Green and efficient photodegradation of norfloxacin with CsPbBr3-rGO/Bi2WO6 S-scheme heterojunction photocatalyst

Modern chemistry aims to identify excellent photocatalyst for pollution challenge associated with the antibiotics-containing wastewater. In this contribution, a novel CsPbBr3-rGO/Bi2WO6 S-scheme heterojunction with superior stability and excellent photocatalytic activity was achieved via trimercaptopropionic acid (MPA) modification for norfloxacin photodegradation. Here, MPA acted not only as an organic ligand to stable the composite by formation of strong -SH-Pb- bond and -COO-Bi-O- bond, but also worked as an electronic bridge to transfer and separate photogenerated carriers. The CsPbBr3-rGO/Bi2WO6 composite displayed the excellent photocatalytic activity compare with pure Bi2WO6 and rGO/Bi2WO6, and the norfloxacin degradation rate was about 66.79% with 120 min under visible light irradiation. The results of the UV-Vis diffuse reflectance spectra, PL spectra, transient photocurrent response, and reactive-species-trapping experiments indicated that the expanding light-harvesting scope, efficient charge separation ability, and large amounts of active species, are the major reasons for the enhancement photocatalytic activity of CsPbBr3-rGO/Bi2WO6 composite. According to the cycle experiment, the photodegradation rate of norfloxacin is no significant decrease, the XRD pattern and FTIR spectra before and after norfloxacin degradation displayed almost no change, indicating the superior stability of the CsPbBr3-rGO/Bi2WO6 composite. This work not only provides a new opportunity to strengthen the stability and charger-transfer efficiency of CsPbBr3 nanocrystals (NCs), but also opens up a new insight for photocatalytic application of CsPbBr3 NCs.