Methane/nitrogen plasma-assisted synthesis of graphene and carbon nanotubes

Abstract

An experimental and numerical study of plasma-assisted synthesis of graphene and carbon nanotubes is presented. Experiments were carried out using methane/nitrogen plasma generated by a DC plasma torch with pressure variation in the 100–710 Torr range. The synthesis products were studied by synchronous thermal analysis and scanning electron microscopy. The results of these experiments are shown in thermogravimetry graphs and snapshots of the synthesized structure morphology. It is shown that structures in the form of graphene ‘flakes’ are thermally stable. Carbon nanotubes synthesized at different pressures show different morphologies. Using express gravimetric analysis, the maximum nitrogen content in nanostructures was determined to be 8 at.%. Spectral investigation of a jet of nitrogen plasma with the addition of methane and pure nitrogen under atmospheric pressure was performed. The results of the emission spectra analysis agree with the gas phase composition obtained by kinetic modelling. It is shown that the conversion products consist of the following components: H, H2, C2, CN, HCN, C2H2, C4H4, and C6H6, the ratio of which varies with decreasing temperature. Our calculations show that the gas phase composition remains practically unchanged at different pressures.

Advance in Using Plasma Technology for Modification or Fabrication of Carbon‐Based Materials and Their Applications in Environmental, Material, and Energy Fields

“…Shavelkina et al. [ 124 ] directly fabricated graphene and CNTs doped with nitrogen using a CH 4 ‐N 2 direct current (DC) plasma at pressures of 100–700 Torr. The N content of the CNTs reached up to 8 at%, and the formed graphene flakes displayed high thermal stability.…”

Effect of helium/propane–butane atmosphere on the synthesis of graphene in plasma jet system

“…Thus, it has been experimentally shown that using the DC plasma torch to generate the helium/propane-butane plasma jet, a highly efficient system for the graphene To analyse kinetic processes initiated in the arc plasma torch in the helium/propane-butane mixture, an approach was used similar to that described and applied in our work [18]. To determine the mixture composition in different temperature ranges in the gap between the reactor nozzle and the material collection point, we used our RADICAL software package [28][29][30] and the extended scheme of chemical reactions involving 769 reactions between 123 components.…”

“…Previously, we have shown a possibility of the graphene synthesis using the DC plasma torch, at pressures of 100-710 Torr [18][19][20]. Varying the plasma-forming gases and the carbon sources (solid, liquid, and gaseous carboncontaining substances), the jet cooling process, and the product collecting system, graphene, hydrogen and nitrogen modified graphene, as well as carbon nanotubes were synthesised in the same reactor.…”

1D modeling of the equilibrium plasma flow in the scope of direct current plasma torch assisted graphene synthesis

“…Raman spectrum of graphane has specific peaks D, G and 2D at 1349, 1586 and 2695 nm with altered relation I D /I G (figure 5). According to [22][23][24] the relative intensity of the G-peak with respect to the 2D-peak (I G /I 2D ) along with the shape of the 2D-peak is also an indication of the number of graphene layers. The peculiarity of hydrogenated graphene synthesized by means of DC plasma torch in comparison with that in [4] is its origin in the volume of plasma jet, not as a result of the treatment of the pristine graphene with hydrogen containing medium.…”