Microwave-assisted synthesis of ZnO-graphene composite for photocatalytic reduction of Cr(VI)

ZnO-graphene composites are successfully synthesized via microwave-assisted reaction of zinc sulfate in aqueous solution with a graphite oxide dispersion using a microwave synthesis system. Their morphology, structure and photocatalytic performance in reduction of Cr(VI) are characterized by scanning electron microscopy, X-ray diffraction spectroscopy and UV-vis absorption spectrophotometer, respectively. The results show that in the composite the graphene nanosheets are decorated densely by ZnO nanosheets, which display a good combination between graphene and ZnO nanosheets. The ZnO-graphene composite exhibits an enhanced photocatalytic performance in the reduction of Cr(VI) with a removal rate of 98% under UV light irradiation as compared with pure ZnO (58%) due to the increased light absorption intensity and range, as well as the reduction of electron-hole pair recombination with the introduction of graphene.