Mechanism of Metal Catalyzed Healing of Large Structural Defects in Graphene

Structural defects are almost unavoidable in graphene synthesis and they may significantly deteriorate the performance of graphene in applications. Although defects of small sizes may be easily healed by the rearrangement of a few C atoms near the defect site, the healing of large ones is rather complicated and the healing mechanism remains unclear. In this work, we reveal a catalytic healing of large structural defects in graphene based on both classical molecular dynamics simulations and density functional theory calculations. The kinetic healing processes of large vacancy holes in graphene with and without a nickel catalyst are explored. Our results show that the presence of a single Ni atom can (1) catalyze the dissociation of carbon feedstock, (2) heal nonhexagonal C rings formed during the addition of C atoms, and (3) prevent the formation of hanging C chains and arching C patches, and ultimately lead to the successful healing of large structural defects in graphene.