Electrochemical study of Ir-Sn-Sb-O materials as catalyst-supports for the oxygen evolution reaction

A novel material, with a general formula of Ir-Sn-Sb-O, was synthesized for use in solid polymer electrolyte water electrolyzers (SPEWEs) by the thermal decomposition of the chloride precursors H2IrCl6, SnCl4 center dot 5H(2)O, and SbCl3 in ethanol. The material functions simultaneously as an electrocatalyst and support for the oxygen evolution reaction (OER). Two different H2IrCl6 proportions in the reaction mixture were tested to observe the effect of this proportion on the electrocatalytic activity and composition of the materials. Physicochemical properties of Ir-Sn-S-O were characterized by X-ray diffraction, scanning electron microscopy. The electrochemical properties of the materials studied were measured using cyclic voltammetry, linear scan voltammetry, and electrochemical impedance spectroscopy. Mechanical mixtures of IrO2 with Vulcan carbon or antimony doped tin oxide were also tested with respect to the OER to compare the properties of Ir-Sn-Sb-O. The results indicate that the catalyst-support materials presented nanometric sizes (1-2 nm) and electrocatalytic properties similar to IrO2 supported on Vulcan carbon but with higher stability toward the oxygen evolution reaction. The synthesized mixed oxides could be a suitable anode material in SPEWEs.