Strong adsorption between uranium dicarbide and graphene surface induced by f electrons

The interaction between gaseous uranium dicarbide and graphite is significant for the safety control and design of Gen-IV nuclear energy system. In this article, the interaction mechanism has been studied using a simplified model of adsorption of two typical UC₂ isomers (linear CUC and symmetric triangular structures) on graphene based on density functional theory calculations. The results reveal strong chemisorption characteristics between the UC₂ and graphene, which is found to be different from the conventional weak intermolecular interaction. Interestingly, although the CUC structure can induce a double sp³-hybridization at the graphene, the most stable adsorption structure is formed by the triangular UC₂ adsorbed at the hollow site of the graphene. Further bonding analysis indicates that the U 5f orbitals of the triangular UC₂ are more active than that in the CUC, providing a larger effective bonding area in the adsorption system. Our calculations are helpful for understanding the role of actinide compounds in adsorption on carbon nanomaterials surface, especially for elucidating the bonding properties of 5f electrons. © 2013 American Chemical Society.