Abstract: Nanocrystalline titania powders in the rutile phase were prepared by the homogeneous precipitation method
using TiCl₄ and TiCl₃ as starting materials. The products were characterized by X-ray diffraction (XRD), transmission electron
microscope (TEM) analysis and BET surface area measurement. The solution concentration and the added amount of Ti³⁺ determined the properties
of the obtained TiO₂ powders. The photocatalytic activity of the powder was also studied by using the degradation of phenol in water as a test reaction.
It shows higher photocatalytic activity both in degradation rate and in degradation efficiency, probably due to the ultrafine particle size,
higher specific surface areas and more active surface groups for physicochemical adsorption.

Key words: nanocrystalline, rutile TiO₂, TiCl₄, TiCl₃