Structure Sensitivity in Oxide Catalysis: First-Principles Kinetic Monte Carlo Simulations for CO Oxidation at RuO$_2$(111)

TL;DR

This study uses first-principles kinetic Monte Carlo simulations to compare CO oxidation on RuO$_2$(111) and RuO$_2$(110) facets, revealing that despite microscopic differences, their catalytic activities are similar under relevant conditions, questioning traditional structure sensitivity concepts.

Contribution

The paper provides the first detailed comparison of elementary processes and catalytic activity between RuO$_2$(111) and RuO$_2$(110) facets using density-functional theory based kinetic Monte Carlo simulations.

Findings

Both facets show similar catalytic activity at elevated temperatures and near-ambient pressures.

Significant differences exist in binding energetics and elementary process interplay.

Traditional structure sensitivity classifications may not apply to oxide catalysis.

Abstract

We present a density-functional theory based kinetic Monte Carlo study of CO oxidation at the (111) facet of RuO$_2$. We compare the detailed insight into elementary processes, steady-state surface coverages and catalytic activity to equivalent published simulation data for the frequently studied RuO$_2$(110) facet. Qualitative differences are identified in virtually every aspect ranging from binding energetics over lateral interactions to the interplay of elementary processes at the different active sites. Nevertheless, particularly at technologically relevant elevated temperatures, near-ambient pressures and near-stoichiometric feeds both facets exhibit almost identical catalytic activity. These findings challenge the traditional definition of structure sensitivity based on macroscopically observable turnover frequencies and allow to scrutinize the applicability of structure sensitivity classifications developed for metals to oxide catalysis.