Predictive Beyond-Mean-Field Rate Equations for Multisite Lattice–Gas Models of Catalytic Surface Reactions: CO Oxidation on Pd(100)

File

2016-GordonMark-PredictiveBeyond.pdf (1.33 MB)

Date

2016-12-22

Authors

Gordon, Mark
Evans, James
Gordon, Mark S.
Evans, James W.

Publisher

American Chemical Society

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Authors

Gordon, Mark

Person

Evans, James

Person

Organizational Units

Chemistry

Organizational Unit

Ames Laboratory

Organizational Unit

Mathematics

Organizational Unit

Physics and Astronomy

Organizational Unit

Department

ChemistryAmes LaboratoryMathematicsPhysics and Astronomy

Abstract

Tailored multisite lattice–gas (msLG) models are developed for CO oxidation on Pd(100) at low-pressures. These models include multiple adsorption site types and superlattice adlayer ordering due to short-range exclusion for highly mobile reactant adspecies. However, they are simplified to neglect longer-range weaker adspecies interactions, so that the key energetic parameters are the CO desorption barrier and the reaction barrier. We discuss existing density functional theory results for these energies and present additional analysis for CO adsorption. After also including an appropriate nontrivial specification of the dynamics of adsorption onto mixed reactant adlayers, we develop rate equations for the reaction kinetics. Our formulation goes beyond traditional mean-field (MF) Langmuirian treatments by accounting for multiple adsorption sites and for the strong spatial correlations associated with superlattice ordering. Specifically, we utilize factorization approximations based on appropriate site motifs, and also Padé resummation of exact low-coverage expansions for sticking coefficients. Our beyond-MF rate equations are successful in accurately predicting key aspects of reactive steady-state behavior, and thus expand the utility of rate equation formulations in surface chemistry. This is confirmed by comparison with precise kinetic Monte Carlo simulation results. Specifically, we not only assess bistability and criticality observed for CO oxidation but also find more complex multistability associated with symmetry-breaking transitions in high-coverage CO adlayers.

Comments

This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in The Journal of Physical Chemistry C, copyright © 2016 American Chemical Society after peer review. To access the final edited and published work see DOI: 10.1021/acs.jpcc.6b10102. Posted with permission.