Abstract

TiO₂ nanotubes have recently been studied extensively due to their high surface areas and finite length scales, allowing highly efficiency electron-hole charge separation and reduced recombination. Owing to these properties they can be used for instance in photocatalysis and lithium-ion batteries. The preparation of TiO₂ nanotubes through hydrothermal process has received much attention. However, the practical application of TiO₂ nanotubes is significantly hindered by their intrinsic energy band gap > 3 eV, which ensures that these materials cannot be excited by visible light. Visible-lightactivated TiO₂ can be prepared by doping through incorporation or decoration with other metal ions, non-metal ions, and semiconductors. This review discusses various types of dopants, doping methods, and applications of doped TiO₂ nanotubes.

Keywords: Doped TiO₂, nanotubes, visible-light adsorption, hydrothermal treatment, photocatalysis.