The performance of daylight photocatalytic activity towards degradation of MB by the flower-like and approximate flower-like complexes of graphene with ZnO and Cerium doped ZnO

Semiconductor photocatalysts have played an important role in degrading water pollution in recent years. In this paper, the effects of graphene on the structure, morphology, optical properties and photocatalytic activity of ZnO and Ce-doped ZnO were studied. The photocatalysts of ZnO, Ce doped ZnO (ZnCeO), ZnO-Graphene (ZG), Ce doped ZnO-Graphene (ZGCeO) were synthesized via one-step hydrothermal method and were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), ultraviolet visible absorption (UV-vis). The results of XRD show the synthesized samples were all ZnO phases without impurity peaks. The prepared ZnO was hexagonal wurtzite crystal structure. A flower-like ZG and an approximate flower-like ZGCeO were characterized via SEM. The UV-vis spectra shows that the absorption edges have red-shifts and the absorption band broaden in all doped or composite samples, meanwhile, the band gap energy decreased from 3.26 eV to 3.06 eV. In addition, compared with pure ZnO, the photocatalytic activity of ZnCeO, ZG and ZGCeO are improved. Among them, ZGCeO shows superior photocatalytic activity: the degradation rate of organic dye MB was 99.17 % in 90 min under simulated solar irradiation.