The local structure of the M-O bond in CeO2-ZrO2 mixed oxides is investigated with the aim of finding a correlation between structural parameters and oxygen exchange properties. It is found that insertion of ZrO2 into the CeO2 lattice strongly perturbs the symmetry of the M-O bond. As the content of CeO2 in CeO2-ZrO2 solid solution is increased from 20 to 80 mol%, tetragonal, (t, t′, t″) and cubic phases are formed. The local symmetry of the Zr-O bond is strongly perturbed by the increase in CeO2 content while no significant modification of the first Ce-O coordination sphere is found, except for lengthening of the Ce-O bond consistent with lattice parameter increase. The perturbation of the Zr-O coordination sphere, which leads to highly disordered oxygen in the lattice, is indicated as responsible for the high oxygen mobility in CeO2-ZrO2 mixed oxides.
Titolo: | Redox properties-local structure relationships in the Rh-loaded CeO2-ZrO2 mixed oxides |
Autori: | |
Data di pubblicazione: | 1999 |
Rivista: | |
Abstract: | The local structure of the M-O bond in CeO2-ZrO2 mixed oxides is investigated with the aim of finding a correlation between structural parameters and oxygen exchange properties. It is found that insertion of ZrO2 into the CeO2 lattice strongly perturbs the symmetry of the M-O bond. As the content of CeO2 in CeO2-ZrO2 solid solution is increased from 20 to 80 mol%, tetragonal, (t, t′, t″) and cubic phases are formed. The local symmetry of the Zr-O bond is strongly perturbed by the increase in CeO2 content while no significant modification of the first Ce-O coordination sphere is found, except for lengthening of the Ce-O bond consistent with lattice parameter increase. The perturbation of the Zr-O coordination sphere, which leads to highly disordered oxygen in the lattice, is indicated as responsible for the high oxygen mobility in CeO2-ZrO2 mixed oxides. |
Handle: | http://hdl.handle.net/11368/1694230 |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1006/jcat.1998.2335 |
Appare nelle tipologie: | 1.1 Articolo in Rivista |