Density functional theory (DFT) investigation of the adsorption of the CH₃OH/Au(100) system

Abstract

The adsorption of methanol on flat Au (100) surface with different coverages (θ = 1.0, 0.5 and 0.25 monolayer (ML)) is studied using density functional theory. Among the three sites (top, bridge and hollow) and coverages investigated in the present work, no adsorption is stable for θ = 1.0 ML. The most energetically preferred site of adsorption for CH 3 OH is found to be the hollow site for coverages of 0.25 ML and 0.50 ML. We also find that for all adsorption sites, an increase in CH 3 OH coverage triggers a decrease in the adsorption energy. The geometric parameters, local density of states and work function changes are analysed in detail. The coadsorption of methoxy and hydrogen has also investigated. In addition, the dissociation of methanol on Au(100) has been studied, and an activation energy was found to be 1.72 eV. This result compare with existing data in the literature for Au(111) surface.