High-density and highly cross-coated anatase TiO₂ nanotubes networks have been successfully prepared on the surface of Ti foil by alkaline hydrothermal using NaOH and Ti foil as the precursors. The nanotubes networks were analyzed using X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDX), transmission electron microscope (TEM), scanning electron microscopy (SEM), optical contact angle tester, and ultraviolet (UV) fluorescence spectrophotometer, respectively. The results showed that the nanotubes network with diameters of 30-50 nm were obtained on the Ti foil surface. The morphology of the nanotubes network possessed the three-dimensional network structure, The TiO₂ nanotubes network grew along the (101) direction of the tetragonal anatase crystal. The morphology and crystal phase of the TiO₂ nanotubes network were better at the conditions of NaOH concentration 7-10 mol/L and temperature 160-170 °C. The best contact angle of TiO₂ nanotubes network after UV-light irradition was only 5.1 ± 2.9°. Under the irradiation of mercury lamp, the nanotubes network exhibited excellent photocatalytic performance and the degradation ratio of methyl orange solution reached to 80.00 ± 2.33%. Thus, the anatase TiO₂ nanotubes network has great potential in applications for pollution photocatalytic degradation.
Keywords: alkaline hydrothermal method; hydrophilicity; nanotubes network; photocatalysis; titanium dioxide.