Segregation and Migration of the Oxygen Vacancies in the 3 (111) Tilt Grain Boundaries of Ceria
- Univ. of Tennessee, Knoxville, TN (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
In nanocrystalline materials, defect-grain boundary (GB) interaction plays a key role in determining the structure stability, as well as size-dependent ionic, electronic, magnetic and chemical properties. In this study, we systematically investigated using density functional theory segregation and migration of oxygen vacancies at the Σ3 [110] / (111) grain boundary of ceria. Three oxygen layers near the GB are predicted to be segregation sites for oxygen vacancies. Moreover, the presence of oxygen vacancies stabilizes this tilt GB at a low Fermi level and/or oxygen poor conditions. An atomic strain model was proposed to rationalize layer dependency of the relaxation energy for +2 charged oxygen vacancy. The structural origin of large relaxation energies at layers 1 and 2 was determined to be free-volume space that induces ion relaxation towards the GB. Our results not only pave the way for improving the oxygen transport near GBs of ceria, but also provide important insights into engineering the GB structure for better ionic, magnetic and chemical properties of nanocrystalline ceria.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1261384
- Journal Information:
- Journal of Physical Chemistry. C, Vol. 120, Issue 12; ISSN 1932-7447
- Publisher:
- American Chemical Society
- Country of Publication:
- United States
- Language:
- English
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