Facile construction of hierarchical flower-like Z-scheme AgBr/Bi2WO6 photocatalysts for effective removal of tetracycline: Degradation pathways and mechanism

A novel hierarchical flower-like AgBr/Bi2WO6 Z-scheme photocatalyst was prepared through the simplified hydrothermal and deposition-precipitation method. The as-prepared photocatalysts exhibited excellent photocatalytic performance for tetracycline (TC) degradation. Especially, AgBr (20 wt%)/Bi2WO6 displayed the optimal TC removal efficiency (87.5%) within 60 min of visible light illumination. Besides, no obvious decrease in photocatalytic performance was observed after four cycles. The excellent photocatalytic performance could be ascribed to the synergistic effect between electron mediator Ag nanoparticles (Ag NPs) and Z-scheme heterojunction charge transfer mechanism, which enhanced the light harvest capability, separation efficiency of photo-generated carriers and redox ability. Moreover, three-dimensional excitation-emission matrix fluorescence spectroscopy (3D EEMs) and liquid chromatography-mass spectrometry (LC-MS) analyses shed light on the mineralization behavior and the detailed decomposition pathway of TC. This work opened up a new road to efficient Z-scheme heterojunction design and provided novel insights into antibiotics elimination mechanism in photocatalysis.