Characterization of Ti electrodes electrophoretically coated with IrO2-Ta2O5 films with different Ir:Ta molar ratios

Abstract Titanium electrodes coated with transition metal oxides are used in many applications such as the electrogeneration of hydroxyl radicals (•OH) via catalytic water oxidation. Here, we present electrochemical measurements of IrO2-Ta2O5∣Ti electrodes with four different Ir:Ta ratios in the coating (100:0, 70:30, 30:70, 0:100) to better understand their electrochemical behavior. From the results, an Ir:Ta content of 70:30 reveals a homogeneous morphology, an outstanding mechanical stability, and the best generation of •OH radicals due to a cooperative enhancement of the electrocatalytic and proton (H+) transfer properties of IrO2 and Ta2O5, which are complemented by a small ohmic drop due to a junction established during the electrophoretic deposition of IrO2 and Ta2O5. The electrochemical data in this work in conjunction with density functional theory calculations provide in-depth insights into the outstanding electrocatalytic properties of the as-prepared IrO2-Ta2O5∣Ti electrodes, which may have applications in environmental processes.