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

Herein, an efficient broad-spectrum WS/BiOBr heterostructure with ultrathin nanosheet was successfully prepared by one-pot hydrothermal route. The self-assembled flower-like WS/BiOBr nanostructure was formed by few-layer WS 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 (PO, HPO, HPO, and Cu) restrained the photocatalytic performances. Trapping experiments and ESR revealed the significant contribution of holes (h) in the mechanism, where both superoxide radicals (O) 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.