Synthesis and characterization of anatase TiO₂ nanotubes with uniform diameter from titanium powder

Anatase TiO₂ nanotubes and titanate nanotubes have been successfully synthesized via hydrothermal synthesis followed by post-treatment from titanium powder. The morphology and crystalline structure of the nanotubes are characterized in detail with transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) respectively. The nanotubes have an average outer diameter of around 9-10 nm and the inner diameter around 3-4 nm with several hundred nanometers in length. A mechanism for the anatase TiO₂ nanotubes transformation has also been proposed. Nanotubes are formed during the solvent thermal process, and the compositions are changed by subsequent ionic exchange and dehydration under high temperature. These tubular materials can be very useful in the fields of photocatalysts, photoelectronics and energy-storage technologies.