Abstract：Taking precipitated silica and TiCl₄ as raw materials, a kind of coated nano-sized TiO₂ composite photocatalysts was prepared by the means of hydrolysis-depositing method. The effect of calcination on crystal structure and photocatalytic activity of the composite photocatalysts was investigated. The results show that the decolorization rate of rhodamine B of the composite photocatalysts calcined at 700 ℃ for 2 h is 96.23% under the irradiation of 200 W Hg lamp for 35 min.

Keywords：precipitated silica; TiO₂nano-particle; photocatalysis