Oxygen vacancy modulation S-scheme heterojunction mesoporous BiOBr-CoPc photocatalytic degradation of ofloxacin

Designing high-performance photocatalysts to achieve efficient degradation of antibiotics by promoting the rapid migration of photogenerated electrons and optimizing surface reaction kinetics has become a research hotspot in the environmental field. Here, mesoporous BiOBr (MBiOBr) was successfully prepared by a chelating ion exchange strategy combined with the hydrothermal method, and CoPc was further introduced through wet treatment to construct the MBiOBr-CoPc heterojunction. MBiOBr-CoPc exhibited excellent photocatalytic degradation of ofloxacin (OFL). The degradation efficiency was as high as 91 % within 16 min, which was 10.3 times that of BiOBr. In addition, the degradation performance of MBiOBr-CoPc was investigated under different OFL concentrations, pH values, water qualities, and anions. It was proved that MBiOBr-CoPc has a wide range of environmental adaptability. Theoretical calculations and experimental results show that the exceptional performance of MBiOBr-CoPc is because of the abundant oxygen vacancies generated by MBiOBr in the lattice mismatch-induced mesoporous formation process. The presence of oxygen vacancies not only strengthens the electric field effect of the heterojunction interface, but also induces the formation of impurity bands, which can serve as a bridge for electron transfer and promote electron migration. This study provides a useful reference for exploring the mechanism of performance improvement of mesoporous two-dimensional materials in heterojunctions.