Oxidation-state sensitive imaging of cerium dioxide by atomic-resolution low-angle annular dark field scanning transmission electron microscopy.

Autor: Johnston-Peck AC; Materials Measurement Lab, National Institute of Standards Technology, Gaithersburg, MD 20899, USA. Electronic address: aaron.johnston-peck@nist.gov., Winterstein JP; Center for Nanoscale Science and Technology, National Institute of Standards Technology, Gaithersburg, MD 20899, USA., Roberts AD; Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, FL 32611, USA., DuChene JS; Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, FL 32611, USA., Qian K; Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, FL 32611, USA., Sweeny BC; Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, FL 32611, USA., Wei WD; Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, FL 32611, USA., Sharma R; Center for Nanoscale Science and Technology, National Institute of Standards Technology, Gaithersburg, MD 20899, USA., Stach EA; Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11793, USA., Herzing AA; Materials Measurement Lab, National Institute of Standards Technology, Gaithersburg, MD 20899, USA.
Jazyk: angličtina
Zdroj: Ultramicroscopy [Ultramicroscopy] 2016 Mar; Vol. 162, pp. 52-60. Date of Electronic Publication: 2015 Dec 17.
DOI: 10.1016/j.ultramic.2015.12.004
Abstrakt: Low-angle annular dark field (LAADF) scanning transmission electron microscopy (STEM) imaging is presented as a method that is sensitive to the oxidation state of cerium ions in CeO2 nanoparticles. This relationship was validated through electron energy loss spectroscopy (EELS), in situ measurements, as well as multislice image simulations. Static displacements caused by the increased ionic radius of Ce(3+) influence the electron channeling process and increase electron scattering to low angles while reducing scatter to high angles. This process manifests itself by reducing the high-angle annular dark field (HAADF) signal intensity while increasing the LAADF signal intensity in close proximity to Ce(3+) ions. This technique can supplement STEM-EELS and in so doing, relax the experimental challenges associated with acquiring oxidation state information at high spatial resolutions.
(Published by Elsevier B.V.)
Databáze: MEDLINE
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