Role of Small Pd Ensembles in Boosting CO Oxidation in AuPd Alloys

Title
Role of Small Pd Ensembles in Boosting CO Oxidation in AuPd Alloys
Authors
함형철J. Adam StephensGyeong S. Hwang한종희남석우임태훈
Keywords
CO oxidation; PdAu alloy; Pd ensembles
Issue Date
2012-03
Publisher
Journal of Physical Chemistry Letters
Citation
VOL 3, NO 5, 566-570
Abstract
We present a theoretical explanation on how PdAu alloy catalysts can enhance the oxidation of CO molecules based on density functional theory calculations of CO adsorption and oxidation on AuPd/Pd(111) surfaces. Our study suggests that the enhanced activity is largely attributed to the possible existence of “partially-poisoned” Pd ensembles that accommodate fewer CO molecules than Pd atoms. Whereas the oxidation of preadsorbed CO is likely governed by O2 trapping, our study shows that small Pd ensembles such as dimers and compact trimers tend to provide more active sites than larger ensembles; CO adsorbed on a Pd monomer is found to react hardly with O2 to form CO2. In addition, we find the tendency of COinduced Pd agglomeration, which may in turn facilitate CO oxidation by creating more dimers and compact trimers as compared with the adsorbate-free surface where monomers are likely prevailing.
URI
http://pubs.kist.re.kr/handle/201004/42103
ISSN
19487185
Appears in Collections:
KIST Publication > Article
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