Low reactivity of methane on copper surface during graphenesynthesis via CVD process: Ab initio molecular dynamics simulation

tReactivity of methane molecules on the copper surface at the initial stage of graphene growth is investi-gated by the ab initio molecular dynamics simulation. Although most of present graphene-growth modelsadopt the stance that methane molecules are dissociated on the copper surface, methane and fragmentmolecules are not dissociated on the copper (1 1 1) surface in our simulation, which is however reason-able from the thermodynamic viewpoint that the dehydrogenation of methane on the copper surfaceis highly endothermic. Instead, hydrocarbons such as ethane, ethylene and acetylene are formed fromfragment molecules adsorbed on the copper surface.