Preparation of Ultra Fine TiO₂ Particles Dispersible in Organic Solvents and Their Photocatalytic Properties

Abstract

Ultra fine TiO₂ particles which dispersed in various organic solvents were synthesized through hydrolysis of a titanium alkoxide to form colloidal TiO₂ particles, followed by modification of the colloidal particles with a hydrophobic coupling agent. The organic solvent solutions of the synthesized TiO₂ particles were transparent and had high colloidal stability. Photochemical properties of the TiO₂ particles in organic solvents were studied: namely how Ti³⁺ species were formed in the particles and accumulated in them; and how the particles were photocatalytically active for oxidation of I^– and reduction of methylene blue and Ag⁺. From comparative studies of the photocatalytic reactions, the TiO₂ particles are found to have higher photocatalytic activity than commercially available anatase and rutile powders.