Cluster size effects on the adsorption of CO, O, and CO2 and the dissociation of CO2 on two-dimensional Cu x (x = 1, 3, and 7) clusters supported on Cu(111) surface: a density functional theory study

Abstract

In this study, we performed density functional theory (DFT) based calculations to determine the effect of the size of Cu_x (x = 1 (adatom), 3 (trimer), 7 (heptamer)) cluster supported on Cu(111) toward the adsorption of CO, O, and CO₂, and the dissociation of CO₂. CO adsorbs with comparable adsorption energies on the different cluster systems, which are influenced by the reactivity of the Cu atoms in the cluster and the interaction of CO with the Cu atoms in the terrace. O atom, on the other hand, will always favor to adsorb on hollow sites and is more stable on hollow sites of smaller clusters. CO₂ dissociates with lower activation energy on the cluster region than on flat Cu(111). We obtained the lowest activation energy on Cu₃ due to its more reactive Cu atoms than the Cu₇ case, and due to the possibility of O to adsorb on the cluster region which is not observed for the Cu₁ case. The presented results will provide insights on future studies on supported cluster systems and on their possible use as catalysts for CO₂-related reactions.