Construction of CdSe quantum dots/SrBi4Ti4O15 Z-scheme heterojunction for enhanced photocatalytic degradation of tetracycline

Residual antibiotics in aquatic environments pose significant ecological challenges. Photocatalytic oxidation technology is highly effective in eliminating these contaminants. The layered perovskite semiconductor SrBi 4 Ti 4 O 15 (SBTO) exhibits exceptional photocatalytic potential due to its stability and robust oxidative capacity. However, its wide bandgap and rapid recombination of photogenerated carriers limit its efficiency. To address these limitations, we developed a CdSe quantum dot/SrBi 4 Ti 4 O 15 (CS/SBTO) composite. The results show that CdSe quantum dots are uniformly distributed on SBTO nanosheets, increasing the specific surface area and extending visible light absorption. The formed Z-scheme heterojunction significantly enhances photocatalytic degradation efficiency, achieving a degradation rate 6.5 times higher than that of SBTO alone. Radical trapping experiments indicate the involvement of holes, hydroxyl radicals, and superoxide radicals in the reaction. Cycling tests demonstrate the composite's good stability. The degradation pathway was elucidated based on intermediates detected by HPLC-MS. This study provides a foundational basis for developing efficient photocatalytic water purification technologies.