Surface cationic and anionic dual vacancies enhancing photocatalytic activity of Bi2WO6

Organic pollutants and drug-resistant bacteria in water have severely threatened the health of humans and animals, and traditional sewage treatment techniques are restricted by their high cost and complex process. Photocatalysis is one of the most promising tactics to tackle above problems owing to its safety, cleaning and low cost. However, the fast recombination of photogenerated electrons and holes of semiconductors impedes their wide application. In this study, Bi2WO6 with surface tungsten vacancies (WVs) and oxygen vacancies (OVs) were prepared by a facile alkali etching method, and the concentration of vacancies was adjusted by controlling the etching time. The simultaneous introduction of WVs and OVs into Bi2WO6 can not only enhance the separation of photogenerated carriers, but also decrease charge transfer resistance, significantly boosting photocatalytic pollutant degradation and antibacterial performance. As a result, the bisphenol A (BPA) degradation efficiency of Bi2WO6 etched for 2 h (BWO-E2) can reach 90% within 120 min under simulated sunlight irradiation and the Escherichia coli (E. coli) inactivation efficiency achieves 92% within 90 min under visible light irradiation. This work may shed new light on designing highly-efficient photocatalysts with multiple defects.