Preparation, Characterization And Photoactivity Of The Anatase TiO₂ Exhibit High Surface Energy

Nano TiO2 has high photocatalytic activity, good stability, non-toxic, inexpensive, and many other advantages as photocatalysis research priorities. High-energy surface of TiO2 photocatalytic shows broad application prospects, because of the characteristics of the high photocatalyst activity. The surface scientists have demonstrated that the order of the average surface energies of anatase TiO2 isγ{110} (1.09 J/m2)>γ{001} (0.90 J/m2)>γ{100} (0.53 J/m2)>γ{101} (0.44 J/m2). Theoretical and experimental studies on the photocatalytic activity of anatase TiO2 showed that the{001} facets are much more reactive than the{101} facets. Thus, it has been an important research goal to find a synthetic method to synthesize anatase TiO2 with high percentage of{001} facets. In general, it is difficult to prepare inorganic single crystals with highly reactive surfaces, because the crystal growing quickly diminishes such surfaces to minimize. the surface energy. It is desirable to develop a new functional material with dominant{001} facets that offers good photocatalytic activity.In Chapter 2 of this thesis, anatase TiO2 catalysts with different morphology and high surface energy exposed{001} have been prepared at low temperature with Liquid Precipitation method. The samples were characterized by XRD,SEM,TEM,UV-Vis diffuse reflectance spectra, and XPS methods. The different morphology and exposed {001} facets of anatase TiO2 powders have been successfully controlled by simply changing the concentration of PrOH. The proposed mechanism that the presence of PrOH influences the formation of the exposed{001}anatase TiO2 is discussed. BF4-prefers to adsorb on the{001} surface, which is related to the higher reactivity of the {001}. The addition of PrOH can strengthen the stabilization effect associated with fluorine adsorption and thus stimulate the growth of the{001} surface. Though it don't have a high surface area, this anatase TiO2 exposed{001}exhibit a good photoactivity.In Chapter 3 of this thesis, the anatase TiO2 exposed{110} and{001} catalyst has been prepared with hydrothermal method. Au/TiO2 catalyst was prepared by deposition-precipitation methods. The sample was characterized by XRD, SEM, UV-Vis diffuse reflectance spectra, TEM methods. We investigate the system by adding different amount of HF, there yield different morphology and photoactivity of anatase ToO2 when adding different amount of HF. The photoactivity of the sample was tested for the photodegradation of rhodamine B. The results showed that the sample of anatase TiO2 exposed both{110} and{001} exhibit high photoactivty. Au/TiO2 catalyst was prepared by deposition-precipitation method. Anatase TiO2 loading Au also exhibit higher photoactivity.