Effect of Surface Site Defects on Photocatalytic Properties of BiVO4/TiO2Heterojunction for Enhanced Methylene Blue Degradation

Abstract

Combining a super photoresponsive BiVO4 catalyst to the large band gap TiO2 material seems to be a great interest in order to improve the visible-light-driven photodegradation of hazardous pollutants. BiVO4/TiO2 heterojunction composites have been synthesized via a simple one-pot hydrothermal route. Herein, we carefully highlighted the effect of BiVO4 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 BiVO4 into TiO2 stabilizes the anatase phase of TiO2 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% BiVO4 loading which is higher than both pure BiVO4 and TiO2. 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 TiO2. Four cyclic runs for the photocatalytic degradation of MB on BiVO4/TiO2 composite revealed its stability and sustainable reusability.