Facile microwave-assisted hydrothermal synthesis of TiO2 nanotubes

► Microwave-assisted hydrothermal method for anatase TiO2 nanotubes. ► Anatase TiO2 nanotubes were successfully grown on Ni foam. ► Polycrystalline anatase phase of TiO2 nanotube has 4 to 5 shell layers. ► Anatase-to-rutile phase transition of TiO2 nanotube was observed at 650 °C.