Lanthanide Atoms Induce Strong Graphene Sheet Distortion When Adsorbed on Stone-Wales Defects.

Local curvature in graphene can enhance its reactivity and catalytic activity and can be induced by the adsorption of certain chemical species. By employing periodic density functional theory (DFT) calculations, we demonstrate that significant local curvature can be systematically observed when lanthanide atoms (the full series from La to Lu) are adsorbed on the Stone-Wales (SW) defect in graphene, contrary to that in defect-free graphene. Despite the typical high coordination numbers of lanthanide species, their hapticity is always η (and not η, η, or η), where Ln atoms are adsorbed on the (7,7) junction, forming relatively short Ln···C separations.

Strong Bending Distortion of a Supercoronene Graphene Model upon Adsorption of Lanthanide Atoms.

Numerous applications of graphene involve quasi-infinite sheets, as well as finite structures with edges, pores, graphene quantum dots, etc. In theoretical studies of adsorption of diverse chemical species, including single atoms, molecules, cations, and anions, graphene usually behaves as a very rigid planar structure. However, we found that when adsorbing lanthanide atoms, finite size structures, represented by the widely used supercoronene model, can undergo considerable distortion, and the degree of distortion depends on the number of unpaired electrons, reaching a maximum for Gd (eight unpaired electrons).

Adsorption of Lanthanide Atoms on Graphene: Similar, Yet Different.

Many theoretical studies address the interaction of different atoms with graphene; however, the relevant information on the adsorption of the lanthanide species remains limited and controversial, creating a gap in this important area of graphene chemistry and physics. By employing periodic density functional theory calculations, we provide the key theoretical information for the entire series from lanthanum to lutetium interacting with defect-free graphene, including the interaction strength and distances, charge and spin of the lanthanide atoms, and comparative features of the density of states. The central lanthanides Gd, Tb, and Dy exhibit the strongest bonding and shortest distances.

A dispersion-corrected density functional theory study of the noncovalent interactions between nucleobases and carbon nanotube models containing stone-wales defects.

The noncovalent bonding between nucleobases (NBs) and Stone-Wales (SW) defect-containing closed-end single-walled carbon nanotubes (SWNTs) was theoretically studied in the framework of density function theory using a dispersion-corrected functional PBE-G06/DNP. The models employed in this study were armchair nanotube (ANT) (5,5) and zigzag nanotube (ZNT) (10,0), which incorporated SW defects in different orientations. In one of them, the (7,7) junction is tilted with respect to SWNT axis (ANT-t and ZNT-t), whereas in ANT-p and ZNT-p models the (7,7) junction is parallel and perpendicular to the axis, respectively.