Cui Zhengwei

Hydrothermal Synthesis and Photocatalytic Activity of Partially Reduced Graphene Oxide/TiO 2 Composite

Partially reduced graphene oxide/titanium dioxide (RGO/TiO 2 ) composite was synthesized using tetrabutyl titanate and graphite oxide by a hydrothermal method. Photocatalytic activity of the material was evaluated by the degradation of methylene blue solution under visible light and UV light. The results suggest that the crystal phase and dispersion of titanium oxide in the composite can be controlled by varying the reaction temperature and amount of graphite oxide. Graphene oxide was partially reduced in the hydrothermal reaction process. Photocatalytic activities of partially reduced graphene oxide/titanium dioxide composites under both visible and UV light irradiation were higher than those of pure TiO 2 . Partially reduced graphene oxide may act as a support and electron acceptor, and can also extend and enhance the band edge absorption of TiO 2 into the visible light region, hence effectively enhancing the adsorbability and photocatalytic activity of TiO 2 .

Preparation and Visible Light Photocatalytic Activity of Titanium Dioxide Coated Multiwalled Carbon Nanotubes

Titanium dioxide coated multiwalled carbon nanotubes (MWCNTs) composite photocatalysts were prepared by the controllable oxidation of titanium carbide coated MWCNTs obtained by the molten salt method using MWCNTs as a reaction template and metal titanium powder as a titanium source. The effects of the molten salt reaction temperature, the molar ratio of MWCNTs to titanium powder, and the oxidation temperature on the structure and morphology of the products were investigated. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The photodegra- dation of a methylene blue (MB) solution was used to evaluate the photocatalytic activity of the catalyst under visible light irradiation (λ420 nm). The results suggest that the TiO2 coated MWCNTs keep the similar fibred morphology with the pristine MWCNTs. Uniform and fine well-dispersed TiO2 coatings on the surface of MWCNTs closely contact with the MWCNTs support and Ti-O-C chemical bonds form between them. The prepared TiO2/MWCNTs photocatalyst shows higher visible light photocatalytic activity because the MWCNTs increase the adsorption of methylene blue on the photocatalyst and an impurity state is formed close to the valence band of titanium dioxide, which can enhance the absorption and utilization of solar energy.

Preparation and Structure Regulation of Silicon Carbide-Derived Carbon/ Spherical Natural Graphite Composites

To meet the requirements of the energy storage materials for high energy density and high power density, porous silicon carbide/derived carbon-spherical natural graphite (SiC-CDCs@NG) composites were prepared. The composites were composed of tailored porous carbide-derived carbon and graphitized carbon with excellent conductivity and a high energy storage capacity. The composition, structure, morphology, pore structure, and specific surface area of the composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and N2 adsorption/ desorption analysis. The composites exhibited a high and adjustable specific surface area and micro-pore volume, with a micro-pore size of between 0.5 and 0.7 nm. Varying the molar ratio of NG and Si allowed optimization of the micro-pore volume, pore size distribution, specific surface area, and composition and content of the CDCs shell and NG core.