Amorphous iridium oxide coating on TiO2 for efficient electrocatalytic oxygen evolution reaction

Ir-based electrocatalysts are commonly acknowledged as top-performing materials for water oxidation under acidic conditions. Decreasing the precious metal loading and improving the intrinsic activity of Ir sites are vital for creating effective electrocatalysts for PEMWE applications. Here, we employed a simple solvothermal method to create IrOx@TiO2 core-shell structure electrocatalyst for efficient anodic OER in acidic environment. The obtained IrOx@TiO2 requires an overpotential of only 227 mV to achieve 10 mA cm-2 and maintains such stability over 200 h. Furthermore the intrinsic and mass activity of IrOx@TiO2 demonstrate a remarkable improvement of hundreds of times compared to that of IrO2. The core-shell structure of IrOx@TiO2 possesses a high specific surface area, with the amorphous IrOx shell layer enhancing the catalytic activity of the Ir sites. Further structural analysis of the post-OER IrOx@TiO2 revealed that the amorphous IrOx was effectively stabilized and high-valent IrOx generated on its surface may be more favorable for acidic water oxidation process. This study introduces a practical approach for developing high-performance, low-iridium-loading acidic OER electrocatalysts.