The electrocatalytic properties of an IrO2/SnO2 catalyst using SnO2 as a support and an assisting reagent for the oxygen evolution reaction

Highlights: ► Enhanced performance was attributed to high surface area and desorption of hydroxy. ► Optimum condition was found at the mass ratio of iridium to tin was 2:1. ► Terminal voltage of water electrolysis was 1.70 V at 80 °C and 2 A cm−2. - Abstract: Electrocatalysts made of IrO2/SnO2 were prepared using the Adams method for solid polymer electrolyte (SPE) water electrolysis. The physicochemical properties of the catalyst were characterized via X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrochemical properties of the catalyst were investigated using cyclic voltammetry (CV), electrochemical impendence spectroscopy (EIS), chronopotentiometry and Tafel curve measurements in 0.1 mol L−1 H2SO4 at room temperature. The test results showed that the catalytic properties of IrO2/SnO2 depended on the mass ratio of iridium to tin, and that the optimal mass ratio was 2:1. The optimized catalyst was applied to a membrane electrode assembly (MEA), and the stationary current–potential relationships were determined. With an IrO2/SnO2 (2:1) anode, a 40% Pt/C cathode and a total noble metal (Ir, Pt) loading of 1.2 mg cm−2, the terminal applied potential difference of the water electrolysis was 1.70 V at 2 A cm−2 and 80 °C.