Excellent photocatalytic reduction of nitroarenes to aminoarenes by BiVO4 nanoparticles grafted on reduced graphene oxide (rGO/BiVO4)

A novel heterogeneous composite material based on reduced graphene oxide (rGO) and bismuth vanadate (BiVO4) was prepared and characterized by various techniques such as powder XRD, HRTEM, EADX, UV-Vis-DRS, FT-IR, Raman, BET and XPS analyses. The characterization results reveal that the rGO well decorated by BiVO4. The electrochemical impedance spectroscopy (EIS) shows the increasing of charge transfer of rGO/BiVO4 in presence of light irradiation. In this research, the pure BiVO4 and rGO/BiVO4 composite have been explored for photocatalytic reduction of nitroarenes. Among the prepared nanocomposites, rGO loaded with 10% BiVO4 catalyst (noted as rGO/BiVO4-10%) shows the best performance for the photo-reduction of various nitroaromatic molecules to their corresponding amine compounds under visible-light irradiation at room temperature. The catalyst exhibited in particular excellent photocatalytic activity for the conversion of 1,4-dinitrobenzene to 4-nitroanilline (100% conversion) in 20 min, 4-chloronitrobenzene to 4-chloroaniline and 2-nitrophenol to 2-aminophenol (100% conversion) in only 30 min. In addition, the conversion of 4-bromonitrobenzene, 4-iodonitrobenzene to their corresponding amine compounds (100% conversion) was achieved in 60 min. The catalyst was recovered for several times and reused without decreasing of its efficiency.