Photoreactivity and mechanism of BiPO 4 /WO 3 heterojunction photocatalysts under simulant sunlight irradiation

Considering the practical use, it is of important value to design full-spectrum photocatalysts that can absorb natural sunlight for photodegrading organic contaminants. A series of BiPO4/WO3 heterojunction catalysts with different WO3 contents were readily synthesized via a facile hydrothermal route. Under simulant sunlight irradiation, the photocatalytic activity of the as-prepared products was evaluated by degrading rhodamine B (RhB) solution. Results demonstrated that the most enhanced RhB degradation of 77.2% could be achieved in the BiPO4/WO3 composite with molar ratio of WO3 to BiPO4 to be 2:1, which was about 4.9 and 2.1 times higher than pure BiPO4 (15.9%) and WO3 (37.8%), respectively. During the photocatalytic process of BiPO4/WO3 composite, the photoinduced electrons in BiPO4 would transfer to WO3 while the photoinduced holes in WO3 could easily inject to BiPO4 through their intimate contact interfaces, thus leading to an efficient transfer and separation of interfacial charge carriers. Moreover, the interaction of BiPO4 and WO3 could also extend the region of the absorption spectrum, which then benefited the improvement of photocatalytic activity.