TiO2 nanocrystals were prepared by a photo-assisted sol-gel process in whic
h tetrabutoxide titanate was hydrolyzed in acidic medium under ultraviolet
irradiation. X-ray diffraction and Raman spectra showed that the as-prepare
d TiO2 particles without further annealing were well-crystallized anatase.
Such TiO2 particles were easily immobilized on dacron cloth and showed very
high photocatalytic activity. In contrast, TiO2 particles were ill crystal
lized and showed lower activity when no light was introduced under otherwis
e equal conditions.