Ultrafine TiO₂ powders prepared from aqueous TiCl₄ solutions at room temperature

Ultrafine TiO₂ powders as rutile and anatase phase were simply precipitated at room temperature for only tens of hours by simply controlling the pH value and Ti⁴⁺ concentration via aqueous TiCl₄ solution. Under the optimal pH value and Ti⁴⁺ concentration, the average particle size of powders with rutile phase was 3.7nm, while that of powders with anatase phase was 3.0nm. The average particle size was calculated from the broadening of corresponding X-ray spectral peaks by Scherrer formula. In addition, 3.0 mol. 1^-1 are suggested to be used as concentration of stock solutions instead of the current concentration 2.0 mol. 1^-1.