Titanium Dioxide:Synthesis, Doping And Photocataiytic Performance

Titanium dioxide has been extensively used in a variety of applications especially its excellent performance in environment and energy by utilize earth-abundant solar photons and the environmentally friendly, thermodynamic or chemical stability. The employment of the transition metal oxides in photocatalysis to degrade the organic pollutants into water or carbon dioxide is a very active search underway. The pure TiO2has a wide band gap of3.2eV and is easy to transform into less photosensitive rutile phase make disadvantages in practical application.1. TiO2and S-doped samples were prepared by thiourea as the sulfur source and a series of calcination temperature. The result shows that the amorphous TiO2state in the presence of acid can transform from anatase TiO2to rutile at35O℃. The S-doping made the optical absorption samples different properties from the undoped TiO2, and when the ratio of the thiourea increases, this charge becomes more obviously. The TIO2calcined at400℃shows the best catalytic effect, which would degrade about100%of the methylene blue within60min under Mercury lamp (800W).2. TiO2sphere was made by ethyl acetate as the dispersing agent, prepared by a simple hydrolysis and hydrothermal method composed by nanocrystalline with worm-hole mesoporous structure. The specific surface area of the sample could up to77.32m2/g and have anatase as its main crystalline phase leading a high catalytic activity which could decompose70%of methylene blue in70min under the300W light irradiation. The TiO2sphere was modified by Co-doping, making TiO2greatly increasing in light absorption ability. But the doping has negative effect on photocatalysis due to the defects introduced by Co doping, which would increase the electron-hole recombination rate.3. TiO2cage construction has been synthesized by the polymerization reaction between toluene and resorcinol as a gradually changing template, tetrabutyl titanate as the titanium source. TiO2adding Ti resources at different reaction stage of the temple was made to study its impact on the morphology of the sample. As the time get longer TiO2turns from particles to bulk with holes in it and if the temple react for48h, it becomes skeleton structure. We remove the carbon template through the different carbon removing time or temperature. With time get longer, the diameter raises. When the temperture becomes400℃, the highest photocatalytic efficiency has been get, presenting50%methylene blue degradation in90min.