Investigation of photocatalytic activities over ZnO–TiO2–reduced graphene oxide composites synthesized via microwave-assisted reaction

ZnO–TiO2–reduced graphene oxide (RGO) composites were successfully synthesized by microwave-assisted reduction of graphite oxide in ZnO precursor solution with TiO2 suspension using a microwave synthesis system. Their morphology, structure, and photocatalytic performance in the reduction of Cr(VI) were characterized by scanning electron microscopy, X-ray diffraction spectroscopy, and UV–vis absorption spectrophotometer. The results show that ZnO–TiO2–RGO composites exhibit an enhanced photocatalytic performance in reduction of Cr(VI) with a maximum removal rate of 99.4% under UV light irradiation as compared with pure ZnO (58%) and ZnO–RGO (98%) composites due to the increased light absorption intensity and the reduction of electron–hole pair recombination in ZnO with the introduction of TiO2.

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► ZnO–TiO2–RGO composite is synthesized by microwave-assisted reaction.
► The photocatalytic reduction of Cr(VI) by ZnO–TiO2–RGO is investigated.
► A high Cr(VI) reduction rate of 99.4% is achieved under UV light irradiation.