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First principles adaptive kinetic Monte Carlo calculations of catalytic reactions at supported nanoparticles


EMSL Project ID
25428

Abstract

The goal of this project is to use density functional theory calculations to discover the mechanisms and rates of catalytic reactions on oxide supported metal surfaces and nanoparticles. The focus will be on reactions that are important for hydrogen production, including steam reforming of methanol, the water-gas shift reaction, and preferential oxidation of CO. A comparison of rate limiting steps will be made between crystal facets of Pt and Cu, and compared with nanoparticles of these metals supported on CeO2. The specific aim of this proposal is to implement and apply new computational methodology at the EMSL for finding reaction mechanisms and using the calculated rates to simulate the reaction dynamics of adsorbed molecules. To do this, we will use the dimer min-mode following saddle point finding method [1], implemented in the Vienna Ab-Initio Software Package (VASP), to search for possible reaction mechanism. These calculations will not be restricted to expected reaction mechanisms; instead, through many random searches, the method will automatically discover which reactions are most likely to happen. The submission of these calculations, as well as the collection of the resulting data will be done with an automated perl script [2]. When this script learns about the possible reaction mechanisms, it does a kinetic Monte Carlo step, and the saddle point finding process is repeated. In this way, the unbiased reaction dynamics of the molecules will be simulated, and the mechanism of catalytic reactions at nanoparticles is explored.

[1] See http://theory.cm.utexas.edu/vtsttools/dimer/
[2] See http://theory.cm.utexas.edu/vtsttools/akmc/

Project Details

Project type
Large-Scale EMSL Research
Start Date
2007-05-22
End Date
2010-09-30
Status
Closed

Team

Principal Investigator

Graeme Henkelman
Institution
University of Texas at Austin

Team Members

Gopi Krishna Phani Dathara
Institution
University of Texas at Austin

Wenjie Tang
Institution
University of Virginia

Rye Terrell
Institution
University of Texas at Austin

Donghai Mei
Institution
Tiangong University

Lijun Xu
Institution
University of Virginia

Related Publications

Lijun Xu, Donghai Mei, and Graeme Henkelman "Adaptive kinetic Monte Carlo simulation of methanol decomposition on Cu(100)" J. Chem. Phys. (2009) under review.
L. Xu, D. Mei, and G. Henkelman Adaptive kinetic Monte Carlo simulation of methanol decomposition on Cu(100), J. Chem. Phys. 131, 244520 (2010).
Mei D, L Xu, and GA Henkelman. 2008. "Dimer Saddle Point Searches to Determine the Reactivity of Formate on Cu(111)." Journal of Catalysis 258(1):44-51.