NiMo@IrO2 bifunctional electrocatalyst for efficient electrochemical hydrogen evolution and chlorine evolution reactions

Hydrogen evolution reaction (HER), chlorine evolution reaction (CER) and oxygen evolution reaction (OER) are electrochemical reactions with industrial applications, such as chlor-alkali industry, water splitting and seawater electrolysis. At present, the research on bifunctional electrode is a hot topic at present, but there are several studies on bifunctional electrode with high HER and CER activities. In this work, a bifunctional catalyst with excellent HER and CER activities has been obtained for the first time by constructing the NixMo100-x alloy modified IrO2 electrode (NixMo100-x@IrO2). The preparation of NixMo100-x@IrO2 electrode is a combination of the thermal decomposition and magnetron sputtering. The electronic structure of the obtained NixMo100-x@IrO2 electrode has obviously changed. There is obvious synergy between IrO2 and NixMo100-x, which leads to the obvious increase of HER and CER activities of NixMo100-x@IrO2. The HER current density of NixMo100-x@IrO2 is higher than the sum of current densities of IrO2 and NixMo100-x in both acidic and alkaline solutions. At an overpotential of 200 mV, the HER current densities of Ni79Mo21@IrO2 can reach 364.1 and 327.5 mA cm-2 in 0.5 M H2SO4 and 1.0 M KOH. The overpotentials at 10 mA cm- 2 (r/10) are 34 and 66 mV in 0.5 M H2SO4 and 1.0 M KOH. Moreover, the CER activity of NixMo100-x@IrO2 is also significantly improved, which significantly exceeds that of IrO2. The r/10 of NixMo100-x@IrO2 is 73 mV in the CER process. And, the CER current density can reach 194.2 mA cm- 2 at an overpotential of 200 mV. In addition, NixMo100-x@IrO2 shows a good stability both for HER and CER.