Title: First-Principles Modeling of Chemical Reactions on Heterogeneous Catalysts: Fundamental Understanding and Catalyst Design

Speaker: Jeff Greeley, Center for Atomic-scale Materials Physics, Department of Physics Technical University of Denmark

Date/Time: Wednesday, May 18, 2005, 1:30-2:30 pm

Location: Building 980, Room 95 (Sandia NM)

Brief Abstract: First-principles, quantum-based simulations of elementary chemical processes are emerging as a powerful tool for the analysis and design of heterogeneous, transition metal catalysts.  These simulations can provide detailed, molecular-level information about the energies, geometries, and electronic structures of chemical species on metal surfaces.  This information, which is often inaccessible through experiment alone, permits the determination of catalytically-relevant quantities such as adsorption energies, adsorbate entropies, and activation barriers of elementary reaction steps.  A thorough understanding of these important catalytic parameters can, in turn, be used as a starting point for the first-principles design of new catalysts. In this talk, I present two illustrations of the use of first-principles calculations to analyze chemical reactions on heterogeneous catalysts.  The first example, of relevance to the study of anodes for direct methanol fuel cells, focuses on the development of fundamental understanding of the methanol decomposition reaction mechanism on Pt(111).  The second example, of interest for a broad variety of catalytic processes involving oxygen, demonstrates how a first-principles approach can be used as a preliminary screening technique for new catalysts.  For the latter example, two screening methodologies are illustrated.  First, the development of databases of catalytic parameters for a significant number of binary metal alloys is described, and second, the use of evolutionary algorithms to screen a large search space of quaternary metal alloys is discussed.  The application of both methodologies to important problems in catalysis and electrocatalysis is examined.