Abstract: Nano-sized photocatalyst particles of TiO 2 and Zn-doped TiO 2 were prepared by the so- l gel method．The FTIR results of the particles show that the infrared absorption peaks split further with the increase of calcination temperature．TGA results reveal that the surface hydrophilicity of the sample in-creases with Zn doping．XRD results and the calculation results by Scherrer equation indicate that the particle size of TiO 2 increases sharply with calcination temperature．These results are similar to those ob-ained by SEM and BET．Experimental results of the photocatalytic degradation of methylene blue show that the photocatalytic activity of Zn-doped TiO 2 calcined at530℃ is highest with the Zn doping content of2％（mass fraction）．

Key words: Zn-doped TiO 2 , nano-sized TiO 2 , photocatalysis, activity