PREPARATION AND CHARACTERIZATION OF QUANTUM-SIZE TITANIUM-DIOXIDE

The syntheses of transparent colloidal solutions of extremely small titanium dioxide particles (d less than 3 nm) in water, ethanol, 2-propanol, and acetonitrile are presented. Quantum-size effects are observed during particle growth and at the final stages of synthesis. They are quantitatively interpreted by using a quantum mechanical model developed by L. E. Brus. The particles prepared in aqueous solution possess the anatase structure and consist of about 200 TiO//2 molecules at their final growth stage. The colloidal particles can be isolated from solution as white powders that are soluble in water and ethanol with no apparent change in their properties. In organic solvents the quantum-size TiO//2 particles appear to form with rutile structure.