Research On Synthesis, Characterization And Rare Earth Ion-doped Modification Of Mesoporous TiO₂

C16PyBr and PEG-1000 pocess many virtues such as low price, innocuity, low dosage, and is easily to be removed. In this dissertation, the mesoporous TiO₂ with the high specific surface area, average pore and high thermal stability has been prepared in the presence of mixed-templates with sol-gel method for the first time. The influences of different templates, molar ratio of template to titanium source, calcined temperature and other preparation conditions such as pH values of system, quantity of solvent, long-time laying aside temperature and time, etc. on mesoporous TiO₂ were investigated. Finally, we obtained the optimum synthetic conditions of mesoporous TiO₂. In addition, Sm3+, Dy3+ and Pr3+ were doped into the mesoporous TiO₂ in order to increase the catalysts activity and realize visible-light responsive of mesoporous TiO₂. The mesoporous TiO₂ and doped mesoporous TiO₂ were characterized by the means of XRD, TEM, TG-DTA, N2 adsorption and desorption, UV-vis and degradation experiments.The results show: compared with the materials which prepared with other three single templates(CTAB,C16PyBr and PEG-1000), mesoporous TiO₂ prepared with 7.5:1 of the C16PyBr to PEG-1000 to titanium source is the best. With the pH value of 5, calcination at 500℃for 2 hours under the oxygen atmosphere, the mesoporous TiO₂ with regular spherical shape, high thermal stability (550℃)and large surface area of 314.7m2/g were obtained. According to the results of degradation experiments, we find the high degradation rate of 72.59% to the methyl orange solution under UV for 2 hours.There were obvious effects of doping RE into mesoporous TiO₂ on the catalysts activity of mesoporous TiO₂.The introduction of Sm3+ makes absorption intensity decrease. Significantly , the absorption intensity increased and absorption edge had a little red-shift when Dy3+ was doped. The introduction of Pr3+ make absorption strength improved greatly, the absorption edge moved from 390 nm to 420nm. Study found not only doped type had a great influence to photocatalytic activity but also doping amount, namely, the photocatalytic activity was increased first, then was declined with doping amount increasing. The best concentrations of Dy3+ and Pr3+is 0.6%.