Towards a first-principles chemical engineering: Transport limitations and bistability in in situ CO oxidation at RuO2(110)

TL;DR

This paper introduces a multiscale modeling approach combining first-principles kinetics and fluid dynamics to study CO oxidation on RuO2(110), revealing transport effects and bistability that impact catalyst reactivity interpretation.

Contribution

It develops a novel integrated modeling framework that captures transport limitations and multiple steady-states in heterogeneous catalysis under realistic conditions.

Findings

Heat and mass transfer can mask intrinsic reactivity.

Multiple steady-states arise from transport-kinetics coupling.

Transport effects are crucial for interpreting in situ experiments.

Abstract

We present a first-principles based multiscale modeling approach to heterogeneous catalysis that integrates first-principles kinetic Monte Carlo simulations of the surface reaction chemistry into a fluid dynamical treatment of the macro-scale flow structures in the reactor. The approach is applied to a stagnation flow field in front of a single-crystal model catalyst, using the CO oxidation at RuO2(110) as representative example. Our simulations show how heat and mass transfer effects can readily mask the intrinsic reactivity at gas-phase conditions typical for modern in situ experiments. For a range of gas-phase conditions we furthermore obtain multiple steady-states that arise solely from the coupling of gas-phase transport and surface kinetics. This additional complexity needs to be accounted for when aiming to use dedicated in situ experiments to establish an atomic-scale understanding of the function of heterogeneous catalysts at technologically relevant gas-phase conditions.