Peroxo method for preparation of composite silica-titania spheres

Composite silica-titania spherical particles, from the nanometer to submicron size, have been synthesized via a new template-free method, being achieved by the reaction of aqueous titanium peroxo complex with TEOS (tetraethylorthosilicate) in aliphatic alcohols. The choice of the solvent greatly affects the growth of silica-titania particles. It has been established that size of the spheres increases as carbon chain length of alcohol extends (from methanol to n-propanol). The nanometer size SiO2-TiO2 spheres with mean diameter of about 50 nm are formed in the methanol solution, while n-propanol promotes particle growth up to 400 nm. The synthesized composites retain amorphous structure up to 500 °C due to the formation of Si-O-Ti heterolinkages, whose presence has been confirmed by FTIR and XPS studies.