Cobalt-vanadium bimetal-based nanoplates for efficient overall water splitting

Abstract

The development of effective and low-cost catalysts for overall water splitting is essential for clean production of hydrogen from water. In this paper, we report the synthesis of cobalt-vanadium (Co-V) bimetal-based catalysts for the effective water splitting. The Co2V2O7· x H2O nanoplates containing both Co and V elements were selected as the precursors. After the calcination under NH3 atmosphere, the Co2VO4 and Co/VN could be obtained just by tuning the calcination temperature. Electrochemical tests indicated that the Co-V bimetal-based materials could be used as active hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalyst by regulating their structure. The Co/VN showed good performance for HER with the onset potential of 68 mV and can achieve a current density of 10 mA cm−2 at an overpotential of 92 mV . Meanwhile, the Co2VO4 exhibited the obvious OER performance with overpotential of 300 mV to achieve a current density of 10 mA cm−2. When the Co2VO4 and Co/VN were used as the anode and cathode in a two-electrode system, respectively, the cell needed a voltage of 1.65 V to achieve 10 mA cm−2 together with good stability. This work would be indicative to constructing Co-V bimetal-based catalysts for the catalytic application.