TY - JOUR
T1 - CeO2 Nanorods and Nanocubes
T2 - Impact of Nanoparticle Shape on Dilatometry and Electrical Properties
AU - Knauth, Philippe
AU - Harrington, George F.
AU - Bishop, Sean R.
AU - Saltsburg, Howard
AU - Tuller, Harry L.
N1 - 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
PY - 2016/7/1
Y1 - 2016/7/1
N2 - 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.
AB - 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.
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U2 - 10.1111/jace.14257
DO - 10.1111/jace.14257
M3 - Article
AN - SCOPUS:84963576488
SN - 0002-7820
VL - 99
SP - 2415
EP - 2421
JO - Journal of the American Ceramic Society
JF - Journal of the American Ceramic Society
IS - 7
ER -