Combustion synthesis of graphene materials

Combustion synthesis (CS) of graphene by a novel type of exothermic self-sustain reaction between a refractory ceramic compound (silicon carbide) and polymer (polytetrafluoroethylene, PTFE) under the inert gas (argon) environment is reported. The synthesis of graphene is confirmed by both transmission electron microscopy and Raman spectroscopy. It is important that the produced graphene has low (<1 wt.%) oxygen content. The mechanism for CS of graphene is also discussed. It is experimentally shown that fluorocarbon gases (e.g. tetrafluoroethylene, C2F4) released due to PTFE decomposition in the combustion wave, reduces SiC to tetrafluorosilane (SiF4) gas and meso-porous carbon particles with folded “native” graphene layers on their surfaces. The continuous supply of carbon, in the form of fluorocarbon gases, and the high reaction temperature (∼1400 K) enables further rapid growth of “free-standing” graphene sheets on the surface of those graphene-coated particles. The developed method for synthesis of graphene does not require an external energy source, since it occurs in a self-sustained synergetic manner. This approach is also flexible in terms of tuning the synthesis conditions, and allows easy scale-up.