Synthesis of cobalt vanadium nanomaterials for efficient electrocatalysis of oxygen evolution

A low-cost and high-activity catalyst for oxygen evolution reaction (OER) is the key to the water splitting technology for hydrogen generation. Here we report the use of three solvents, DMF, ethanol and glycol, in the solvothermal synthesis of three nano-catalysts, Co-3(VO4)(2)-I, Co-3(VO4)(2)-II, and Co-3(VO4)(2)-III, respectively. Transmission electron microscope shows Co-3(VO4)(2)-I, II, and III exist as ultrafine nanosheets, ultrathin nanofilms, and ultrafine nanosheet-comprised microspheres, respectively. These Co-3(VO4)(2) catalysts exhibit OER electrocatalysis, among which the Co-3(VO4)(2)-II shows the lowest onset overpotential of 310 mVand only requires a small overpotential of 330 mV to drive current density of 10 mA/cm(2). Due to their high surface free energy, the ultrathin nanofilms of Co-3(VO4)(2)-II exhibits a good immobilization effect with the high electrocatalytic activity for OER.