Preparation And Photocatalytic Properties Of ZnO/RGO Composites

Zinc oxide (ZnO), a wide-band gap semiconductor, can be used in the field of photocatalysis. The main factors that affect its photocatalytic activity are the narrow light response range and rapid recombination of photo-generated electron-hole pairs. Reduced graphene oxide (RGO), a monolayer of carbon atoms packed honeycomb crystal structure. Due to the unique nanostructure and extrodinary electronic properties, RGO plays an important role in the aspect of modified ZnO materials. The main contents are as follows:1. Sythensis and characterization of RGO and graphene oxide (GO):GO was obtained by oxidation of graphite powders by the modified Hummers’ method. GO was reduced by sodium borohydride in order to get RGO. Thermogravimetry (TG), X-ray diffraction (XRD), fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and morphology of GO and RGO. The results showed that we obtained GO powers in high quality which is rich in organic groups, the RGO possess thin layer structure with large specific surface area, and the organic groups were stripped after the reducing reaction. We also found out that graphene has no photocatalytic properties to methylene blue.2. Synthesis and photocatalytic propertis of ZnO/RGO:The fabrication of amorphous morphology ZnO particles in ethanol solution which with different molar ratios between Zn2+and OH-, the ZnO photocatalysts with different size and morphology were obtained after calcination under500℃. ZnO/Reduced Graphene Oxide (RGO) composites were synthesized by a facile hydrothermal method. The crystal structure and morphology of ZnO nanoparticles and ZnO/RGO nanocomposites were characterized by XRD, FT-IR and SEM. The composite photocatalytsts showed a significant enhancement in photocatalytic property in comparision to pure ZnO as demonstrated in photodegradation of methylene blue.3. Preparation and photocatalytic properties of N-ZnO/RGO:N-doped ZnO was synthesied by wet chemistry with urea as the source of nitrogen. Different weight ratio GO colloids and N-ZnO particles were mixed by solution mixing method, and N-ZnO/RGO photocatalysts were obtained by the following hydrothermal treatment. The as-prepared samples were characterized by XRD, FT-IR, EDS and SEM. The photocatalytic degradation of methylene blue using bare ZnO and N-ZnO/RGO composites were studied. The results showed that the N-ZnO and the composite photocatalysts all exhibited better photocatalytic property than bare ZnO.