FORMATION OF TITANIUM-OXIDE NANOTUBE

Nanotubes composed of various materials such as carbon, boron nitride, and oxides have been studied recently. In this report, the discovery of a new route for the synthesis of a nanotube made of titanium oxide is presented. Needle-shaped TiO2 crystals (anatase phase) with a diame ter of approximate to 8 nm and a length of approximate to 100 nm were obtained when sol-gel-derived fine TiO2-based powders were treated che mically (e.g., for 20 h at 110 degrees C) with a 5-10 M NaOH aqueous s olution. It was found by observation using a transmission electron mic roscope that the needle-shaped products have a tube structure. The TiO 2 nanotubes have a large specific surface area of approximate to 400 m (2).g(-1). TiO2 nanotubes obtained in the present work are anticipated to have great potential for use in the preparation of catalysts, adso rbants, and deodorants with high activities, because their specific su rface area is greatly increased. If metallic-, inorganic-, or organic- based materials can be inserted into the TiO2 nanotubes, novel charact eristics such as electric, electromagnetic, or chemical properties may be induced in the TiO2 materials.