AVS 61st International Symposium & Exhibition
    Nanometer-scale Science and Technology Wednesday Sessions
       Session NS-WeM

Paper NS-WeM5
Size-dependent Trends in CO and O2 Adsorption on Pd Nanoparticle Catalysts

Wednesday, November 12, 2014, 9:20 am, Room 304

Session: Nanoscale Catalysis and Surface Chemistry  
Presenter: Hemma Mistry, University of Central Florida
Authors: H. Mistry, University of Central Florida
L.K. Ono, University of Central Florida
B. Roldan Cuenya, Ruhr-University Bochum, Germany
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Due to the striking dependence of many catalytic reactions on particle size and shape, a thorough understanding of structure-dependent reactivity trends in the interaction of adsorbates with model nanoparticles (NPs) is key to designing highly active and selective catalysts. Palladium NPs are highly active for important reactions such as CO oxidation and methane combustion. However, conflicting reports exist in the literature on the change in CO and O2 adsorption strength on Pd NPs of different size. In this study, temperature programmed desorption (TPD) was used to investigate the binding strength of O and CO on Pd NPs supported on SiO2/Si(111). A range of clusters with Pd deposition thicknesses between 1.5 and 15 Å were investigated and compared to Pd(111). Our results indicate that both O and CO binding strength increase dramatically with decreasing particle size, and the presence of distinct binding sites on the smaller NPs was revealed by CO TPD.