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Title: Equilibrium oxygen storage capacity of ultrathin CeO 2-δ depends non-monotonically on large biaxial strain

Elastic strain is being increasingly employed to enhance the catalytic properties of mixed ion–electron conducting oxides. However, its effect on oxygen storage capacity is not well established. Here, we fabricate ultrathin, coherently strained films of CeO 2-δ between 5.6% biaxial compression and 2.1% tension. In situ ambient pressure X-ray photoelectron spectroscopy reveals up to a fourfold enhancement in equilibrium oxygen storage capacity under both compression and tension. This non-monotonic variation with strain departs from the conventional wisdom based on a chemical expansion dominated behaviour. Through depth profiling, film thickness variations and a coupled photoemission–thermodynamic analysis of space-charge effects, we show that the enhanced reducibility is not dominated by interfacial effects. On the basis of ab initio calculations of oxygen vacancy formation incorporating defect interactions and vibrational contributions, we suggest that the non-monotonicity arises from the tetragonal distortion under large biaxial strain. Finally, these results may guide the rational engineering of multilayer and core–shell oxide nanomaterials.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [3] ;  [1] ;  [1] ;  [1] ;  [4] ;  [5] ;  [6]
  1. Stanford Univ., Stanford, CA (United States)
  2. SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Trinity College Dublin, Dublin (Ireland)
  3. Lund Univ., Lund (Sweden)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  5. SLAC National Accelerator Lab., Menlo Park, CA (United States); Univ. of Pennsylvania, Philadelphia, PA (United States)
  6. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Grant/Contract Number:
AC02-76SF00515; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 8; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE
OSTI Identifier:
1368692
Alternate Identifier(s):
OSTI ID: 1379851