CO Dissociation Mechanism on Pd-Doped Fe(100): Comparison with Cu/Fe(100)

Abstract

Spin-polarized density functional theory computations have been used to investigate the CO dissociation mechanisms and the different catalytic activities of the reaction on Fe(100) surfaces with different Pd coverages. CO can dissociate on Pd/Fe surfaces via three different mechanisms: direct and H-assisted mechanisms via HCO intermediate or COH intermediate. In our calculation, it was found that the activation barriers of direct CO and COH dissociation mechanisms on pure and Pd-doped Fe(100) surfaces were higher than that of the HCO dissociation mechanism. Besides, energy barriers for the identical reaction pathway on Fe-rich Fe(100) surfaces were lower than those on Pd-rich Fe(100) surfaces, namely, CO dissociation mainly occurs via the HCO intermediate pathway and the catalytic activity becomes lower with Pd coverage increasing toward CO dissociation in both direct CO and H-assisted CO dissociation mechanisms. As a result, CO dissociation mainly occurs on Fe-rich Pd/Fe surfaces, leading to the formatio...