Hydrogen Spillover Mechanisms over a Graphite Surface

Four different mechanisms of hydrogen spillower over carbon surface are considered in the framework of a single quantum-chemical approach. Two of them, described in the literature, are the physical migration of a bonded hydrogen atom along the surface and the edge of the graphene. One of the mechanisms proposed by the author does not include the migration of atomic hydrogen, but is realized via a transfer of carbon radical over a carbon sheet and generation of H atom in another place. Calculated activation energies of all four mechanisms are compared.