Titanium(IV) oxide (TiO 2 ) powders synthesized by HyCOM (hydrothermal crystallization in organic media) method, which had been proved to exhibit ultra-high photocatalytic activity in several reaction systems, were used as starting material for fabrication of transparent TiO 2 thin films.HyCOM-TiO 2 powders were dispersed in aqueous solution of nitric acid to yield a TiO 2 sol stable for more than 90 days.Transparent TiO 2 thin films were successfully produced by dip-coating from the TiO 2 sol and used for photocatalytic decomposition of malachite green (MG) in an aqueous solution under aerated conditions. These films exhibited much higher rate of MG decomposition compared with those prepared from a commercially available TiO 2 sol developed for photocatalytic use (Ishihara STS-01), indicating that the excellent photocatalytic activity of original HyCOM-TiO 2 particles was preserved after immobilization on glass substrates by the present method.

Titanium(IV) oxide (TiO 2 ) nano-particles with various physical properties, which had been prepared by hydrothermal crystallization in organic media (HyCOM) and post-calcination, were used for photocatalytic decomposition of malachite green (MG)