Study On The Synthesis Of Gd/B Co-doped TiQ₂Nanoparticles And Their Erformance Of Visible Photocatalytic Activity

To degrade and eliminate harmful organic substance by using of TiO₂nanoparticles as photocatalyst is a recent-developed technology for environmentalprotection. However, the band gaps of pure TiO₂is so wide （about3.2eV） that itscatalytic activity can display only in the ultraviolet excitation （about5%of the sunlight）, resulting in the limitation of its wide applications. Therefore, the modificationof TiO₂via ion doping is an effective method to solve the above problem.In this thesis, both of Gd ion and B ion were used as the doping sources tomodify the TiO₂nanoparticles. TiO₂nanoparticles doped with Gd ion, B ion and Gd/Bions were prepared via sol-gel method, which were characterized by transmissionelectron microscope （TEM）、X-ray diffraction （XRD）、ultraviolet-visible spectrum（UV-vis）. to characterize the sample’s surface morphology，crystal transformation，crystal phase composition， and visible absorption properties. The photocatalyticactivities of the doped TiO₂were investigated through methyl orange degradationunder visible light irradiation, where the sunlight was used as light source. The resultswere given as following:（1） the doped elements and doping amount affectedsignificantly on the morphology, crystal structure and visible catalytic activity of TiO₂nanoparticles;（2） the Gd/B doping could restrict the grain growth and the phasetransformation of anatase to rutile;（3） the Gd/B doping caused the TiO₂nanoparticlesexhibit strong absorption in visible region and red-shift of the absorption spectra,implying the increase of the photo-induced carriers.（4） the highest catalytic activity,i.e the degradation percent of methyl orange is98.9%, could be reached in theconditions of doping mole fraction of0.005Gd/0.04B, annealing temperature of500℃.