A Type-I Heterojunction by Anchoring Ultrafine Cu2O on Defective TiO2 Framework for Efficient Photocatalytic H2 Production

Abstract

The metal–organic framework (MOF) contains abundant metal ions and organic ligands, and is an excellent self-sacrificial template or precursor for further assembly of functional composites. Herein, MOF-derived defective TiO2 anchored by ultrafine Cu2O nanoparticles has been successfully prepared. In situ formation of type-I heterojunctions between defective TiO2 and ultrafine Cu2O nanoparticles and their application in photocatalytic H2 evolution were demonstrated. Series of composites with varying amounts of Cu2O from 1% to 10% were synthesized. 5 wt % Cu2O loading leads to a H2 generation activity of 4.81 mmol g –1 h –1 under UV–visible light, which is about 3.2 times larger than that of MOF-derived defective TiO2 (1.49 mmol g –1 h –1). It is found that the existence of Ti3+ and Ov defects in the prepared Cu2O/D-TiO2 (defective TiO2) introduces a new local energy level in the forbidden band, which is responsible for effective charge separation. The uniform distribution of Cu2O nanoparticles in defective TiO2 enables close surface contact, enhanced visible light absorption, and electron-transfer efficiency through the formation of heterojunction. This work provides valuable guidelines for exploiting high-performance MOF-derived photocatalysts for the photocatalytic H2 evolution.