Efficient Photocatalytic Degradation of Tetracycline by S‐Type Heterojunction BiOBr/h‐MoO₃ With Oxygen‐Rich Vacancies Under Visible Light

ABSTRACT A BiOBr/h‐MoO 3 heterostructure photocatalyst with oxygen vacancy (OV) modulation was synthesized via solvothermal in situ precipitation, exhibiting enhanced visible‐light‐driven tetracycline (TC) degradation performance. The composite demonstrated 1.5‐ and 4‐fold higher TC degradation rates compared to pristine BiOBr and h‐MoO 3 , respectively. Structural characterization via XRD, XPS, and FTIR confirmed the successful synthesis of the composite with controlled OV concentration and interfacial bonding characteristics. Photoluminescence (PL) and electron spin resonance (ESR) analyses revealed that the BiOBr/h‐MoO 3 heterojunction achieved optimal reactive oxygen species (ROS) production and minimized electron–hole recombination. Under optimized conditions (catalyst dosage: 10 mg L −1 , TC concentration: 10 mg L −1 , pH 10), the system attained 84% TC degradation within 60 min while maintaining 80% efficiency after five operational cycles. Mechanistic studies identified hydroxyl radicals (OH) and photogenerated holes (h + ) as dominant active species, with OVs critically enhancing interfacial charge transfer efficiency. This work provides a viable strategy for constructing OV‐engineered heterojunction photocatalysts for antibiotic wastewater treatment.