Titania has been used extensively in pigment, cosmetics, photocatalyst and coating. It has been reported that the spherical powders with a narrow size distribution is the most desired state. In this study, titania powders were synthesized by thermal hydrolysis of TiCl4 in a mixed solvent of n-propanol and water. The effects of preparation parameters such as synthesis temperature, the concentration of reacting species, the alcohol/water ratio, and the concentration of steric dispersant, were investigated. Hydroxypropyl cellulose (HPC) was used as a steric dispersant in this study. The morphology of the precipitates was controlled by the dielectric constant of the solvent. This can be regulated by changing the volume ratio of n-proponal to water (RH ratio) of the mixed solvent. The titania sample synthesized at an RH ratio of 3 was spherical and uniform-dispersed. Adding HPC made particles more uniformed-dispersed. The titania particles in different solid contents were all spherical, but the particle size increased with an increase of the solid content. The titania particles became not uniform at high synthesized temperature. The effect of the temperature gradient in the solvent plays an important role on the morphology of TiO2.
- Thermal hydrolysis