Facile abstraction of hydrogen atoms from graphane, diamond, and amorphous carbon surfaces: A first-principles study

ion of surface hydrogen by atomic H from graphane, diamond 001 , diamond 111 , and hydrogenated amorphous carbon a-C:H surfaces was studied using density-functional theory calculations in the generalized gradient approximation. Our calculations show that for each surface, the abstraction reaction is highly exothermic with a negligible activation energy barrier. The degree of exothermicity depends on the type of surface and on the local bonding environment of the site from which the H atom was abstracted. Detailed analyses of the reactions and of atomic charge densities along reaction pathways indicate a direct-impact Eley-Rideal mechanism for the abstractions. DOI: 10.1103/PhysRevB.82.085418 PACS number s : 82.65. r