Nanoscale oxygen defect gradients in UO
actinide oxides
electron energy loss spectroscopy
scanning transmission electron microscopy
surface oxidation
uraninite
Journal
Proceedings of the National Academy of Sciences of the United States of America
ISSN: 1091-6490
Titre abrégé: Proc Natl Acad Sci U S A
Pays: United States
ID NLM: 7505876
Informations de publication
Date de publication:
27 Aug 2019
27 Aug 2019
Historique:
pubmed:
11
8
2019
medline:
11
8
2019
entrez:
11
8
2019
Statut:
ppublish
Résumé
Oxygen defects govern the behavior of a range of materials spanning catalysis, quantum computing, and nuclear energy. Understanding and controlling these defects is particularly important for the safe use, storage, and disposal of actinide oxides in the nuclear fuel cycle, since their oxidation state influences fuel lifetimes, stability, and the contamination of groundwater. However, poorly understood nanoscale fluctuations in these systems can lead to significant deviations from bulk oxidation behavior. Here we describe the use of aberration-corrected scanning transmission electron microscopy and electron energy loss spectroscopy to resolve changes in the local oxygen defect environment in [Formula: see text] surfaces. We observe large image contrast and spectral changes that reflect the presence of sizable gradients in interstitial oxygen content at the nanoscale, which we quantify through first-principles calculations and image simulations. These findings reveal an unprecedented level of excess oxygen incorporated in a complex near-surface spatial distribution, offering additional insight into defect formation pathways and kinetics during [Formula: see text] surface oxidation.
Identifiants
pubmed: 31399548
pii: 1905056116
doi: 10.1073/pnas.1905056116
pmc: PMC6717280
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
17181-17186Informations de copyright
Copyright © 2019 the Author(s). Published by PNAS.
Déclaration de conflit d'intérêts
The authors declare no conflict of interest.
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