Preparation And Performance Study On F-doped And Composite TiO₂ Photocatalyst

TiO₂-based semiconductor photocatalysis technology has been shown to be potentially advantageous for environmental remediation as it may lead to complete mineralization of pollutants at ambient conditions with the use of ultraviolet light as the energy source. However, the large scale application of titanium dioxide as mutual photocatalyst is hampered by the fact that it absorbs only the very small ultraviolet part of solar light due to its wide band-gap of 3.2eV. In order to further enhance its activity, this research used the doping method to modify TiO₂ on the basis of of the inveatigation of TiO₂ photochemical mechanism. For convenient, Rhodamine B (RB) solution was degradated. The photocatalytic degradation of the organic pollutant was studied with nanometer TiO₂ and the production after modification. The main results are as following:(1)F- doping was used to modify TiO₂ on the basis of the study on TiO₂ photochemical mechanism. Nanometer TiO₂ and F-TiO₂ were prepared Ti (OC4H9)4 with TiCl₄ as the source of titanium, and HF as dopant. The influence of the hydrothermal temperature and the dosage of HF on crystal composition and particle size, as well as the photocatalytic performance of the production were studied. It shows that the production after doping are all anatase phase with high photocatalytic activity. The higher of the hydrothermal temperature and the smaller of the dosage of HF, the bigger the particle size becomes.(2)Magnetic Fe₃O₄ powder was prepared and used as the core. Then nano-sized SiO₂ and TiO₂ were deposited onto the surface of Fe₃O₄. After treatment at 500℃, the low-density magnetic micro-nano-photocatalyst TiO₂/SiO₂/Fe₃O₄ was obtained. Its structure was characterized by XRD, TG-DTA, and other analysis methods. The new photocatalyst had excellent absorption and photocatalytic activity for RB solution with a wide application potential.(3)Carbonization of glucose leaded to the formation of monodispersed carbonaceous polysaccharide microspheres. These carbon spheres had strong selective absorption activity of formaldehyde. Then TiO₂ was loaded onto the prepared microspheres, forming the photocatalytic substance TiO₂/C. Furthermore, Fe₃O₄/C was prepared using one-step hydrothermal method, and was doped with TiO₂. Then a kind of catalyst which can be recycled by maganetic force was obtained.