Structural effects of niobium and silver doping on titanium dioxide nanoparticles

Pure, Nb-doped and Ag-doped titania nanoparticles were synthesized by sol-gel technique with dopant concentrations ranging from 0.5 to 1.5 atomic percent Nb or Ag. The annealing temperatures ranged from 250 to 900 degrees C. Changes in phase transformation of the doped samples with reference to pure titania were studied. It was found that Nb doping stablizes the anatase phase while Ag doping accelerates the transformation from anatase to rutile at a concentration higher than 0.5 at. %. The samples were analyzed by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and Energy Dispersive X-ray Spectroscopy (EDS).