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Title: Origins and implications of the ordering of oxygen vacancies and localized electrons on partially reduced CeO2(111)

In this study, we use density functional theory to explain the preferred structure of partially reduced CeO2(111). Low-energy ordered structures are formed when the vacancies are isolated (maximized intervacancy separation) and the size of the Ce3+ ions is minimized. Both conditions help minimize disruptions to the lattice around the vacancy. The stability of the ordered structures suggests that isolated vacancies are adequate for modeling more complex (e.g., catalytic) systems. Oxygen diffusion barriers are predicted to be low enough that O diffusion between vacancies is thermodynamically controlled at room temperature. The O-diffusion-reaction energies and barriers are decreased when one Ce f electron hops from a nearest-neighbor Ce cation to a next-nearest-neighbor Ce cation, with a barrier that has been estimated to be slightly less than the barrier to O diffusion in the absence of polaron hopping. In conculsion, this indicates that polaron hopping plays a key role in facilitating the overall O diffusion process, and depending on the relative magnitudes of the polaron hopping and O diffusion barriers, polaron hopping may be the kinetically limiting process.
 [1] ;  [2] ;
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computer Science and Mathematics Division
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 92; Journal Issue: 14; Journal ID: ISSN 2469-9950
American Physical Society (APS)
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Org:
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY CeO2; O vacancies; density functional theory