CO Dissociation Mechanism on Cu-Doped Fe(100) Surfaces

Abstract

Periodic density functional theory calculations were carried out to investigate CO dissociation pathways on the Fe(100) surfaces covered with up to one monolayer of Cu atoms, which serve as the simple models for the Cu/Fe catalysts for higher alcohol synthesis (HAS) from syngas. For all the model catalyst surfaces, H-assisted CO dissociation was predicted to have lower energy barriers than direct CO dissociation. The difference in the energy barriers between the two dissociation pathways increases as Cu surface coverage increases, suggesting reduced contribution of direct CO dissociation on Cu-rich surfaces. A further thermodynamic analysis also reaches the same conclusion. Several reaction properties for CO dissociation, including CO physisorption and chemisorption energies, and energy barriers for direct and H-assisted CO dissociations, were found to scale linearly with Cu surface coverage, and these reaction properties were predicted to depend largely on the structure of the surface layer, which can be...