Role of defects on TiO2/SiO2composites for boosting photocatalytic water splitting

Abstract

Defect engineering of semiconductor photocatalysts is considered as an evolving strategy to adjust their physiochemical properties and boost photoreactivity of the materials. Here, hydrogenation and UV light pre-treatment of TiO2/SiO2 composite with the ratio of 9 : 1 (9TiO2/1SiO2) were conducted to generate Ti3+ and non-bridging oxygen holes center (NBOHC) defects, respectively. The 9TiO2/1SiO2 composite exhibited much higher photocatalytic water splitting than neat TiO2 and SiO2 as a consequence of the electronic structure effects induced by the defect sites. Electron paramagnetic resonance (EPR) indicated that hydrogenated and UV light pre-treated of 9TiO2/1SiO2 boosted a higher density of Ti3+ and NBOHC defect which could serve to suppress photogenerated electron-hole pair recombination and act as shallow donors to trap photoexcited electron. Overall, both defect sites in 9TiO2/1SiO2 delivered advantageous characteristic relative to neat TiO2 and SiO2 with the finding clearly illustrating the value of defect engineering in enhancing photocatalytic performance. This journal is