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 TiO 2 crystals (anatase phase) with a diameter of ≈8 nm and a length of ≈100 nm were obtained when sol−gel-derived fine TiO 2 -based powders were treated chemically (e.g., for 20 h at 110 °C) with a 5−10 M NaOH aqueous solution. It was found by observation using a transmission electron microscope that the needle-shaped products have a tube structure. The TiO 2 nanotubes have a large specific surface area of ≈400 m 2 ·g -1 . TiO 2 nanotubes obtained in the present work are anticipated to have great potential for use in the preparation of catalysts, adsorbants, and deodorants with high activities, because their specific surface area is greatly increased. If metallic-, inorganic-, or organic-based materials can be inserted into the TiO 2 nanotubes, novel characteristics such as electric, electromagnetic, or chemical properties may be induced in the TiO 2 materials.