The facile fabrication of Z-scheme Bi₂WO₆-P25 heterojunction with enhanced photodegradation of antibiotics under visible light

The construction of heterojunction photocatalyst with a simple method is of vital significance for practical application of photocatalytic technology. Herein, a novel Z-scheme Bi₂WO₆-P25 photocatalyst was successfully synthesized by a facile one-step hydrothermal method. The catalyst exhibited excellent photodegradation efficiency of tetracyclines (TCs) and fluoroquinolones (FQs) under visible light. Superior degradation capability could be ascribed to the Z-scheme heterojunction charge transfer mechanism between Bi₂WO₆ and P25. It not only provided more reactive sites for target pollutants during catalytic process, but also improved the visible-light harvesting capacity and charge separation efficiency. Mechanisms were explored through quenching and EPR experiments, it revealed that h⁺ and •O₂⁻ worked together to reach the efficient degradation rate of TC. The detailed decomposition pathways of TC were also proposed by UPLC-MS analysis. In addition, the results of major factor exploring experiments showed that the degradation efficiency of TC and CIP were significantly improved under weakly acidic and neutral conditions, while the effects of introduction of NO₃^- and SO₄^2- were negligible. In general, Bi₂WO₆-P25 Z-scheme heterojunction is proved to be a promising photocatalyst that possesses a great potential application in the treatment of antibiotic wastewater.