Composition and structure of the RuO2(110) surface in an O2 and CO environment: implications for the catalytic formation of CO2

TL;DR

This study uses density-functional theory and thermodynamics to analyze the surface structures of RuO2(110) in O2 and CO environments, providing insights into catalytic CO2 formation and surface dynamics.

Contribution

It presents a detailed phase diagram of RuO2(110) surfaces under realistic conditions and explores reaction pathways, highlighting the role of phase coexistence in catalysis.

Findings

Adsorption depends on temperature and gas partial pressures.

Surface phase coexistence enhances surface dynamics.

Reaction pathways and energy barriers were calculated.

Abstract

The phase diagram of surface structures for the model catalyst RuO2(110) in contact with a gas environment of O2 and CO is calculated by density-functional theory and atomistic thermodynamics. Adsorption of the reactants is found to depend crucially on temperature and partial pressures in the gas phase. Assuming that a catalyst surface under steady-state operation conditions is close to a constrained thermodynamic equilibrium, we are able to rationalize a number of experimental findings on the CO oxidation over RuO2(110). We also calculated reaction pathways and energy barriers. Based on the various results the importance of phase coexistence conditions is emphasized as these will lead to an enhanced dynamics at the catalyst surface. Such conditions may actuate an additional, kinetically controlled reaction mechanism on RuO2(110).