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

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%) > MNZ (97%) > TC (92%) > OTC (92%) > RhB (90%) > CIP (83%) > MB (78%) > MO (62%) > bisphenol (42%) > phenol (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.