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CeO 2 Nanorods and Nanocubes: Impact of Nanoparticle Shape on Dilatometry and Electrical Properties
Author(s) -
Knauth Philippe,
Harrington George F.,
Bishop Sean R.,
Saltsburg Howard,
Tuller Harry L.
Publication year - 2016
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14257
Subject(s) - nanorod , materials science , electrical resistivity and conductivity , nanoparticle , chemical engineering , enthalpy , particle size , microcrystalline , particle (ecology) , compaction , nanotechnology , composite material , thermodynamics , chemistry , crystallography , physics , oceanography , geology , electrical engineering , engineering
The electrical and dilatometric properties of CeO 2 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 CeO 2 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 P O2 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.