Solvothermal Synthesis of Cu-Bi4O5Br2 Photocatalyst Enhanced Visible Light Degradation of Ciprofloxacin

Cu-doped Bi4O5Br2 photocatalyst was synthesized via a solvothermal method, and the influence of Cu doping on its structure, morphology, and photoelectric characteristics was comprehensively investigated by adopting various characterization techniques. Furthermore, the photocatalytic performance of the material was assessed through the degradation of ciprofloxacin (CIP) under visible light. The characterization results demonstrated that compared to the intrinsic Bi4O5Br2, the introduction of Cu resulted in a decreased bandgap, an expanded visible light absorption range, an enhanced visible light absorption intensity, and improved separation efficiency of electrons and holes, thereby enhancing the photocatalytic activity. In the ciprofloxacin degradation experiment, 3%Cu-Bi4O5Br2 exhibited superior performance, achieving a degradation rate of 80.1%, which was more than twice as high as the intrinsic Bi4O5Br2 (53.2%). Moreover, it maintained excellent stability even after undergoing five cycling experiments. The free radical capture experiments indicated that h(+), center dot O-2(-) and center dot OH played a dominant role in the photodegradation reactions of ciprofloxacin. Finally, this study discussed the possible photocatalytic mechanism and deduced three degradation pathways of ciprofloxacin on the basis of the 8 intermediate products detected by LCMS. In summary, Cu-Bi4O5Br2 demonstrated remarkable photocatalytic performance and stability under visible light response, positioning it as a promising catalyst for future sunlight-based removal of diverse pollutants.