| Using TiCl4 to hydrolyze, joining the ammonia solution to adjust pH, adding H2O2 to dissolve Ti(OH)4, heating for the long time at low temperature to cause crystal-type conversion, nano-level anatase TiO2 hydrosol is gained. This is a kind of new method which TiO2 material can be applied in the photocatalytic field.The experiment made researches on the influencing facters which keep the stability of TiO2 hydrosol, and analyzing the hydrosol by TEM and electrophoretic tests, also expounding the stable mechanism simply.The TiO2 powder gained by the hydrosol is dried at low temperature, and analysed by FTIR> XRD and BET. The results show that there is no impurity in the preparing process, the titanium dioxide hydrosol is composed of anatase phase, and the crystallinity becomes more perfect with the increase of temperature. The BET surface areas are 220m2g-1, with temperature increasing up, the change of BET surface areas is not obvious, but pore volume and average pore diameter tend to expand.The TiO2 thin films are prepared from anatase TiO2 hydrosol by the dip coating method, and the films are annealled at low-temperature but some are not. The prepared thin films are characterized by TEM,Raman, AFM, SEM, UV-Vis. It is found that the prepared TiO2 thin films are also consisted of anatase phase's 10 nm grains, and the crystallinity is fine. The TiO2 crystal grains conglutinate and distribute uniformly on slide in the form of multi-crystal anatase phase. The as-prepared films possess a high transmittance in visible light band;its optical absorptive threshold value is about 354nm.In the aspect of the photocatalytic activity, we did some experiments and tests: TiO2 hydrosol degradated methyl orange, TiO2 powder degradated acetone, TiO2 films degradated formol and TiO2 films degradated methyl orange, confirming that the as-prepared sample possessed preferable photocatalytic activity. At the same time, the hydrophilicity of TiO2 films is fine in the sunlight.
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