Preparation of Nano-TiO_2 by Dialysis Hydrolysis of TiCl_4

A dialysis membrane was used to make H3 and Cl- dialyze out slowly during the hydrolysis of TiCl4, and then TiO2 gel was obtained. The gel was dried by different methods and then calcined. The samples were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), BET surface area and BJH pore size distribution. For comparison, the hydrolysis of TiCl4 by the methods of heating and adding ammonia, and the hydrolysis of tetrabutyl titanate by the sol-gel method were researched. The product prepared by the dialysis method has an enormous specific surface area and the crystallites are small and uniform. It has a high phase transform temperature, keeping anatase after calcination at 700℃and transforming into rutile phase at 900℃.