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 the relevant elementary processes. Subsequently the statistical mechanics problem is solved by the kinetic Monte Carlo method, which 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 $\mathrm{Ru}{\mathrm{O}}_{2}(110)$, 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 $\mathrm{C}{\mathrm{O}}_{2}$ 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.
Highlights
Rational design and advancement in materials science will rely on an atomic-scale understanding of the targeted functionality
In a recent letter we presented a first-principles statistical mechanics setup suitable to tackle this challenge,[3] and in this paper we give a detailed account of the employed methodology
In summary we have presented a first-principles statistical mechanics approach to quantitatively study the steady-state situation of heterogeneous catalysis
Summary
Rational design and advancement in materials science will rely on an atomic-scale understanding of the targeted functionality. An additional level of complexity is encountered when aspiring a predictive, quantitative modeling that is based on understanding, and that is applicable to realistic environmental situations of varying temperatures and pressures This excludes the use of empirical or fitted parameters, in which often several not-further-specified processes are effectively “lumped together,” and excludes the use of a mean-field description as, e.g., microkinetic rate equation approaches.[2] As we will further qualify below, parameters with clear microscopic meaning and an explicit consideration of the correlations, fluctuations, and spatial distributions of the chemicals at the catalyst surface are crucial to properly understand and potentially rationally design macroscopic catalytic functionality. This two-step approach enables us to gain microscopic insight into the system, following its full dynamics from picoseconds up to seconds. III to analyze the surface composition and structure, showing that high catalytic activity in this system is intimately connected with a disordered and dynamic “phase” at the surface, in which the observable catalytic function results from the self-regulating action of several different elementary processes
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
