(175b) Estimating Reaction Rates from Coverage Dependent Binding Energies

Creating accurate, compact rate models from first principles simulations remains a challenge in computational catalysis. Given a microkinetic description of all the steps in a catalytic mechanism and their sensitivity to their local surface environment, macroscopically observable rates can be rigorously estimated by suitable averaging over the microscopic rates, for instance using kinetic Monte Carlo.  This approach can be further simplified by using the variation in apparent surface energetics as an estimator of microscale behavior, allowing for good fidelity using only an excess energy representation for surface species and a Brønsted–Evans–Polanyi (BEP) relationship to correlate overall reaction energies to energies of activation.  In this work, density functional theory calculations are used to parameterize excess energy descriptions of adsorbates on a Pt (111) surfaces. These descriptions are used in conjunction with BEP relations to provide a steady-state description of catalytic oxidation networks. Results are compared with equivalent descriptions of the oxidation networks derived from Monte Carlo simulations and weighted distribution sampling.