A 2D–2D BiO2−x/Bi2WO6 composite assembled via layer on layer and application in the abatement of the aqueous tetracycline

Abstract

Tetracyclines (TCs) are one of the most common types of antibiotics. In this investigation, a 2D–2D BiO2−x/Bi2WO6 composite has been assembled via growing Bi2WO6 in situ on the sheets of BiO2−x by a simple hydrothermal process and has been applied to removal residual TCs in waterbody. The XRD, SEM, TEM, and XPS analyses reveal that BiO2−x/Bi2WO6 composite is a compact 2D–2D heterojunction and exhibit rich oxygen vacancy. Among the series of composites with the different ratios, 20BiO2−x/Bi2WO6 displays a more excellent visible-light photocatalytic performance with a 96.4% degradation rate of TC, compared to pure Bi2WO6 (47.9%) and BiO2−x (73.3%). The enhanced photodegraded mechanism is revealed in view of the XPS analysis, ESR spectra and density function theory (DFT) calculation. The excellent photocatalytic performance is attributed to the BiO2−x/Bi2WO6 heterojunction and the generation of more oxygen vacancies originated from the co-shared Bi species and redox couple Bi5+/Bi3+ pairs in composite, which will increase the light trapping ability, accelerate the electron transfer, induce a strong redox, and lead to the excellent photo-degraded activity for aqueous TC. This research provides a new insight into the development of the novel bismuth base photocatalyst via growing in situ strategy in the application to photo-catalytically decompose aqueous antibiotic residues.