Surface Engineering to Reduce the Interfacial Resistance for Enhanced Photocatalytic Water Oxidation

Abstract

Interfacial resistance of the charge carriers across TiO2 to cocatalysts is one of the main limiting factors for realizing high photocatalytic efficiency of water oxidation. Herein, an amorphous TiOx layer is introduced on the surface of crystalline TiO2 catalyst to form the core–shell structure (am@TiO2) via an oxidation corrosion method. Owing to the surface disordered Ti–O layer, the obtained am@TiO2 exposes abundant −OH groups for the homogeneous loading of nanosized IrOx, while the charge carrier interfacial migration is substantially enhanced. The as-prepared IrOx-am@TiO2 exhibits photocatalytic water oxidation performance with an O2 evolution rate of 143.6 μmol/g·h, which is approximately 14 times higher than that of the bare am@TiO2. Moreover, an apparent quantum yield (AQY) of 18.99% is obtained under LED-405 illumination. This work provides a direction for improving the photocatalytic performance and helps to gain a fundamental understanding of the water oxidation steps.