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Observation of Strained PdO in an Aged Pd/Ceria-Zirconia Catalyst (2002)

Abstract

A model automotive-exhaust catalyst, Pd on Zr-rich ceria–zirconia, was characterized by X-ray diffraction, optical and electron microscopies, and micro-Raman spectroscopy following high-temperature aging. A broad bimodal distribution of Pd, introduced amongst the 10-μ m spherical particles of support material during catalyst preparation, was found to persist upon aging, and strained PdO was detected predominantly in those particles containing the higher concentration of Pd. The strain, approximately -1% by volume, was determined from the shift of the strong PdO Raman line at 650 cm -1 and the Grüneisen parameter, which was measured in a separate experiment in a diamond-anvil cell. The origin of the compressive stress that gives rise to this strain is believed to be the same as in the previously known phenomenon of Pd–metal encapsulation, but the Pd particles involved here are apparently not highly constrained within the sintered ceria–zirconia matrix prior to their oxidation.. Peer Reviewed. http://deepblue.lib.umich.edu/bitstream/2027.42/44260/1/10562_2004_Article_369224.pdf

Publication details

Download	, http://hdl.handle.net/2027.42/44260
Publisher	Kluwer Academic Publishers-Plenum Publishers; Plenum Publishing Corporation ; Springer Science+Business Media
Contributors	Department of Materials Science and Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, MI, 48109-2136, USA, Department of Materials Science and Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, MI, 48109-2136, USA, Ford Research Laboratory, MD3179/SRL, P.O. Box 2053, Dearborn, MI, 48121, USA, Ford Research Laboratory, MD3179/SRL, P.O. Box 2053, Dearborn, MI, 48121, USA, Ford Research Laboratory, MD3179/SRL, P.O. Box 2053, Dearborn, MI, 48121, USA, Ford Research Laboratory, MD3179/SRL, P.O. Box 2053, Dearborn, MI, 48121, USA, Ann Arbor
Repository	University of Michigan (United States)
Keywords	strain, XRD, Pharmacy, Chemistry, Physical Chemistry, Industrial Chemistry/Chemical Engineering, aging, automotive-exhaust catalyst, ceria–zirconia, encapsulation, Grüneisen parameter, Pd, PdO, Raman spectroscopy, SEM, TEM, Biological Chemistry, Materials Science and Engineering, Chemistry, Chemical Engineering, Engineering, Science, Health Sciences
Language	English