Ni nanoparticle has been used to produce GNR by cutting graphene in experiments.However,details of the cutting process are still unknown.In order to understand the cutting mechanism,we have performed molecular dynamics(MD)simulations.In MD trajectories,we found that Ni atoms broke C-C bonds like a plier.Different etching rates of C-C bonds at armchair and zigzagsite resulted in zigzag edge channeling.The etched carbon atoms dissolved into Ni and reacted with H atom decomposed on Ni which supports carbon dissolution mechanism.In additional toMD simulations,DFT calculations were performed to determine energy barriers of C-C bond breaking assisted by Ni atoms.The DFT result is consistent with MD observations.