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

详细信息    查看全文

• 作者：Philippe Knauth ; George F. Harrington ; Sean R. Bishop ; Howard Saltsburg and Harry L. Tuller
• 刊名：Journal of the American Ceramic Society
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：99
• 期：7
• 页码：2415-2421
• 全文大小：782K
• ISSN：1551-2916

文摘

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 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.