Comparison study on carbon nanomaterial synthesis from methane and acetylene in DC arc plasma

The carbon nanomaterials are obtained from methane and acetylene pyrolysis by thermal plasma jet at the temperature up to 2500 K. The morphologies and nanostructures of carbon nanomaterial are investigated by various bulk characterization techniques and a detailed chemical kinetic simulation. The high reaction temperature can promote the transformation of methane pyrolysis products from amorphous spherical carbon to graphene nanoflakes (GNFs), but acetylene to onion-like particles. The feedstock species and reaction temperature affect first aromatic molecules formation and thus change condensed carbon inception rate. The carbon source used for carbon nuclei formation paths has a competitive relationship with surface reactions. Results suggest that the governing factors on the carbon black morphologies are determined by the nucleation, surface growth and particle-particle collision efficiency, which are affected by reactants and reaction temperature. Its nanostructures refer to a result of the equilibrium configuration of PAH clusters under different temperatures. Particularly, the high hydrogen/carbon ratio may prefer GNF formation.