Oxygen vacancies enriched Bi2WO6 for enhanced decabromodiphenyl ether photodegradation via C-Br bond activation

C Br bond activation is a critical step in the degradation of organic halogenated pollutants. Herein, by introducing oxygen vacancies with different concentration gradients into Bi 2 WO 6 , the CBr bond in decabromodiphenyl ether (BDE209) is activated, so that BDE209 is successfully dehalogenated under visible light. The study shows that the degradation rate of BDE209 on Bi 2 WO 6 is determined by both interface defects and crystallinity. Good crystallinity is conducive to the generation and separation of photogenerated electrons and holes, and an appropriate defect concentration can promote the C-Br activation of BDE209. In addition, through the tracking analysis of the degradation products of BDE209, the content of the meta -debromination products of BDE209 on Bi 2 WO 6 is significantly higher than that of the ortho- and para- debromination products, indicating that the reduction reaction is a position selective multi-electron mechanism. The study shows that oxygen vacancy assisted debromination is an excellent strategy for photocatalytic treatment of halogenated flame retardant pollutants.