Layer-by-layer synthesis of bilayer and multilayer graphene on Cu foil utilizing the catalytic activity of cobalt nano-powders

Layer-by-layer synthesis of graphene films has been of considerable interest for the precise layer engineering. However, the additional graphene layer typically forms on the Cu surface but underneath the existing graphene layer, limited by the catalytic substrate mediated growth mechanism. This work introduces a reliable cobalt (Co) nano-powders (NP) assisted technique to synthesis the bilayer graphene (BLG) and multilayer graphene (MLG) layer-by-layer on Cu foil in one-step. With nanostructure and high-surface-area, the Co NP demonstrates much higher catalytic activity to provide long-lasting catalytic activity during the graphene growth. The growth of the BLG activated by the Co NP solely has been observed with the growth rate exceeding the Cu-catalyzed single layer graphene (SLG), which validates the superiority of the homo-epitaxial growth. Fully covered uniform Bernal-stacked BLG and high coverage tri-layer graphene are successfully achieved on Cu foils through the optimal growth conditions. This work creates a pathway toward effective production of BLG/MLG via layer-by-layer mode. The utilizing of the NP catalyst may serve as a more general technique for the one-step synthesis of other hybrid heterostucture.