Facile microwave-assisted hydrothermal synthesis of TiO 2 nanotubes

Anatase TiO ₂ nanotubes grown on Ni foam substrates were successfully synthesized by treating TiO ₂ nanocrystals coated on an Ni foam in alkaline solution using a facile microwave-assisted hydrothermal method. The as-synthesized TiO ₂ nanotubes were characterized by SEM, TEM, and XRD. The effects of NaOH concentration, reaction time, hydrothermal temperature, and calcination temperature on the morphology, as well as crystal structure, of the nanotubes were investigated. TiO ₂ nanotubes synthesized under the optimal conditions were polycrystalline anatases with 4 to 5 multilayers, approximately 10 nm wide, and several tens of nanometers long. The possible formation mechanism for TiO ₂ nanotubes was also discussed in the current paper. © 2012 Elsevier B.V. All rights reserved.