The coverage of surface adsorbates influences both the number and types of sites available for catalytic reactions at a heterogeneous surface, but accounting for adsorbate-adsorbate interactions and understanding their implications on observed rates remain challenges for simulation. Here we demonstrate the use of a density-functional-theory (DFT) parameterized cluster expansion (CE) to incorporate accurate adsorbate-adsorbate interactions into a surface kinetic model. The distributions of adsorbates and reaction sites at a metal surface as a function of reaction conditions are obtained through Grand Canonical Monte Carlo simulations on the CE Hamiltonian. Reaction rates at those sites are obtained from the CE through a DFT-parameterized Br�nsted-Evans-Polyani (BEP) relationship or through a separate CE. The approach provides ready access both to steady-state rates and rate derivatives, and further provides insight into the microscopic factors that influence observed rate behavior. We demonstrate the approach for O2 temperature-programmed desorption and for steady-state O2 dissociation at an O-covered surface, for a range of metals.

Accurate coverage-dependence incorporated into first-principles kinetic models

243rd National Meeting (2012)

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