Preparation and Characterization of Titania-silica Composite Particles by Pechini Sol-gel Method

Two Pechini sol-gel processes were used to prepare titania-silica composite particles. The dynamic oxidation behavior of the TiO 2 -SiO 2 powders has been characterized by thermogravimetry-differential scanning calorimetry (TG-DTG-DSC). The crystal phase and microstructure of the composite particles were investigated by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The effects of Si:Ti molar ratio and sol-gel process on the TiO 2 -SiO 2 powders were studied. The preparation of the polymeric precursors can influence the morphology of obtained TiO 2 -SiO 2 composite particles. The spherical TiO 2 -SiO 2 composite particles which are 20 nm~400 nm in diameter appear in gel-1 system. However, the TiO 2 -SiO 2 powders obtained by gel-2 system are irregular in shape and 2~15 μm in diameter which show a loose porous structure consisted of very fine granules.