A Type-I Heterojunction by Anchoring Ultrafine Cu<sub>2</sub>O on Defective TiO<sub>2</sub> Framework for Efficient Photocatalytic H<sub>2</sub> Production
Jiamei Cao, Jiankang Zhang, Wangui Guo, Hao Chen, Jinghua Li, Dengwei Jing, Bing Luo, Lijing Ma
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 TiO 2 anchored by ultrafine Cu 2 O nanoparticles has been successfully prepared. In situ formation of type-I heterojunctions between defective TiO 2 and ultrafine Cu 2 O nanoparticles and their application in photocatalytic H 2 evolution were demonstrated. Series of composites with varying amounts of Cu 2 O from 1% to 10% were synthesized. 5 wt % Cu 2 O loading leads to a H 2 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 TiO 2 (1.49 mmol g –1 h –1 ). It is found that the existence of Ti 3+ and O v defects in the prepared Cu 2 O/D-TiO 2 (defective TiO 2 ) introduces a new local energy level in the forbidden band, which is responsible for effective charge separation. The uniform distribution of Cu 2 O nanoparticles in defective TiO 2 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 H 2 evolution.