title: Oxygen Intercalation of Graphene on Transition Metal Substrate: An Edge-Limited Mechanism.
abstract: Oxygen intercalation has been proven to be an efficient experimental approach to decouple chemical vapor deposition grown graphene from metal substrate with mild damage, thereby enabling graphene transfer. However, the mechanism of oxygen intercalation and associated rate-limiting step are still unclear on the molecular level. Here, by using density functional theory, we evaluate the thermodynamics stability of graphene edge on transition metal surface in the context of oxygen and explore various reaction pathways and energy barriers, from which we can identify the key steps as well as the roles of metal passivated graphene edges during the oxygen intercalation. Our calculations suggest that in well-controlled experimental conditions, oxygen atoms can be easily intercalated through either zigzag or armchair graphene edges on metal surface, whereas the unwanted graphene oxidation etching can be suppressed. Oxygen intercalation is, thus, an efficient and low-damage way to decouple graphene from a metal substrate while it allows reusing metal substrate for graphene growth.
authors.affiliation: Department of Physics, Southeast University , Nanjing 211189, China.|Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States.
authors.forename: Liang
authors.initials: L
authors.lastname: Ma
authors.affiliation: Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States.
authors.forename: Xiao Cheng
authors.initials: XC
authors.lastname: Zeng
authors.affiliation: Department of Physics, Southeast University , Nanjing 211189, China.
authors.forename: Jinlan
authors.initials: J
authors.lastname: Wang
keywords: ab initio calculation; decoupling and transfer; graphene edge; oxygen intercalation; transition metal catalyst