Synthesis, Characterization of Ce-doped TiO2 Nanotubes with High Visible Light Photocatalytic Activity

Metallic doping effectively extends the light response range of TiO2 photocatalysts from the ultraviolet (UV) to the visible region. We prepared Ce-doped TiO2 nanotubes (Ce-TiO2 NTs) using a sol-gel process followed by a hydrothermal treatment. The Ce-TiO2 NTs were characterized by X-ray diffraction, transmission electron microscopy, Brunauer-Emmett-Teller surface area, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), and photoluminescence (PL) spectroscopy. Given that the optical absorption was extended to wavelengths of 600 nm, the Ce-TiO2 NTs demonstrated excellent photocatalytic activity for degrading methylene blue under visible light irradiation. Ce-TiO2 NTs with various amounts of Ce doping (0.06-0.40 g of cerium nitrate hexahydrate added during preparation) were tested, and the 0.12Ce-TiO2 NTs showed the highest photocatalytic activity, 7 times higher than that of P25. For their efficient photodegrading of dyes under visible light, these Ce-TiO2 NTs may be useful for waste water treatment.