| Photocatalysis is a one-up field in photochemistry, and has widely applied foreground in disposing waste water. N type semiconductor is in common use in degrading environmental contamination by photocatalytic process. Of these, TiO2 has attracted considerable attention because of its chemical stability, low cost and non-toxicity. Crystal type, crystal size, specific surface area, surface hydration state, surface charge, and so on can affect the photocatalytic activity of TiO2 markedly.In this paper, surface modified TiO2 with high specific surface area was synthesized through lamellar mesoporous precursor with C18H37NH2 as template. The transformation of the mesoporous phase to an anatase phase is desirable because the latter is associated with high photocatalytic activity. The pore size for Si-substituted TiO2 and Si, RE modified TiO2 samples exhibits a bimodal distribution with one maximum in the microporous range and the other in the mesoporous range, while for rare earth doped-TiO2 and surface photosensitized TiO2 samples, it exhibits a sharp and narrow distribution in microporous range. There is a red shift in UV-Visible diffuse reflectance spectra of all surface modified TiO2 samples, indicates that surface modified TiO2 show decreasing shifts in the bandgap energy which helps to increase the photocatalytic activity of the catalysts.The photocatalytic activities were investigated with the degradation of phenol and Rhodamine B as probe reaction, respectively. The effect of crystal phase, crystal size, specific surface area and the amount of water and hydroxyl groups on the active sites of the photocatalyst surface on the photocatalytic activity of TiO2 was discussed. After surface modified, there are more hydroxyl groups forming on the photocatalyst surface. The red shift in UV-Visible diffuse reflectance spectra with the addition of rare earth, and more lamp-house used after surface photosensitized are all in favor of the photocatalytic activity of TiO2.
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