First-principles kinetic Monte Carlo simulations for heterogeneous catalysis, applied to the CO oxidation at RuO2(110)

TL;DR

This paper presents a first-principles kinetic Monte Carlo simulation approach for heterogeneous catalysis, applied to CO oxidation on RuO2(110), accurately predicting surface structures, compositions, and reaction rates under various conditions.

Contribution

It introduces a comprehensive first-principles statistical mechanics method combining DFT, transition-state theory, and kinetic Monte Carlo for catalytic surface simulations.

Findings

Quantitative agreement with experimental data.

Identification of a disordered, dynamic surface phase.

Surface activity linked to compositional fluctuations.

Abstract

We describe a first-principles statistical mechanics approach enabling us to simulate the steady-state situation of heterogeneous catalysis. In a first step density-functional theory together with transition-state theory is employed to obtain the energetics of all relevant elementary processes. Subsequently the statistical mechanics problem is solved by the kinetic Monte Carlo method, which fully accounts for the correlations, fluctuations, and spatial distributions of the chemicals at the surface of the catalyst under steady-state conditions. Applying this approach to the catalytic oxidation of CO at RuO2(110), we determine the surface atomic structure and composition in reactive environments ranging from ultra-high vacuum (UHV) to technologically relevant conditions, i.e. up to pressures of several atmospheres and elevated temperatures. We also compute the CO2 formation rates (turnover frequencies). The results are in quantitative agreement with all existing experimental data. We find that the high catalytic activity of this system is intimately connected with a disordered, dynamic surface ``phase'' with significant compositional fluctuations. In this active state the catalytic function results from a self-regulating interplay of several elementary processes.