Porous CeO2-20 wt.%TiO2 composite powders having a homogeneous distribution and nanocrystalline were successfully synthesized by a sol-gel process using titanium iso-propoxide and Ce(NO3)(3)center dot 6H(2)O as precursors. The particle sizes of the as- received porous CeO2-20 wt.%TiO2 composite powders were measured in the range from 0.3 to 10 mu m by SEM. As the calcination temperature was increased tip to 1050 degrees C, the porous composite powders having pores ranging from 0.1 nm to 3 mu m in pore size were obtained. The pore frames of CeO2-20 wt.%TiO2 composite powders were less than 500 nm thick and they were nanocrystalline with it dense structure. From a comparison of the photocatalytic activity, the porous CeO2-20 wt.%TiO2 composite powders calcined at 900 degrees C showed all excellent efficiency for the removal of phenol tinder UV light. However, in the powders calcined at 600 degrees C, there was a relatively higher photocatalytic activity than that of other powders under visible light. Hence this sample had a strong edge hand lit a blue-green wavelength range.

Keywords: Nanoparticle; microstructure; photoactivity; visible light