Investigation Of Synthesis And Applied Properties Of TiO₂ Functional Materials In Green Chemistry

In green chemistry, TiO₂ semiconductor photocatalytic agent has been received considerable attention for its application in treatment of contaminant. Many organic compounds have been degraded effectively to CO2,H₂O and small molecules. In our work, the preparation methods and properties of nano-TiO₂ photocatalytic agent, metal ions doped TiO₂ photocatalytic agent, meso- TiO₂ materials, Ag doped TiO₂ and SiO2-TiO₂antibacterial films have been investigated. In addition, using combinatorial chemistry technology, as-prepared a lots of TiO₂ photocatalytic agents were screened in high-throughput way.Firstly, nanocrystalline TiO₂ photocatalysts were prepared by sol-gel process. As-prepared TiO₂ nanocrystal was spherical, dispersed and size was in the range from 40 to 60nm. Rhodamine B solutions were chosen as simulated waste water, decomposition experiments indicated that the TiO₂ has high photocatalytic activity.Secondly, in order to widen corresponding spectrum range and enhance the photocatalytic activity of the TiO₂ under visible light, 14 metal ions doped TiO₂ photocatalytic agents were prepared. The factors of influencing on the photocatalytic activity of TiO₂ such as ion radius, electron configuration, the standard electrod potentials and the standard enthalpy of oxide were studied systemically resulted in the TiO₂ with photocatalytic activity under visible light such as Fe3+,V5+,W6+ ,Cr3+ and Ag+ doped TiO₂ photocatalytic agents were screened out.Thirdly,in order to of avert the collapsing of macroporous structure of mesoporous TiO₂ under high temperature treatment, the preparation methods have been studied mainly. In our work, SG-HT-EISA method, nanocrystal self-assembly technology and induced agent method made better than general method in preparation meso-TiO₂. Using these methods, mesoporous TiO₂, iron family doped meso-TiO₂, Si doped meso-TiO₂ have been synthesized and possess unifom macroporous structure and anatase phase. These properties are favourable to their photocatalytic activity. The decomposition experiments of Rhodamine B show that the photocatalytic activitis of meso-TiO₂; TiO₂-SBA-15 and TiO₂-MCM-41 are better than the one of TiO₂ prepared by sol-gel method.Fourthly, Ag doped TiO₂ and SiO2-TiO₂ antibacterial films were prepared firstly by a liquid phase deposition method (LPD). From structure analysis data, it was found that silver nanoparticles were trapped homogenously in TiO₂ and SiO2-TiO₂ matrix. The antibacterial effects of Ag doped TiO₂ and SiO2-TiO₂ composite films against S.Aureus and E.Coli were excellent. Antibacterial mechanism were probably the reason that Ag+ ions are released slowly from Ag doped TiO₂ and SiO2-TiO₂ composite films.Finally, using combinatorial chemstry technology, the method of high-throughput screening TiO₂ photocatalytic agents was founded. This method possesses advantages such as uncomplicated, audio-visual, high-speed, save-time, reliable, save-cost and so on. It can screen a lots of photocatalytic agents at the same time and make better than general method in screening TiO₂ photocatalytic agents. It became probably a efficacious tool in optimizing photocatalytic reactions.