| TiO2 was believed to be important photocatalyst for its good optical stability and no toxicity. But it did not facilitate to widespread due to deficiencies such as large band gap and weak photocatalytic activity. So it was important to research and develop the high activity photocatalyst.In this paper, we synthesized the high activity nanometer TiO2 through hydrothermal / solvothermal reaction. The main results were as following:Titania nanocrystals were prepared by a hydrothermal process in liquid media, the crystallization of amorphous precursor could proceed at low temperature around room temperature. The phase composition, microstructure, morphology, and specific surface area of titania changed significantly depending on there precipitation temperatures. Well-crystallized Rod-like nanosize rutile crystals possessed higher photocatalytic activities than those of anatase crystals radiation with mercury lamp.A solvothermal synthetic method to TiO2 nanoparticles has been investigated in toluene solutions with Tetrabutyl titanate as precursor. X-ray diffraction and tranmission electron microscopy shows that the product has uniform anatase structure with average particle size below 20 nm. The specific surface area of the TiO2 nanocrystalline powder was also investigated using BET surface area analyzer.The synthesis of tubular H3TiO3 was carried out through a soft chemical hydrothermal reaction of TiO2 powders in NaOH aqueous solutions systems. The TiO2 nanotubes can be obtained by calcining H3TiO3 at 400℃. The photocatllytic activity of nanotubular TiO2 was evaluated in a decomposition test of organic dye at 298K in an aqueous system using radiation with mercury lamp.Nitrogen-doped TiO2 nanotubes were synthesized by a wet process. The nanotubes have an anatase crystal structure with nitrogen atoms substituted into oxygen sites of TiO2. These nanotubes exhibited photocatalytic oxidation activity of organic dye into water and carbon dioxide when illuminating with visible light.
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