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

Abstract

CBr bond activation is a critical step in the degradation of organic halogenated pollutants. Herein, by introducing oxygen vacancies with different concentration gradients into Bi2WO6, 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 Bi2WO6 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 Bi2WO6 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.