Lanthanide Atoms\nInduce Strong Graphene Sheet Distortion\nWhen Adsorbed on Stone–Wales Defects

Local curvature in graphene can enhance its reactivity\nand catalytic\nactivity and can be induced by the adsorption of certain chemical\nspecies. By employing periodic density functional theory (DFT) calculations,\nwe demonstrate that significant local curvature can be systematically\nobserved when lanthanide atoms (the full series from La to Lu) are\nadsorbed on the Stone–Wales (SW) defect in graphene, contrary\nto that in defect-free graphene. Despite the typical high coordination\nnumbers of lanthanide species, their hapticity is always η<sup>2</sup> (and not η<sup>5</sup>, η<sup>6</sup>, or η<sup>7</sup>), where Ln atoms are adsorbed on the (7,7) junction, forming\nrelatively short Ln···C separations. Contrary to the\npristine graphene, the SW region undergoes considerable distortion\nand results in much stronger Ln bonding. The positive charge acquired\nby Ln atoms upon adsorption on SW is approximately 1.5 times larger\nthan that on defect-free graphene. The high visibility of electron-rich\nlanthanide species in scanning tunneling microscopy images provides\na means to locate SW defects in graphene samples experimentally.