Preparation And Characterization Of Nano Composite Photocatalyst With High Visible Light Photocatalytic Activity

Compared with other oxide semiconductor photocatalysts such as nanometer CdS, ZnS, PbS, SnO2, MoO3, ZnO, V2O5, WO3 and so on, nanometer TiO2 photocatalyst has become the most interested focus of people for its many advantages. But nanometer TiO2 belongs to the oxide semiconductor with wide band gaps, it can only absorb UV in sunlight, which greatly limits its practical application in organic pollutants under the visible part. In this paper, W-doped TiO2 photocatalysts and W-doped TiO2/C60/MWCNTs composite photocatalysts with high visible light photocatalytic activity were synthesized by a simple hydrothermal method. This way is focused on the modification of nanometer TiO2 by W-doping, composite heterozygous with multi-walled carbon nanotubes (MWCNTs) and fullerenes. It can effectively regulate and control the band structure of photocatalyst materials, reduce the bandgap and strengthen the visible response using the good conductivity and adsorption ability of MWCNTs and the unique electronic and optical properties of fullerenes. It is expected that W-doped TiO2 photocatalysts and W-doped TiO2/C60/MWCNTs composite photocatalysts are widely applied.In chapter 2, the main point is exploring the influences of W-doped on photocatalytic activity of nanometer TiO2, and finding the optimum doped molar percentage of W. Nano W-doped TiO2 photocatalyst was prepared by the hydrothermal method in this chapter. The change of photocatalytic activity under UV and visible light irradiation was studied by controlling the doped molar percentage of W. When the doped molar percentage of W was 40mol%, the photocatalyst had maximum absorption redshift compared with pure TiO2, and its photocatalytic activity was much higher than P25 and pure TiO2.In chapter 3, the composite heterozygous material (C60/MWCNTs) of fullerenes C60 and multi-walled carbon nanotubes (MWCNTs) was successfully prepared by a simple method. The basic principle was to realize the chemical assembly between fullerenes C60 and multi-walled carbon nanotubes (MWCNTs) by covalent bond. The method could make fullerenes C60 be wrapped on MWCNTs surface tightly, and be firmly heterozygous composite.In chapter 4, the main point is discussing the influences of MWCNTs and fullerenes C6o on the photocatalysis of TiO2 photocatalyst. Using TiCl4 as starting material, (NH4)2WO4 as the source of W, multi-walled carbon nanotubes (MWCNTs) as the carrier, and compositing with C6o/MWCNTs, the W-doped Ti02/C6o/MWCNTs composite photocatalyst was prepared finally by the hydrothermal method. This research method is to use the good conductivity and adsorption of MWCNTs and C6o, which can effectively reduce the recombination rate of electron and hole, greatly enhance the photocatalytic activity of photocatalyst.