Ab Initio Molecular Dynamics of the Initial Growth of Few-Layer Graphene on a Cu–Ni(111) Catalyst

Abstract

A Cu−Ni catalyst is commonly used to grow fewlayer graphene (FLG) with a controlled number of layers by using chemical vapor deposition. However, the mechanism of FLG growth on the Cu−Ni catalyst is still poorly understood. Here, the segregation of C adatoms in the Cu−Ni(111) catalyst is systematically explored using ab initio molecular dynamics. In the Cu−Ni(111) catalyst, the dynamics of C adatoms are controlled by the Ni atoms because Ni−C bonds have a higher stability than Cu−C bonds. By forming oriented channels, the Ni atoms facilitate the segregation of C adatoms into the interface between the graphene top layer (GTL) and the Cu−Ni(111) catalyst. Moreover, diffusion out of the bulk of C adatoms can be activated at a lower energy than diffusion into the bulk. We also find that the C dimer at the interface has a lower adsorption energy than that at the subsurface and vice versa for the C monomer. Therefore, the C adatom must bond with another C adatom when it arrives at the interface region and bonds with GTL, indicating the early stages of add-layer graphene nucleation. This study reveals the crucial mechanism for FLG growth and confirms the segregation growth mechanism on the Cu−Ni(111) catalysts.