Preparation and analysis of zirconia doped ceria nanocrystal dispersions

Crystalline and highly dispersible solid solutions with the general formula Ce1-xZrxO2-delta, where delta represents any possible oxygen vacancies, and in the ceria rich region were prepared using an inorganic sol-gel technique. The particle size distributions of the transparent sols were measured using photon correlation spectroscopy and found to be less than 25 nm with narrow distributions. Compositional analysis using EDAX confirmed the correct zirconia doping. Lattice parameters, structural and crystallite size data for the dried sols and heated powders using X-ray diffraction confirmed a cubic structure stable to at least 1000degreesC with crystallite sizes varying from 34 (A) over circle to 55 nm, depending on calcination temperature and composition. Dispersions of the nanocrystals on silica were studied using high resolution TEM/EDAX, the structure and compositions of individual nanocrystals closely matching those of the bulk agglomerated powders, showing exceptional homogeneity. (C) 2002 Elsevier Science Ltd. All rights reserved.