Preparation and size control of cube-shaped hydrous titanium (N) oxide fine particles by a colloid aging method

The effects of the concentration of titanium(IV) chloride solution, aging temperature and time, and the pH of solution on the morphology and size of hydrous titanium(IV) oxide fine particles formed by a colloid aging method were studied in detail. Cube-shaped particles of 0.20 mu m in size mere formed by aging 2.5 x 10(-2) mol . dm(-3) titanium(IV) chloride solution at room temperature for 5 d. The cube-shaped particles were easily attained by decreasing the titanium(IV) chloride concentration and/or increasing the aging temperature. The aging of 5.0 x 10(-2) mol . dm(-3) titanium(IV) chloride solution with urea at 90 degrees C for 20h gave needlelike-shaped, cube-shaped, and spherical particles in the ranges of pH<1, 1 less than or equal to pH<2 and 6<pH, respectively. Cube-shaped particles of 0.24 mu m in size used as seeds were successively grown to 0.38 pm in size under the same aging conditions described above except without urea. It is concluded that both the chloride ion and the pH of solution play an important role on the formation of cube-shaped hydrous titanium(IV) oxide fine particles.