Electrochemical Properties of Ti/SnO2-Sb-Ir Electrodes Doped with a Low Iridium Content for the Oxygen Evolution Reaction in an Acidic Environment

Ti/SnO2-Sb-Ir electrodes doped with a low Ir content were prepared, and they were used in acidic water electrolysis for the oxygen evolution reaction (OER). The results showed that an IrO2–SnO2 solid solution was formed, and the electrode surface was relatively compact. The doping of IrO2 could significantly improve the electrocatalytic activity and stability of Ti/SnO2-Sb electrode for OER. The electrode modified with only 5 mol % Ir met the needs of acidic water electrolysis. Meanwhile, the performances of the electrode approached that of Ti/IrO2 when Ir content was only 8 mol %, which resulted from the fact that IrO2 doping improved the chemical stability as well as the electrocatalytic activity of the electrode. Moreover, the deactivation behavior of the electrode was investigated as well. It was mainly ascribed to the chemical composition and morphology change induced by continuous dissolution of the metal oxides, which eventually led to the passivation of the Ti substrate.