Ultrasound-assisted synthesis and visible-light-driven photocatalytic activity of Fe-incorporated TiO2 nanotube array photocatalysts

Fe incorporated TiO2 nanotube arrays (Fe-TiO2NTs) were prepared by an ultrasound-assisted impregnating-calcination method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (DRS) indicated that alpha-Fe2O3 nanoparticles were deposited into the TiO2 nanotubes, and in the mean time, some Fe3+ ions were doped into TiO2 lattice. The absorption of Fe-TiO2NTs in the visible light region increased with the increase of Fe content. The photocatalytic activity of Fe-TiO2NTs was evaluated by the degradation of methylene blue aqueous solution under visible light irradiation. The results demonstrated that the Fe-TiO2NTs exhibited significantly enhanced photocatalytic activity compared with pure TiO2NTs. Photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) analyses further confirmed that the increased photocatalytic activity of the Fe-TiO2NTs was attributed to an enhanced separation and transfer of photogenerated charge carriers. (C) 2011 Elsevier B.V. All rights reserved.