A novel ZnO/Fe³⁺-doped Bi₂WO₆ photocatalyst with triple synergistic effect for solar-driven tetracycline degradation

To address the limited visible-light absorption and rapid charge recombination of Bi₂WO₆ photocatalysts, this work constructs a Z-scheme ZnO/Fe³⁺-doped Bi₂WO₆ heterojunction via a hydrothermal-calcination method. The Fe³⁺ doping induces the formation of oxygen vacancies and optimizes the band structure, which cooperates with the interface reconstruction of ZnO to expand the light absorption to 480 nm. The hierarchical pore structure simultaneously enhances the mass transfer efficiency, and finally realizes the efficient degradation of tetracycline under visible light (the removal rate is 95.5% in 60 minutes, and the rate is 2.28 times higher than that of the pure phase) and the stable cycle performance is good. Mechanistic studies demonstrate that Z-scheme charge transfer driven by an interfacial built-in electric field ensures effective carrier separation, with photogenerated holes (h⁺) as key reactive species. The proposed "defect-heterojunction-interface trinity" strategy establishes a new design scheme for bismuth-based Z-scheme photocatalysts.