Preparation and characterization of CeO2/TiO2 nanoparticles by flame spray pyrolysis

Nanocrystalline TiO2, CeO2 and CeO2-doped TiO2 have been successfully prepared by one-step flame spray pyrolysis (FSP). Resulting powders were characterized with X-ray diffraction (XRD), N2-physisorption, Transmission Electron Microscopy (TEM) and UV–Vis spectrophotometry. The TiO2 and CeO2-doped TiO2 nanopowders were composed of single-crystalline spherical particles with as-prepared primary particle size of 10–13 nm for Ce doping concentrations of 5–50 at%, while square-shape particles with average size around 9 nm were only observed from flame-made CeO2. The adsorption edge of resulting powder was shifted from 388 to 467 nm as the Ce content increased from 0 to 30 at% and there was an optimal Ce content in association with the maximum absorbance. This effect is due to the insertion of Ce3+/4+ in the TiO2 matrix, which generated an n-type impurity band.