X-ray absorption near edge structure (XANES) measurements of ceria-based solid electrolytes

The X-ray absorption near edge structure (XANES) spectra of a series of cer ia samples doped with trivalent rare earth oxide have been measured at the L-III edges of the dopants and the cerium. These spectra give information o n the valency of the excited atom and the geometric structure of the direct neighborhood of this atom. By comparing the XANES spectra of the dopants w ith those of the pure oxides, differences in thr way the dopants are incorp orated into the ceria lattice can be observed. These differences together w ith the mismatch of the ionic radii of the dopants compared to Ce, seem to be responsible for the decreasing ionic conductivity of the lighter rare ea rth dopants. For Pr, the spectra indicate a partial oxidation to Pr-44 lead ing to a reduced conductivity. (C) 2000 Elsevier Science B.V. All rights re served.