A theoretical study of CO adsorption on gold by Hückel theory and density functional theory calculations

Abstract

It is crucial to understand the nature of CO adsorption on gold so as to elucidate the mechanism of low-temperature CO oxidation on nanogold catalysts. We performed theoretical analysis of CO adsorption on gold by using Hückel theory and density functional theory (DFT) calculations. Hückel theory indicates that CO adsorption on gold is dominated by the electron distribution at the Au atom, which is greatly affected by neighboring Au atoms, coadsorbed or doping species. The increase of σ-bonding electrons should weaken the CO adsorption, while the increase of π-electrons should strengthen the adsorption. DFT calculations proved this prediction quantitatively for various systems, including CO adsorption on a Au(100)-hex surface with locally varying subsurface configurations and CO coadsorption with acceptor or donor species.