280488 A First-Principles Study On Carbon Dioxide Reforming of Methane Over Supported Pt Catalysts

Tuesday, October 30, 2012: 5:15 PM
318 (Convention Center )
Zhuo Cheng1, Vesna Havran1, Nathan A. Fine1,2, Brent Sherman1,2 and Cynthia S. Lo1, (1)Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, (2)Chemical Engineering, University of Texas at Austin, Austin, TX

Synthesis of fuels and chemicals via dry reforming of carbon dioxide and methane, which are both greenhouse gases, has the vast potential for closing the carbon cycle and providing clean energy. For this reason, much effort has been dedicated to exploring efficient ways for the reduction of CO2 and the dehydrogenation of CH4 into small building block for use in syngas chemistry. Pt/Silica and Pt/Ceria are promising catalysts for dry reforming due to the reactivity at the metal-support interface. In this study, we use first-principles density functional theory and Kinetic Monte Carlo method to investigate the details of the adsorption and reaction process on these two supported catalyst systems. We found that CO2 prefers to be adsorbed, with OCO angle of 136.9, onto reduced Ceria (110) to form the active carbonate unit [(CO3)2-] as the first step in CO2 reduction, while CH4 prefers to dehydrogenate via Pt nanoclusters.  Also, we found that the shape of Pt cluster is vitally important in controlling catalytic activity, and the use of faceted catalyst particles opens up possibilities for low-temperature and energy-efficient hydrocarbon transformations. We map the dry reforming pathway by identifying the reaction intermediates and transition states, and calculating the energy barriers. The results obtained advance our fundamental understanding of the dry reforming mechanisms, and provide a design strategy for the simultaneous reduction of CO2 and the dehydrogenation of CH4 on supported Pt catalysts.

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