Few-layer WS2 modified BiOBr nanosheets with enhanced broad-spectrum photocatalytic activity towards various pollutants removal.

Abstract

Herein, an efficient broad-spectrum WS2/BiOBr heterostructure with ultrathin nanosheet was successfully prepared by one-pot hydrothermal route. The self-assembled flower-like WS2/BiOBr nanostructure was formed by few-layer WS2 and BiOBr nanosheets. The optimized heterojunction presented broad-spectrum high-efficiency photocatalytic activity towards the removal of various pollutants under visible-light irradiation, including organic dyes, antibiotics and phenols. This efficiency was linked to high light harvesting combined with effective charge separation/transfer. Meanwhile, the degradation efficiencies varied with nature of the pollutant decreased in the following order: LR5B (99%)\u202f>\u202fMNZ (97%)\u202f>\u202fTC (92%)\u202f>\u202fOTC (92%)\u202f>\u202fRhB (90%)\u202f>\u202fCIP (83%)\u202f>\u202fMB (78%)\u202f>\u202fMO (62%)\u202f>\u202fbisphenol (42%)\u202f>\u202fphenol (40%). The photocatalytic process of ciprofloxacin was explored, and the results indicated that high ciprofloxacin concentrations, low pH values and elevated concentrations of ions (PO43-, HPO42-, H2PO4-, and Cu2+) restrained the photocatalytic performances. Trapping experiments and ESR revealed the significant contribution of holes (h+) in the mechanism, where both superoxide radicals (O2-) and hydroxyl radicals (OH) acted as assistants. Overall, this work could offer a new protocol for the design of highly efficient heterostructure photocatalysts for environmental remediation.