Continuous preparation and formation mechanism of few-layer graphene by gliding arc plasma

Environmental-friendly, rapid, and continuous preparation process of few-layer graphene has been developed by alternative-current (AC) rotating gliding arc plasma, which contains the characteristics of equilibrium plasma and non-equilibrium plasma. In the process, methane was directly cracked in the plasma and then graphene sheets were generated. The effects of hydrogen and gas flow rate on the yield, size, morphology and structure of graphene have been investigated. In addition, the formation mechanism of graphene was also revealed by using the reactive molecular dynamic method. The simulation results showed that the growth process of graphene clusters by methane radicals includes three stages: elongation of the carbon chains, cyclization of the carbon chains, and condensation and sheeting of clusters. The carbon source concentration influences the graphene clusters. Increasing the carbon source concentration was found to enlarge the size of graphene clusters but are more prone to curling and closing. The formation of C-H bonds can reduce the peripheral dangling bonds of the clusters, thereby delaying the closure of the clusters. It laid a foundation for understanding the growth mechanism of graphene.