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

Abstract

It is of great significance to achieve superior degradation of contaminants by developing efficient and stable photocatalysts. To boost the photocatalytic performance of Bi2WO6 for tetracycline degradation, the Bi2WO6 composites (Bi2WO6/C@Cu2O) were constructed by introducing Cu2O coated by carbon layer (C@Cu2O with 5 wt% of Bi2WO6) in this study. Bi2WO6/C@Cu2O presents an excellent performance on tetracycline degradation because of the generation of more active species as ∙O2- and ∙OH. Its kinetic rate constant k was 2.8 times of pure Bi2WO6 and tetracycline degradation efficiency maintained outstanding stability even after 4 cycles. This benefits from the higher photogenerated charge separation and electron transfer possessed by Bi2WO6/C@Cu2O compared to Bi2WO6. Various intermediates of tetracycline degradation were identified and the possible degradation pathways were proposed. The tetracycline degradation by Bi2WO6/C@Cu2O followed a Z-scheme photocatalysis mechanism. In addition to acting as the protective layer of Cu2O to attenuate the photo-corrosion of Cu2O, the oxygen containing functional groups CO on the surface of carbon layer could provide an electron transfer channel between the interface of Bi2WO6 and Cu2O to reduce the interfacial charge-transfer resistance and accelerate the electron transfer.