Theoretical investigation of the anchoring and activity of a gold cluster on two-dimensional substrates

Gold nanoparticles can be used as catalysts in several chemical reactions. However, when mobile on a substrate gold nanoparticles coalesce, increasing their diameter, and reducing their catalytic properties. In this work, we performed density functional theory calculations to study the interaction of a 34 atoms gold cluster with different two-dimensional materials: pristine graphene, defective graphene (single vacancy), hexagonal boron nitride, tungsten diselenide and thiophenol functionalized graphene. An analysis of the bond strength between the gold cluster and the two-dimensional substrates shows a diverse scenario, from non-bonding or slight repulsive interactions to strong bonded cases. The examination of the band edge levels of the interacting systems (gold cluster + two-dimensional substrates) indicates that the catalytic activity of the gold cluster depends on the particular two-dimensional substrate on which it is deposited. We find that a clean non-functionalized two-dimensional substrate, the tungsten diselenide, can firmly anchor the gold cluster, and that in this situation the cluster will present an amphoteric behavior.