| Nano-TiO2 has attracted much attention in the resent years as a new type of inorganic function material, because of its excelled property. However, agglomerating in organic solvent and photocatalysis limit its application. Accordingly, the key that nano-TiO2 can be applied widely lies in that nano-TiO2 is coated with inorganic and organic compound for the purpose of shielding its photocatalysis and dispersing it well in the organic solvent.This paper reports that nano-TiO2 is coated with Al2O3, SiO2 or both together by chemical liquid deposition. The coating is characterized by Raman spectroscopy, X-ray diffraction spectroscopy(XRD), Fourier-transform infrared spectroscopy(FT-ER) and Transmission electron microscope (TEM). The content of coating compound and anti-ultraviolet capacity of nano-TiO2 are measured by X-ray fluorescence(XRF) and UV-Vis spectrophometer. Nano-TiO2 coated with inorganic compound is modified with silane couple reagent, and the content of coating compound can be calculated from the difference of samples weightlessness after they are calcined at 850C. The wetting capacity and the dispersing of diverse specimens are investigated.The inorganic coating on the surface of nano-Titania is noncrystal. SiO2 is coated on the surface of nano-TiO2 to form silica gel polymer with a Ti-O-Si bind, and Al compound exists with A1OOH and part A1(OH)3. According to different reaction condition, three coating inorganic morphologies can be acquired: part coating, nucleus coating and integrate film coating, and the integrate and dense film can shield effectively photocatalysis of nano-TiO2. The acquirement of morphologies is determined of super-saturation of coating compound, and it can be drew a conclusion from the thermodynamics theory that the super-saturation for forming nucleus in the same substance is higher than one in the different substance, that is c* < c; Besides, developing of film have no energy barrier. The dense and integrate film of Si compound, corresponding to 5% SiO2, can be achieved in the following technology condition, that is, mixing the slurry round fully at pH=10, adding the coating reagent and neutralization reagent into the slurry at the same time in the 60 minutes at 85C~95C at pH=9~10, finally aging it for 120 minutes. Also, a film of aluminum compound coated TiO2 particles if the reaction condition is the same, but the aluminum compound exists as dissociative particles between nanoTiO2 particles if the slurry is acidic, and that partcoating can be acquired if the slurry isn't mixed fully when the coating reagent and neutralization reagent are being adding into. The inorganic film can increase wetting capacity for xylene , but the film improves stability of nano-TiO2 in water much more effectively than the dissociative particle when it is dispersed fully.When particles are modified with silane coupling agent, the -OH group on the surface of nano-TiO2 provides reaction ground, so its exiting is the key that agent can be grafted successfully to the surface of nano-TiO particles. The most of agent amount grafted to the surface of particle is up to 1%, but the wetting capacity for xylene is the best when the amount is 1.2%. And if the amount is over 3%, the wetting capacity doesn't change with coating amount of silane coupling agent. Therefore, coating amount of silane coupling agent is best less than 3%, and 1.2% is optimal amount.The surface modification of nano-TiO2 can't impair its anti-ultraviolet capacity, by contraries, they can absorb more short band ultraviolet radiation.
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