Hydrated titanium dioxide, h-TiO 2 , was prepared by hydrolysis of TiCl 4 with concentrated NH 3 solution.Due to its considerably high surface area h-TiO 2 can adsorb a large amount of methylene blue on its surface, about nine times as much of Degussa P25.It can photocatalyze the decomposition of methylene blue, albeit slightly inferior to Degussa P25 if adsorption is excluded.In the presence of dilute H 2 O 2 and with UV light, h-TiO 2 can bleach methylene blue as well as Degussa P25.However, under similar conditions, but without UV light, h-TiO 2 can bleach methylene blue much better than Degussa P25.