rGO/Bi₂WO₆ composite as a highly efficient and stable visible-light photocatalyst for norfloxacin degradation in aqueous environment

Fabrication of binary composite has proved to be an efficient approach to improve the photocatalytic activity of monomer photocatalyst. In this contribution, an effective Reduced Graphene Oxide/Bismuth Tungsten Oxide (rGO/Bi₂WO₆) composite with outstanding photocatalytic activity was designed by employing Bi₂WO₆ as a primary photocatalyst and rGO as an electron acceptor and transporter for norfloxacin degradation in aquatic environment. The rGO/Bi₂WO₆ composite displayed higher photocatalytic activity compare with pure Bi₂WO₆, which could degrade about 87.49% of norfloxacin with 180 min under visible light irradiation. The results of the UV-vis diffuse reflection spectrum, photoluminescence spectra and transient photocurrent response implied that the enhanced photocatalytic activity of the rGO/Bi₂WO₆ composite could be attributed to the improved visible light-harvesting ability and the efficient charge separation ability. Additionally, the reactive-species-trapping experiments indicated that ⋅OH and e^- played dominant roles during the photocatalytic degradation process. Four possible intermediates and two possible transformation pathways of norfloxacin degradation were detected by LC-MS. This present work provided a low-cost and facile green method to design of Bi-based composite.