Role of small Pd ensembles in boosting CO oxidation in AuPd alloys

Hyung Chul Ham, J. Adam Stephens, Gyeong S. Hwang, Jonghee Han, SukWoo Nam, Tae Hoon Lim

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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 O 2 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 O 2 to form CO 2. In addition, we find the tendency of CO-induced 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.

Original languageEnglish
Pages (from-to)566-570
Number of pages5
JournalJournal of Physical Chemistry Letters
Volume3
Issue number5
DOIs
Publication statusPublished - 2012 Mar 1
Externally publishedYes

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ASJC Scopus subject areas

  • Materials Science(all)

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