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Role of stress in oxide wetting of metal particles in ceria-zirconia-supported Pd catalysts


EMSL Project ID
33997

Abstract

Metal-support interactions play a significant role in many heterogeneous catalysts, sometimes affecting catalytic performance dramatically. Cross-sectional transmission electron microscopy (TEM) has proven to be a unique tool for investigating such interactions, for example, by providing a visual image of oxide-supported metal particles which may be used to calculate thermodynamic properties of the metal-oxide interface. In the proposed work, we will apply cross-sectional TEM to the study of a metal-support interaction that is believed to affect the stability and durability of automotive exhaust-gas three-way catalysts. Specifically, we will analyze the effect of compressive stress in ceria-zirconia, induced by reduction, on the oxide wetting of supported Pd particles, observed previously in model planar catalysts. Our goal is to determine the role of stress, relative to chemical bonding between ceria-zirconia and Pd, in driving the oxide-wetting process. Such fundamental knowledge is needed for a more complete scientific understanding of aging phenomena in this important class of environmental catalysts.

Project Details

Project type
Exploratory Research
Start Date
2009-04-06
End Date
2010-04-11
Status
Closed

Team

Principal Investigator

Xiaoqing Pan
Institution
University of Michigan

Team Members

Obiefune Ezekoye
Institution
University of Michigan

George Graham
Institution
University of Michigan

Related Publications

Chapter 5 from Ph.D. thesis of Obiefune K. Ezekoye, Department of Materials Science and Engineering, University of Michigan (2010).
Ezekoye OK, MI Nandasiri, T Varga, P Nachimuthu, W Jiang, SVNT Kuchibhatla, S Thevuthasan, XQ Pan, and GW Graham. 2011. "Investigation of precious-metal/metal-oxide-support interactions in automotive catalytic converters using a Pd/ Ce0.7Zr0.3O2 model planar catalyst system." Abstract submitted to AVS 58th International Symposium and Exhibition, Nashville, TN. PNNL-SA-79801.
Zhang S, MB Katz, K Sun, OK Ezekoye, MI Nandasiri, HW Jen, GW Graham, and XQ Pan. 2013. "Spatial Distribution Of Cerium Valence In Model Planar Pd/Ce0.7Zr0.3O2 Catalysts." Journal of Catalysis 300:201-204. doi:10.1016/j.jcat.2013.01.013