Local structure of the metal-oxygen bond in compositionally homogeneous, nanocrystalline zirconia-ceria solid solutions synthesized by a gel-combustion process

摘要

Compositionally homogeneous ZrO2-CeO2 nanopowders have been characterized by Raman and extended x-ray absorption fine structure (EXAFS) spectroscopies. These techniques revealed a tetragonal-to-cubic phase transition as a function of CeO2 content, as observed in a previous synchrotron x-ray diffraction study. The tetragonal-cubic phase boundary was found to be at (85 +/- 5) mol% CeO2. The EXAFS study demonstrated that this transition is related to a tetragonal-to-cubic symmetry change of the Zr-O first neighbour coordination sphere, while the Ce-O coordination sphere preserves its cubic symmetry over the whole composition range.