CeO2 Nanorods and Nanocubes: Impact of Nanoparticle Shape on Dilatometry and Electrical Properties

Philippe Knauth, George F. Harrington, Sean R. Bishop, Howard Saltsburg, Harry L. Tuller

Research output: Contribution to journalArticlepeer-review

4 Citations (SciVal)

Abstract

The electrical and dilatometric properties of CeO2 nanopowders were examined as function of particle shape and size, including nanorods and nanocubes. Nanorods show continuous irreversible shrinkage, linked to particle reordering and compaction. Thermal expansion of CeO2 nanocubes was analyzed and was found to be consistent with literature data for microcrystalline ceria with no apparent nanosize effects. The electrical properties of the loosely compacted nanopowders were generally found to be characterized by n-type electronic conduction, except for proton conductivity contributions associated with adsorbed moisture at temperatures below 400°C. The PO2 and temperature dependences of the conductivity were examined in terms of defect chemical models. The lower effective enthalpy of reduction for nanorods (1.5 eV) in comparison with nanocubes (1.8 eV), both being much smaller than the value found for “bulk” ceria (4.7 eV), can be related to the larger surface to volume ratio of the nanorods, where oxide ion removal is more facile and less energy costly.

Original languageEnglish
Pages (from-to)2415-2421
Number of pages7
JournalJournal of the American Ceramic Society
Volume99
Issue number7
DOIs
Publication statusPublished - 31 Jul 2016

Bibliographical note

Funding Information:
The authors acknowledge the US Department of Energy – Basic Energy Sciences, Grant DE-SC0002633, for financial support. This work made use of the MRSEC Shared Experimental Facilities at MIT, supported by the National Science Foundation under award number DMR-0819762, including the assistance of Dr. Scott Speakman with the XRD analysis. P. K. thanks H. L. T. for the kind hospitality during his sabbatical at the Massachusetts Institute of Technology and H. L.T likewise thanks P. K. for his kind hospitality during a week-long visit to Aix-Marseille University during the preparation of this manuscript. G. F. H. acknowledges financial support from the Progress-100 program at Kyushu University.

Publisher Copyright:
© 2016 The American Ceramic Society

Keywords

  • defects
  • nonstoichiometry
  • oxides
  • reduction
  • thermodynamics

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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