Fabrication and characterization of highly-ordered titania nanotubes via electrochemical anodization

Highly ordered titania nanotube arrays are fabricated via anodization process in electrolytes containing HF and acetic acid. Graphite was used as cathode. The size of titania can be controlled by changing anodizing voltage and bath temperature. From FE-SEM images, we observed the microstructure of titania nanotubes. Whereas, these nanotubes were amorphous; to induce crystallinity, the products were annealed at different temperatures. XRD analysis shows that the anatase and rutile phase emerge at different conditions. The optical properties were characterized via UV–vis absorption analysis. On the basis of these work, a discussion on the growth mechanism of nanotube structure was presented in this paper.