Facile microwave-assisted hydrothermal synthesis of TiO2 nanotubes

Anatase TiO2 nanotubes grown on Ni foam substrates were successfully synthesized by treating TiO2 nanocrystals coated on an Ni foam in alkaline solution using a facile microwave-assisted hydrothermal method. The as-synthesized TiO2 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. TiO2 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 TiO2 nanotubes was also discussed in the current paper. (C) 2012 Elsevier B.V. All rights reserved.