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.