Adsorption and Activation of n-Alkanes On a Pdo(101) Thin Film

Monday, October 17, 2011: 12:30 PM
200 B (Minneapolis Convention Center)
Jason F. Weaver1, Aravind Asthagiri2, Jose Hinojosa Jr.3, Can Hakanoglu1, Abbin Antony1 and Jeffery M. Hawkins1, (1)Chemical Engineering, University of Florida, Gainesville, FL, (2)Department of Chemical & Biomolecular Engineering, The Ohio State University, Columbus, OH, (3)Department of Chemical Engineering, University of Florida, Gainesville, FL

The formation of palladium oxide (PdO) is thought to be responsible for the exceptional activity of supported Pd catalysts toward the complete oxidation of alkanes under oxygen-rich conditions. In this talk, I will discuss our recent investigations of the adsorption and activation of n-alkanes on a PdO(101) thin film that is prepared by oxidizing Pd(111) in ultrahigh vacuum (UHV) using an oxygen atom beam. We find that alkanes adsorb relatively strongly on the PdO(101) surface by forming σ-complexes along the rows of coordinatively unsaturated (cus) Pd atoms, and that this adsorbed state acts as the precursor for initial C-H bond cleavage. For example, propane and n-butane undergo facile C-H bond cleavage on PdO(101) below about 215 K in UHV. I will also discuss density functional theory calculations which show that dative bonding between the alkane and cus-Pd atoms weakens the coordinated C-H bonds, thereby lowering dissociation barriers significantly. Finally, I will discuss recent results on C-H bond selectivity in the initial activation of propane on PdO(101) as well as the activity of binary Pd-M oxides toward alkane activation.

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See more of this Session: Computational Catalysis II
See more of this Group/Topical: Catalysis and Reaction Engineering Division