Stabilizing single atoms and a lower oxidation state of Cu by a ½[110]{100} edge dislocation in Cu-CeO₂

Abstract

Stabilizing atomically dispersed catalytic metal species at surfaces is a significant challenge for obtaining high-performance single atom catalysts. This is because of the strong tendency for the dispersed metal atoms to agglomerate. We propose that dislocations can provide a strong anchor for stabilizing single atoms. A ½[110]{100} edge dislocation in Cu doped ceria, Cu-CeO₂, is investigated as a model system with density functional theory. The defect formation energies are found to be lower at the dislocation core, with a large segregation energy ranging within 0.8–2.5 eV depending on the site and species at the dislocation core. The high segregation energy indicates that the edge dislocations can enrich Cu defects in an atomically sized area and, thus, have a potential to strongly anchor single atom species at surfaces. Moreover, the edge dislocation also stabilizes reduced cation species, Cu (1+) and Ce (3+). The more reduced dislocation core can offer high concentration of oxygen vacancy as well as in-gap electronic states which provide more reactivity for surface reactions.