DFT study of the effect of Al2O3 support on Pt catalytic activity

COMP 231

Jennifer Synowczynski, jenns@arl.army.mil, Weapons and Materials Research Directorate, U. S. Army Research Laboratory, Aberdeen Proving Grounds, MD 21005, Jan Andzelm, jandzelm@arl.army.mil, Materials Division, Multifunctional Materials Branch, U. S. Army Research Laboratory, Building 4600, Aberdeen Proving Ground, MD 21005-5069, and Dionisios G. Vlachos, vlachos@udel.edu, Center for Catalytic Science and Technology, Department of Chemical Engineering, University of Delaware, Colburn lab, 150 Academy Street, Newark, DE 19716.
Alumina supported catalytic Pt-nanoclusters have been used to promote a variety of reactions including the steam reforming of methane and Fischer-Tropsch synthesis. Understanding the influence of the Pt/Al2O3 interface is key to facilitating combustion reactions in small scale reactors. Although there are many computational studies which detail the complete reaction mechanism for reactant and product species interacting with the catalytically active metal-cluster, few studies consider the pathways that arise due to presence of the Pt/Al2O3 interface. In this paper, we first study the chemisorption of small Pt clusters on Al(100) surface and identify two unique adsorption structures for Pt trimer clusters and three adsorption structures for atomic Pt. We then investigated the thermochemistry and kinetics for dissociation and surface diffusion processes involving small molecular fragments such as water, hydroxyl, hydrogen and oxygen molecules on both the support and at the support/metal interface. The reaction barriers for dissociation and diffusion processes were calculated using the Density Functional Theory (DFT)- Generalized Gradient Approximation (GGA) and compared to experimental data, when available.
 

Poster Session
6:00 PM-8:00 PM, Tuesday, August 18, 2009 Walter E. Washington Convention Center -- Ballroom A, Poster

Division of Computers in Chemistry

The 238th ACS National Meeting, Washington, DC, August 16-20, 2009