Effect of Surface Site Defects on Photocatalytic Properties of BiVO<sub>4</sub>/TiO<sub>2</sub> Heterojunction for Enhanced Methylene Blue Degradation
Sahar Mansour, R. Akkari, Semy Ben Chaabene, Mongia Saïd Zina
Abstract
Combining a super photoresponsive BiVO 4 catalyst to the large band gap TiO 2 material seems to be a great interest in order to improve the visible‐light‐driven photodegradation of hazardous pollutants. BiVO 4 /TiO 2 heterojunction composites have been synthesized via a simple one‐pot hydrothermal route. Herein, we carefully highlighted the effect of BiVO 4 content on the physicochemical and photocatalytic properties of solids towards the decomposition of methylene blue (MB) under solar light irradiation. The main results revealed that the formation of the heterostructures catalyst by incorporating BiVO 4 into TiO 2 stabilizes the anatase phase of TiO 2 by inhibiting its crystal growth and improves significantly the light absorbance of titanium dioxide. The results showed that the best photocatalytic performance is assigned to the catalyst with 2 wt% BiVO 4 loading which is higher than both pure BiVO 4 and TiO 2 . This improvement of photocatalytic activity is related to the synergetic effect between both materials. Furthermore, the constructed junction leads to an increase in the concentration of oxygen defects on the semiconductor surface which could create an acceptor energy level into the valence band of TiO 2 . Four cyclic runs for the photocatalytic degradation of MB on BiVO 4 /TiO 2 composite revealed its stability and sustainable reusability.