Preparation And Characterization Of Nano Titanium Dioxide

Nano science and technology is advanced technology in the 20th and 21th century, and nanoscience enjoys a vital position in the development and progress of other sciences, industry and society. Nanoproducts have created remarkable social and economic returns. Nano science and technology will make the industrial revolution again, which be a new landmark in the distory of development of mankind's technology. Nano titanium dioxide material is very important inorganic material. Nano titanium dioxide is a catalyst. Due to its safety, nonpoisonous side effect, excellent performance, low cost, no secondary pollution,et al, Nano titanium dioxide has been found wide application in the photocatalysis. But photocatalytic activity of Nano titanium dioxide has been restricted,because of electron-hole pair compositing very much and its low utilization for the sun. Overcoming weaknesses of nano titanium dioxide and improving its photocatalytic activity is the sum total content of thesis. Nano titanium dioxide modification by many ways,such as:doped-noble metals; doped-non-metallic elements; doped-transition metals; surface treatment and so on. The thesis improves mainly photocatalytic activity of nano titanium dioxide by doping-Ag and doping-Pd. The photocatalytic activity was tested with congo red dye as the objective decomposition matter. The experiments showed that the TiO2 nanoparticles doped with silver present higher photocatalytic activity than that of pure TiO2, and the optimum molar fraction of Ag in Ag-TiO2 is 3%. Primary Contents of the thesis are as follows:Firstly, pure TiO2 has been prepared by the sol-gel process,and the pure TiO2 is been treated by 5 M NaOH. It has been characterized by XRD, FT-IR, HRTEM and SEM techniques, respectively.Secondly, TiO2 nanoparticles with various amounts of silver have been prepared by the sol-gel process, and Ag in Ag-TiO2 is 3% preparing by sol-gel hydrothermal using tetrabutyl titanate and silver nitrate as raw materials. They have been characterized by XRD, SEM, HRTEMand FT-IR techniques, respectively. XRD results showed that both the pure TiO2 and Ag-TiO2 nanoparticles were tetragonal anatase phase and the average particle size is in the range of 6～9 nm. It would inhibit the increase of the crystallite size and the phase transformation from the anatase to rutile after TiO2 nanoparticles were doped with the appropriate silver. The photocatalytic activity was tested with congo red dye, Methylene blue, Rhodamine-B and Methyl orange, as the objective decomposition matter which was studied photocatalytic activity of the products; antibacterial experiments were carried on Escherichia coli, Staphylococcus aureus and Bacillus subtilis; by the TAM Air system, the thermal power-time curves of growth and metabolism of the colibacillus determined, the growth rate constant obtained, the relationship between the inhibitory concentration and the growth rate constant ensured, then optimal concentration obtained. The experiments showed that the TiO2 nanoparticles doped with silver present higher photocatalytic activity and bacteria restreint than that of pure TiO2, and the optimum molar fraction of Ag in Ag-TiO2 is 3%. The experiments showed that TiO2 nanoparticles could improve effectively photocatalytic activity after doping with the appropriate silver.Thirdly, TiO2 nanoparticles with various amounts of palladium have been prepared by the sol-gel process using tetrabutyl titanate and palladium The experiments showed that the TiO2 nanoparticles doped with palladium present higher photocatalytic activity and bacteria restreint than that of pure TiO2, and the optimum molar fraction of Pd in Pd-TiO2 is 3%, which are in agreement with the literatures.Fourthly, TiO2 nanotube had been prepared by the hydrothermal process, and had been characterized by HRTEM, TEM, XRD, and FT-IR techniques, respectively. TEM results showed that the tip of TiO2 nanotube was needle-like.The antibacterial experiments showd that TiO2 nanotube had lower antibacterial activity than TiO2 nanoparticles.At last, it gave a brief summary of this thesis and the outlook of nanotechnology future development.