The objective of this research was to develop a catalyst which is active in photoreaction to destruct organic compounds in waste gas and waste water. This study included using sol gel method to prepare TiO2 sol and adding various metals as the cocatalysts. Various mesoporous composite catalysts were also studied. The TiO2 sol was prepared by sol-gel method using TiCl4 as the starting material. TiCl4 was converted to Ti(OH)4 gel and H2O2 was used to hydrolyze Ti(OH)4 to form TiO2 sol The sol is stable in neutral condition and is in anatase structure. The particle size is in rhombus form and the long axis is 10 nm and short axis is 4 nm. It is well dispersed in water and does not agglomerate forever. TiO2 can be coated on the glass and become superhydrophilic. The contact angle of water on glass is 0o. It is also very active for destruction of methylene blue in water. Various metals, such as platinum, gold, silver and copper, were added on TiO2 as the cocatalysts. Au/TiO2 prepared by photodeposition had average Au particle size around 1.5 nm, which was homogeneously distributed on the surface of TiO2. The particle size of Au is a function of light source, power and irradiation time during preparation. Au/TiO2 prepared by deposition-precipitation had an Au particle size around 3 nm. Silver and copper catalysts were prepared by incipient-wetness impregnation to Degussa TiO2 and then reduced by UV light irradiation. Adding metals had significant improvement in destruction of methylene blue under UV light irradiation. It also had activity under visible light irradiation. The sunlight contains about 3% UV light. Therefore adding metal on TiO2 is very beneficial under sun light irradiation. The effect of cocatalyst was Pt> Ag> Au> Cu. The Ag/TiO2 sol prepared in this study was much more active than commercial Ag/TiO2. It is very stable in neutral condition and was very sticky on glass. It has been commercialized by some companies. In this study, we have invented the method to prepare Ag/TiO2 sol. It has commercial value. In this study, composite mesoporous materials were also synthesized. Mesoporous In-Nb oxides were synthesized using NbCl5 and In2O3 as the materials and P123 as the template. The higher the content of In, the bigger the pore size of materials and the thinner the pore wall. This materials has photoactivity. The high surface area of this material improved the photoactivity to some extent. TiO2-SBA-15 was also synthesized by sol-gel method. TiO2 was supported on the surface of SBA-15. These composite materials had high adsorption capacity to remove methylene blue due to the high surface area of SBA-15 and the activity was also quite high due to the syngertistic effect between TiO2 and SBA-15.

TiO2 sol, Au/TiO2, Ag/TiO2, Cu/TiO2, SBA-15 mesoporous material, photocatalysis, methylene blue destruction, nanocatalyst, In-Nb oxide mesoporous material, superhydrohilicity