DFT Study of Support Effects for O2 Dissociation on Cu5 Clusters: Opposite Trends in N-doped Graphene Compared to CeO2(111)

[EN] The metal-support interaction (MSI) effect of different supports, namely, N-doped graphene (N-graphene) and CeO2(111), on the properties of the planar 2D and 3D isomers of copper clusters of atomicity five was computationally studied at the PBE level (+U for Ce). For graphene-based systems, both pristine and defective sheets were considered. The stability, geometry and electronic properties of the supported Cu-5 clusters are discussed, and the dissociation of O-2 is studied on the most stable systems for both isomers. As expected, the interaction between Cu-5 and clean graphene or N-graphene is weak, and although adding nitrogen to graphene enhances the interaction, proper chemical adsorption is only achieved on the defects explored. In contrast, both Cu-5 isomers interact strongly with CeO2(111). The weaker MSI with N-graphene materials allows the deformation of the Cu-5 cluster upon O-2 adsorption, whereas CeO2(111) supported structures are more robust. O-2 dissociation on N-graphene-supported Cu-5 is consistent with our previous results on gas-phase clusters, i.e. the 2D isomer is more resistant to oxidation than the 3D one but the latter is more easily reducible, while on CeO2(111) this trend is reversed due to the strong MSI.