In situ synthesis of S-scheme AgBr/BiOBr for efficient degradation of sulfonamide antibiotics: Synergistic effects of oxygen vacancies and heterojunctions promote exciton dissociation

The Coulomb force of photogenerated electrons and holes induces exciton effects during the process of photocatalysis, which limits the performance of semiconductors in this regard, whereas the conversion of photocatalytic excitons to free carriers serves a key role in photocatalytic processes. Herein, an AgBr/BiOBr S-scheme heterojunction composite material with surface oxygen vacancies was synthesized by in situ hydrothermal method for the degradation of sulfonamide antibiotics. It was confirmed that the kinetic rate constant (Kobs) for sulfisoxazole was 0.3199 min−1 under 15 min exposure to visible light, which was 72.7 and 52.4 times that of BiOBr (0.0044 min−1) and AgBr (0.0061 min−1), respectively. Significantly, the photoluminescence (PL) detection and experimental trapping detection verified that the introduction of oxygen vacancies (OV) and S-scheme heterojunctions enhanced exciton dissociation and carrier transfer, which facilitated the generation of reactive oxygen species (ROS). Therefore, the AgBr/BiOBr-OV offers an innovative vision for the creation of a synergistic S-scheme heterojunction and oxygen vacancy photocatalytic system for the efficient utilization of solar light and provides a promising solution for the remediation of contaminated water.