AVS 52nd International Symposium
    Surface Science Thursday Sessions
       Session SS3-ThM

Paper SS3-ThM7
The Chemical Properties of Pd-Au Alloy Surfaces

Thursday, November 3, 2005, 10:20 am, Room 203

Session: Reactivity of Bimetallic Surfaces
Presenter: T. Wei, Texas A&M University
Authors: T. Wei, Texas A&M University
J.H. Wang, Texas A&M University
C.-W. Yi, Texas A&M University
D.W. Goodman, Texas A&M University
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The chemisorptive behavior of CO on Pd-Au alloy films and silica-supported Pd-Au nano-clusters has been studied by infrared reflection adsorption spectroscopy (IRAS). The relative influence of geometric versus electronic effects has been addressed by comparing the alloy and single component surfaces. A unique CO vibrational feature at 2088 cm-1 , corresponding to CO adsorbed on isolated Pd sites on Au, is clear evidence of an ensemble effect. On the other hand, the IRAS data for CO adsorbed on Pd-Au alloy surfaces show no evidence for an electronic effect of Au on Pd. The surface concentration of isolated Pd sites can be controlled by systematically altering the Pd-Au alloy composition, allowing detailed studies of isolated Pd sites as active sites for adsorption and reaction.