Dopants in Flame Synthesis of Titania

Abstract

The effect of dopants on the characteristics of titania particles made by oxidation of TiCl 4 in a laminar diffusion flame reactor is presented. Introduction of dopant SiCl 4 inhibits the transformation of anatase to rutile, due to the formation of interstitian solid solution of SiO 2 and TiO 2 . Silica decreases the sintering rate of titania and decreases the primary particle size, and, as a result, the specific surface area increases. Intruduction of SnCl 4 enhances the transformation of anatase to rutile, due to the similar crystalline structure of SnO 2 and rutile titania. However, the presence of SnO 2 and rutile titania. However, the presence of SnO 2 does not affect the primary particle size or the specific surface area of titania particles. Introduction of AICI 3 enhances the transformation of anatase to rutile, due to the formation of excess oxygen vacancies as Al 2 O 3 and TiO 2 form a substitutional solid solution.