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

Reactivity of methane molecules on the copper surface at the initial stage of graphene growth is investigated by the ab initio molecular dynamics simulation. Although most of present graphene-growth models adopt the stance that methane molecules are dissociated on the copper surface, methane and fragment molecules are not dissociated on the copper (1 1 1) surface in our simulation, which is however reasonable from the thermodynamic viewpoint that the dehydrogenation of methane on the copper surface is highly endothermic. Instead, hydrocarbons such as ethane, ethylene and acetylene are formed from fragment molecules adsorbed on the copper surface.