Promoting tetracycline degradation via synergistic effects of BiOBr/TiO2/NH2-UiO-66 ternary Z-scheme heterojunctions under visible light irradiation

A ternary Z-scheme heterojunction photocatalyst, BiOBr/TiO 2 /NH 2 -UiO-66(Zr), was constructed to enhance the visible-light-driven degradation of tetracycline (TC). This composite material was synthesized via hydrothermal and in situ growth methods, and its microstructure and properties were analyzed through a series of systematic characterizations. The introduction of NH 2 -UiO-66 significantly increased the specific surface area and visible light absorption while promoting the separation and transport of photogenerated charge carriers. Under visible light irradiation, the optimal composite (BTU-2) achieved a TC degradation rate of 96.3% within 80 min, with a reaction rate constant 9.41, 12.03, and 8.58 times higher than those of pure BiOBr, TiO 2 nanowires (NWs), and NH 2 -UiO-66, respectively. Trapping experiments and electron paramagnetic resonance (EPR) analysis confirmed that h + and ‧O 2 − were the dominant active species. Liquid chromatography–mass spectrometry (LC–MS) further elucidated the possible TC degradation pathways. This work provides a feasible strategy for designing efficient visible-light-responsive photocatalysts for antibiotic wastewater treatment. Graphical abstract