV.dec(-1), a low onset overpotential of 75 mV and an overpotential of -180 mV at a current density of 10 mA cm(-2). The performance of the doped hybrid was found to be superior to those reported for other metallic and non-metallic materials.