Insight into a novel microwave-assisted W doped BiVO4 self-assembled sphere with rich oxygen vacancies oriented on rGO (W-BiVO4-x/rGO) photocatalyst for efficient contaminants removal

Abstract

A novel W doped BiVO4 with rich oxygen vacancies (OVs) oriented on reduced graphene oxide (rGO) photocatalyst (W-BiVO4-x/rGO) was developed by a simple one-step microwave hydrothermal method for efficient removal of ciprofloxacin (CIP) and chlortetracycline (CTC) under visible light. The synergistic effect of W doping, BiVO4 with OVs, and rGO on the enhancement of photocatalytic activity was clarified from experimental and Density Functional Theory (DFT) calculations results. W doping significantly improved the density of photo-generated charge carriers. The introduction of rGO enlarged the specific surface area, expanded the light absorption range, and promoted the charge transfer of BiVO4. OVs both narrowed the band gap and enhanced the generation of O2−. W doping and OVs both enhanced the interactions between BiVO4 and rGO. The CIP degradation rate constant of W-BiVO4-x/rGO photocatalyst was 1.73, 5.32, 6.43, and 10.70 times higher than those of W-BiVO4/rGO, BiVO4/rGO, W-BiVO4, and BiVO4, respectively. Besides, W-BiVO4-x/rGO photocatalyst prepared by microwave hydrothermal method exhibited higher photocatalytic activity and better combination between materials. This study offers a new strategy to address the problem of antibiotic residues in wastewater.