Fe3+-TiO2 photocatalysts prepared by combining sol–gel method with hydrothermal treatment and their characterization

Fe3+-doped anatase nanosized TiO2 photocatalysts have been prepared by combining sol–gel method with hydrothermal treatment. The samples were characterized by UV–vis diffuse reflectance spectroscopy, X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET)-specific surface area (SBET), transmission electron microscopy (TEM), atomic absorption flame emission spectroscopy (AAS), electron paramagnetic resonance (EPR) spectroscopy and X-ray photoelectron spectroscopy (XPS). From results of UV–vis diffuse reflectance spectroscopy, Fe3+-doped TiO2 extends its absorption to longer than 500 nm, which leads to an obvious photocatalatic activity under visible irradiation. From XRD, EPR, AAS and XPS, it was found that Fe exist in trivalent ionic state substituting Ti4+ in TiO2 lattice and its concentration decreases from the surface to the center of doped TiO2. The photocatalytic activity of prepared samples was investigated for the photocatalytic degradation of active yellow XRG dye. The photocatalytic activity of TiO2 doped with appropriate content of Fe3+ exceeded those of non-doped TiO2 and P25 both under UV and visible light irradiation.