Abstract: A set of nanometer TiO2 photocatalysts doped with various ions of transition metals (Cr、Mn、Fe、Co、Ni、and Cu) was prepared by using the wet impregnation method. The samples were characterized by using some bulk and surface techniques namely X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The samples were employed as catalysts for acetic acid photocatalytic oxidation degradation and carbon dioxide photocatalytic reduction in aqueous suspension, used as probe reactions. The characterization results have confirmed that the doping ions exist on the surface in the form of oxide and have no significant effect on crystal phase of the samples. Photocatalytic activities of the doped samples were improved in the order of Cr、Co、Ni、Fe、Mn、Cu. The photocatalytic activity of doped TiO2 appears to be a complex function of the dopant concentration, adsorption oxygen and the nature of doped ions.

Key words: Immersion methods, Transition metal ions, Doped, Nanocrystalline TiO₂, XPS