279418 DFT Predictions On the Kinetics and Bond Selectivity of Propane Activation On Palladium Oxide(101) Surface

Monday, October 29, 2012: 4:35 PM
318 (Convention Center )
Abbin Antony1, Aravind Asthagiri2 and Jason F. Weaver1, (1)Department of Chemical Engineering, University of Florida, Gainesville, FL, (2)Department of Chemical & Biomolecular Engineering, Ohio State University, Columbus, OH

Alkane activation on metal-based catalysts is of interest since it holds prospects as an energy source and in the production of value-added chemicals. Development of catalysts with high activity and precise selectivity is challenging due to the inertness of lower alkanes. In this talk, I will present results on dispersion-corrected density functional theory (DFT-D3) calculations of alkane activation on the PdO(101) surface. Dispersion corrections are found to improve binding energy predictions of alkane sigma-complexes on PdO(101), yielding values that compare well with experimental estimates. The calculations also predict a strong preference for propane to undergo primary C-H bond activation on PdO(101) which is consistent with experimental studies (90% of the chemisorbed C3H8 which reacts experimentally does so by primary C-H bond cleavage) but contrary to the thermodynamic preference for homolytic C-H bond cleavage (tertiary > secondary >  primary). Charge density analysis indicates that alkane activation on PdO(101) is heterolytic in nature and suggests that the high selectivity for primary C-H bond activation of C3H8 on PdO(101) results in part from greater polarization within the 1-propyl transition structures. We find that propane molecules also have a higher probability of initially populating molecular configurations in which primary C-H bonds interact strongly with the surface. I will also present results of a micro kinetic model used to evaluate the kinetic competition among reaction pathways available to adsorbed propane complexes and predict kinetic information that is comparable with experimental data.

Extended Abstract: File Not Uploaded
See more of this Session: Computational Catalysis II
See more of this Group/Topical: Catalysis and Reaction Engineering Division