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, SnCl₄·5H₂O, 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.