On the formation of early graphene nuclei on Cu(111) during CVD of graphene using benzene and toluene as C-precursors

The CVD growth of graphene from methane requires temperatures in the range 800-1000°C. The use of liquid aromatic hydrocarbons precursors (e.g. benzene and toluene) may allow reduced temperatures, while preserving high-quality graphene; however, the effectiveness of such precursors in the synthesis of graphene is still debated. Here we investigate through density functional theory (DFT-D3) calculations the molecular-level formation of early graphene nuclei on Cu(111). We estimate the stability of adsorbed benzene and toluene and identify most-likely reaction pathways through the climbing-image nudged-elastic band (CI-NEB) method, leading to the formation of anthracene and biphenyl by recombination reactions of intermediate active species.