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

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.