Iron and chromium doped titanium dioxide nanotubes for the degradation of environmental and industrial pollutants

Pure titanate nanotubes and titanate nanotubes doped with iron (III) and chromium (III) were fabricated by the hydrothermal treatment in methanol and sodium hydroxide mixture. The fabricated nano tubes have high surface area, high aspect ratio, consisted of very good surface morphology and high metals dispersion. The morphology, crysralline phase, composition were characterized by powdered X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Barrett-Joyner-Halenda methods and X-ray photoelectron spectroscopy. The results showed that nanotubes possess anatase phase and are composed up of 8–12 nm in diameter and 360–400 nm in length. The band gap of the titanium dioxide nanotubes was determined using transformed diffuse reflectance spectroscopy according to the Kubelka-Munk theory, showed pronounced band gap decrease on doped titanium dioxide nanotubes. The photocatalytic activity of doped nanotubes were evaluated in terms of degradation of phenol and photoreduction of carbon dioxide into methanol and ethanol under Ultra violet and Infra red irradiation. It was found that with iron (III) and chromium (III) doped titanium dioxide nanotubes exhibited much higher photocatalytic activity than undoped titanate nanotubes.