Flame synthesis of titania particles from titanium tetraisopropoxide in premixed flames

An experimental investigation of flame synthesis of titania particles was conducted in premixed flames. The titanium precursor and silicon dopant used in this study were titanium tetraisopropoxide (TTIP) and hexamethyldisiloxane (HMDS), respectively. The objective of this study was to investigate the influence of flame condition, TTIP concentration, and HMDS on the phase composition and particle morphology of titania synthesized in flames. It was found that the anatase content of titania particles made in flames was appreciably increased by the increase of oxygen concentration in the oxidizer. The increase of flame temperature results in the decrease of anatase content. A significant increase in rutile content of titania particles was observed by increasing the particle residence time at high temperatures. The doping of HMDS in flames inhibits the transformation of anatase to rutile phase and, therefore, reduces the rutile content of product particles. Under the flame doped with low concentrations of HMDS, titania particles with SiO2 particle agglomerates attached were produced. Further increase of the HMDS concentration up to the Si to Ti molar ratio equal to 0.375 results in the formation of a large amount of SiO2 agglomerates in the product.