Indium Single Atoms Supported on S-Scheme Cu₃P/TiO₂ as a Photocatalyst for Hydrogen Production

Abstract

Photocatalytic splitting of water for hydrogen production has great developing potentiality. However, owing to the high recombination of photogenerated electron–hole pairs, the low photocatalytic activity limits its application. Metal single atom loading is an effective method to enhance the photocatalytic activity, but further clarification of the micromechanism is needed and important. In this work, an S-scheme Cu3P/TiO2 photocatalyst loaded with the In single atom (InSA) was prepared by the photodeposition method. Irradiated by a 300 W Xe lamp, the H2 production rate of Cu3P/InSA-TiO2 reaches 8.50 mmol g–1 h–1, which is 10.6 times that of TiO2 and 1.4 times that of Cu3P/TiO2 (methanol as the scavenger). Further analysis and calculations with density functional theory suggest that the loaded InSA replace the surface Ti atoms of TiO2. The remarkable photocatalytic activity is ascribed to the fact that the S-scheme heterojunction greatly facilitates the separation of the photogenerated carriers, while the introduction of InSA provides a channel for the charge transport at the heterojunction interface, which further enhances the mobility and reduces the recombination of the photocarriers, thus enhancing the photocatalytic H2 evolution property. This work provides an effective method to increase the photocatalytic H2 production activity, as well as deepens the understanding of the activity-enhancing mechanism by loading a metal single atom.