Tio <sub> 2 </ Sub> Nanocrystalline Films And Nano-crystalline Microspheres Preparation And Active Research

Because of the nanometer TiO₂'s merits such as innocuity, cheapness, stabilization of chemistry and light, using sun's rays etc. It is being more and more regarded by researchers. Although nanometer TiO₂ can remove most of the organic contamination and heavy metal ions in the system of waste water, the problems of deactivation and regeneration are restricting its application in practice. On the foundation of domestic and foreign researchers, in this paper, we studied the preparation, modification and estimate the photoactalyst's activity through the degradation reaction of methylene blue, and tried to solve the problems exist in the domain of photocatalysis. The work we did and the main conclusion we gained are following:1. Different metal ions doped and different layers of nanocrystals TiO₂ films are prepared through sol-gel method. Through calcined at 500℃, the types of these films are all anatase. When the layer is two, the photocatalytic degradation ratio of the film is the highest. When different metal ions doped in the film, the crystal degree of the TiO₂ films changed. The photocatalyst doped with La³⁺ has the highest degradation ratio. The optimal doped amount of La³⁺ is 0.6%, the degradation ratio of methylene blue almost arrived 92%.2. TiO₂ microspheres are synthesized through sol-gel electrolyte method by adding a little of inorganic salt electrolyte, the effect of the concentration and the kind of the electrolyte on the size of the microspheres is studied. The result indicated that the size of the microspheres can be controlled, the concentration and kinds of the electrolyte, especilly the kinds of cation can affect the size of the microspheres greatly. The surface, crystalline structure, hole structure and aperture distribution of the microspheres synthesized were characterized by various methods, such as TEM, SEM, UV-VIS, XRD TG-DTA ,BET and nitrogen-adsorption etc. The result showed that the microspheres are made up of amount of TiO₂ nanocrystals with its size about 15nm. The photocatalytic degradation ratio of the microspheres are higher. In addition, microspheres are also synthesized by sol-gel surfactant method. We study the variety of microspheres' size with the changing of the synthesis condition. The mechanism of this method is primary interpreted. Photocatalytic experiment showed that the microspheres' photodegradation activity on methylene blue solution...