Preparation of Colloidal Anatase TiO2 Secondary Snbmicroparticles by Hydrothermal Sol-Gel Method

Anatase TiO2 nanoparticles giving stable colloids of tightly aggregated secondary particles were prepared by a hydrothermal sol-gel method. The average sizes of the primary and secondary particles, as estimated by TEM and DLS, were ca. 10 nm and ca. 100 nm, respectively. These particles were dispersed milky-whitely in water without any surfactant or polymer.