Effect of Co, Ga, and Nd additions on the photocatalytic properties of TiO2 nanopowders

In the present study, metal-ion-doped TiO2 powders were prepared by a sol-gel process using titanium isopropoxide as a Ti precursor and cobalt, gallium, or neodymium as a dopant. For the prepared doped TiO2 nanopowders, the photocatalytic behaviors in the decomposition of aqueous 1,4-dichlorobenzene (DCB) were investigated as a function of doping level and preparation conditions. We found that all of the metal ion doping improved the photocatalytic activity of TiO2, though Nd doping was the most effective and Co doping was least effective. XRD analyses showed that doping with Ga and Nd ions suppresses the anatase-to-rutile phase transition for TiO2, whereas doping with Co did not influence the phase transition. The UV-visible absorption spectra for these metal-ion-doped samples were red-shifted by similar to 20-40 nm depending upon the doping level.