Crystalline Ni3C as both carbon source and catalyst for graphene nucleation: A QM/MD study

Abstract

Graphene nucleation from crystalline Ni 3 C has been investigated using quantum chemical molecular dynamics (QM/MD) simulations based on the self-consistent-charge density-functional tight-binding (SCC-DFTB) method. It was observed that the lattice of Ni 3 C was quickly relaxed upon thermal annealing at high temperature, resulting in an amorphous Ni 3 C catalyst structure. With the aid of the mobile nickel atoms, inner layer carbon atoms precipitated rapidly out of the surface and then formed polyyne chains and Y-junctions. The frequent sinusoidal-like vibration of the branched carbon configurations led to the formation of nascent graphene precursors. In light of the rapid decomposition of the crystalline Ni 3 C, it is proposed that the crystalline Ni 3 C is unlikely to be a reaction intermediate in the CVD-growth of graphene at high temperatures. However, results present here indicate that Ni 3 C films can be employed as precursors in the synthesis of graphene with exciting possibility.