Synthesis of BiVO4/WO3 composite film for highly efficient visible light induced photoelectrocatalytic oxidation of norfloxacin

Abstract In this study, we synthesized BiVO4/WO3 composite film via a hydrothermal method and successive ionic layer adsorption and reaction (SILAR) for photoelectrocatalytic (PEC) degradation of norfloxacin (NOR) under visible light irradiation (λ > 420 nm). The BiVO4/WO3 composite film was characterized by various techniques in details. These results suggested that BiVO4 was successfully assembled onto the WO3 film surface. The BiVO4/WO3 composite film exhibited enhanced PEC performance and the apparent rate constant for degradation of NOR was estimated to be 2.68 × 10−3 min−1, which was 3.52 and 2.39 times higher than that of WO3 and BiVO4 film, respectively. The superior PEC performance could be ascribed to the formation of n-n junction facilitating the interfacial charge transfer and separation rate, resulting in the enhanced light-harvesting capability. The generated h+, O2− and OH radicals were responsible for the PEC degradation of NOR confirmed by the radicals trapping experiments and ESR spin-trap technique. Analysis of the degradation intermediates implied that the piperazine ring of the norfloxacin was mainly attacked during the visible-light-driven degradation process.