Preparation And Photocatalytic Properties Of Multi-morphological TiO₂/graphene Composite Powders

TiO₂ as a kind of environmental-friendly and cheap semiconductor material is of great prospective value in the applications of organic pollutants in water and air purification. Considering the technique issues of TiO₂, such as small specific surface area, seviou particle agglomeration, and high recombination rate of electron-hole pair, we aim at preparation of multi-morphological structured TiO₂/graphene composite catalysts to improve the photocatalytic performance.Graphite oxide?GO? was prepared by improved Hummers method with natural graphite flakes. The obtained GO and TiO₂ nanoparticles?P25? as raw materials were used to prepare multi-morphological structured TiO₂/graphene composite powders by hydrothermal and solvothermal methods in combination with sintering process. The composite powders were characterized by means of X-ray diffraction?XRD?, Transmission electron microscopy?TEM?, Scanning microscopy?SEM?, Raman spectrum?Raman?, Fourier transform infrared spectroscopy?FT-IR?, Specific surface area?BET?, UV-Vis diffuser reflectance?UV-Vis DRS?. The photocatalytic properties of TiO₂/graphene composites were studied by using methylene blue?MB? as a target pollutant. The factors were discussed on their effects of photocatalytic properties. The photocatalytic mechanism was proposed.The following results were obtained.?1? TiO₂ particles were successfully loaded on the surface of graphene by hydrothermal and solvothermal methods.The multi-morphological structure of TiO₂?such as nano-wire, nano-rod, nanoplane, nano-ribbon? could be obtained by controlling hydrothermal temperature,solvent ratio, and dosage of Na OH.?2? The photocatalytic properties of TiO₂/graphene composites were influenced by the dosage of graphene and the morphological structure of TiO₂. High photocatalytic efficiency was realized at the 1:3 ratio of TiO₂ nanowire/graphene and nano-rod morphology of TiO₂.?3?The photocatalytic mechanism was found to be related with the absorption properties of composite powders and the synergistic effect between graphene and TiO₂. The composite powders of TiO₂ nano-rod and graphene prepared at hydrothermal temperature of 180 ?, the Na OH concentration of 1.73 mol/L, the H2O/C2H5 OH volume ratio of 15:50 were found of good photocatalytic performance as high as 90 %.