On the behaviour of structure-sensitive reactions on single atom and dilute alloy surfaces†
Materials that are composed of atomically dispersed platinum group metal (PGM) atoms on coinage metal surfaces show remarkable catalytic performance in a number of chemical reactions. On these single atom alloy (SAA) surfaces, the isolated PGM atoms exhibit unique reactivity features owing to their distinctive, and often limited, interactions with the surrounding coinage metal atoms. In this work, we use density functional theory to investigate the reactivity of numerous SAA(100) and (111) surfaces, focusing on typically structure-sensitive reactions, which include the direct dissociations of NO, CO2 and N2. Our results suggest that the structure-sensitivity of these three reactions is considerably reduced on SAA surfaces as compared to pure platinum group metal surfaces (Rh, Pt, Pd and Ni). Additionally, we examine the reactivity of small Rh and Ni ensembles doped on Cu(100) and (111) facets. We determine that Ni–Ni dimers and Ni trimers outperform the studied SAAs in the activation of NO, CO and NN bonds, and are also capable of performing facile association reactions. This work can guide future theoretical and surface science studies on SAAs, as well as the development of highly dilute alloys, which can efficiently catalyse chemistries of industrial significance.