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

• The novel Bi 4 O 5 Br 2 /MIL-88B(Fe) composites were fabricated via a two-step method. • BMF showed excellent 93.04% removal efficiency on TCH degradation. • Z-scheme system formed internal electric field and enhanced the oxidation capacity. • EPR tests and scavenger experiments confirmed the main radicals of ·O 2 - . • The photocatalytic degradation mechanism was elucidated. Bi 4 O 5 Br 2 /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 Bi 4 O 5 Br 2 /MIL-88B(Fe) heterojunction simultaneously contributed to improved catalytic performance. Meanwhile, Z-scheme Bi 4 O 5 Br 2 /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 Bi 4 O 5 Br 2 (t = 0.95 ns). Furthermore, following operating conditions, such as pH, solution concentration, various ionic species, etc., the Bi 4 O 5 Br 2 /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.