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.
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