Improving adsorption and purification performance of Bi2WO6/BiOCl by oxygen vacancies

Enhancing adsorption ability of photocatalyst by vacancy is a fascinating strategy. Thus, Bi₂WO₆/BiOCl with millefeuille-like was successfully prepared via multi-pots method. Experimental results discern that BOW-10 can degraded 75.19% doxycycline hydrochloride (DOC, 20 mg/L) in 1 h, which is 1.3 and 3.5-fold larger than Bi₂WO₆ and BiOCl, respectively. The mechanism revealed that OVs (oxygen vacancies) not only promote the adsorption of DOC and O₂ but also augment the activation ability of molecular oxygen. Therefore, photo-induced electrons can rapidly transfer from BiOCl to Bi₂WO₆ via carrier transport channels formed by interface oxygen vacancies (IOVs) under interfacial electric field (IEF) to reduce the adsorbed O₂. Finally, DOC was eliminated by O₂˙^- and h⁺. Moreover, the relationship of surface areas, OVs concentration and the separation efficiency of photo-generated carriers was constructed. Meanwhile, the degradation paths of DOC and the toxicity of the intermediates were comprehensively investigated through DFT theoretical calculation. This research provides an innovation approach to regulate the capability of pollution adsorption and molecular oxygen activation by vacancy engineering and heterostructure engineering.