Spin-polarized density functional theory with the inclusion of on-site Coulomb correction (DFT+U) calculation was carried out to study the oxygen vacancy and migration of Ce1−xZrxO2 in a series of Ce/Zr ratios. Substitution of Zr4+ ion in CeO2 creates activated oxygen in Ce1−xZrxO2, leading to higher oxygen storage capacity (OCS) compared to CeO2 due to its structural and electronic modifications. It was found that the oxygen vacancy formation energy (Ef) was lowered even by small amounts of zirconia; the oxide with a content of 50% zirconia exhibited the lowest Ef and the best OCS. This indicated that the O vacancy was most easily created near the Zr centers. In addition, the activation energy calculations for oxygen vacancy migration around Zr dopant showed facile oxygen migration through the Ce1−xZrxO2 materials, especially for 50% Zr-doped ceria. The detailed electronic analysis was also carried out to gain insights into the higher OCS of the Ce1−xZrxO2 catalyst.

Oxygen Vacancy Formation and Migration in Ce1−xZrxO2 Catalyst: a DFT+U Calculation. H.T.Chen, J.G.Chang: Journal of Chemical Physics, 2010, 132[21], 214702