Using density functional theory calculations, a strategy was investigated for the easy hydrogenation of graphene. It was shown that the presence of polar hydride molecules, such as H2O, HF and NH3 (physisorbed molecules that mediate/assist the migration of atomic H adatoms on graphene, here termed shuttle gases), could provide a favorable catalytic effect (lowering the H migration barrier) and a favorable thermodynamic effect (activating the direct transition to the second-nearest-neighbor site). In comparison with the widely known fact that the migration of chemisorbed H was kinetically unfavorable on graphene, this mechanism for shuttling catalysis provides an easier migration channel. It was proposed that randomly distributed hydrogen adatoms on graphene could transform into a compactly aggregated hydrogenation domain (similar to graphane, as suggested in the literature) by heat treatment in the presence of a shuttling catalyst.

Effect of Shuttling Catalyst on the Migration of Hydrogen Adatoms: a Strategy for the Facile Hydrogenation of Graphene. Han, S.S., Kim, H., Park, N.: Journal of Physical Chemistry C, 2011, 115[50], 24696-701