Z-scheme Bi₄O₅Br₂/MIL-88B(Fe) heterojunction for boosting visible light catalytic oxidation of tetracycline hydrochloride

Bi₄O₅Br₂/MIL-88B(Fe) Z-scheme heterojunction photocatalyst is fabricated by a facile hydrothermal followed by a coprecipitation method. The heterojunction catalyst greatly improved the visible light utilization and has shown excellent photodegradation performance for tetracycline hydrochloride (TCH). The high oxidation capability, unique charge migration, and enhanced photogenerated charge carrier separation of Z-scheme Bi₄O₅Br₂/MIL-88B(Fe) heterojunction simultaneously contributed to improved catalytic performance. Meanwhile, Z-scheme Bi₄O₅Br₂/MIL-88B(Fe) heterojunction has achieved the highest photodegradation of TCH with ∼93.04 % within 80 min. In addition, the time-resolved photoluminescence (PL) emission decay spectra confirmed a prolonged lifetime of electron excitation with a fluorescence lifetime of ∼1.08 ns compared with Bi₄O₅Br₂ (t = 0.95 ns). Furthermore, following operating conditions, such as pH, solution concentration, various ionic species, etc., the Bi₄O₅Br₂/MIL-88B(Fe) heterojunction has shown excellent photodegradation of TCH in various environmental conditions with high photostability. Additionally, a substantial charge transfer mechanism and TCH photodegradation pathway were explained. This work demonstrates a promising approach to constructing other high-efficiency Z-scheme heterojunction materials for wastewater treatments.