Construction of Bi2WO6 composites with carbon-coated Cu2O for effective degradation of tetracycline

It is of great significance to achieve superior degradation of contaminants by developing efficient and stable photocatalysts . To boost the photocatalytic performance of Bi 2 WO 6 for tetracycline degradation, the Bi 2 WO 6 composites ( Bi 2 WO 6 /C@Cu 2 O) were constructed by introducing Cu 2 O coated by carbon layer (C@Cu 2 O with 5 wt% of Bi 2 WO 6 ) in this study. Bi 2 WO 6 /C@Cu 2 O presents an excellent performance on tetracycline degradation because of the generation of more active species as ∙ O 2 - and ∙ OH. Its kinetic rate constant k was 2.8 times of pure Bi 2 WO 6 and tetracycline degradation efficiency maintained outstanding stability even after 4 cycles. This benefits from the higher photogenerated charge separation and electron transfer possessed by Bi 2 WO 6 /C@Cu 2 O compared to Bi 2 WO 6 . Various intermediates of tetracycline degradation were identified and the possible degradation pathways were proposed. The tetracycline degradation by Bi 2 WO 6 /C@Cu 2 O followed a Z-scheme photocatalysis mechanism. In addition to acting as the protective layer of Cu 2 O to attenuate the photo-corrosion of Cu 2 O, the oxygen containing functional groups C O on the surface of carbon layer could provide an electron transfer channel between the interface of Bi 2 WO 6 and Cu 2 O to reduce the interfacial charge-transfer resistance and accelerate the electron transfer.