Enhanced electrocatalytic HER performance of non-noble metal nickel by introduction of divanadium trioxide

Water dissociation, hydrogen adsorption and hydrogen desorption are three important processes for the electrocatalytic hydrogen evolution reaction in alkaline solution. According to the previous report that V-O species can promote the dissociation of water in the oxygen evolution reaction (OER), we wondered if introduction of V-O species to hydrogen evolution reaction (HER) electrocatalyst could also enhance water dissociation, and consequently improve the HER performance. To check this assumption, novel Ni/V2O3 composite was prepared. The obtained electrode exhibits excellent performance including much lower overpotential (44 mV at 10 mA cm(-2)) and Tafel slope value (38 mV dec(-1)) compared to pure Ni and V2O3 electrodes. In addition, the performance of Ni/V2O3 is comparable to commercial Pt/C electrode. V2O3 was proved to increase the Electrochemical Active Surface Area (ECSA) of Ni/V2O3, which is an important reason for the increased HER performance of Ni/V2O3. Besides that, according to the combined results of Temperature-Programed Reduction (TPR) measurement, CO2 Adsorption, Contact Angle test and Density Functional Theory (DFT) calculation, it is believed that introduction of V2O3 can promote the process of water dissociation as expected, as well as the hydrogen adsorption-desorption, and bubble separation, all of which together improves the HER performance of non-noble metal Ni. (C) 2019 Elsevier Ltd. All rights reserved.