Methane dissociation process in inductively coupled Ar/H2/CH4 plasma for graphene nano-flakes production

Abstract

The role of hydrogen and methane dissociation process in induction plasma synthesis of graphene nano-flakes (GNF) is studied by the optical emission spectroscopy of Ar/H2/CH4 plasma. The condensation of C2 species formed due to methane decomposition produces GNF, which depends on pressure. Electron impact and dehydrogenation processes dissociate methane, which promotes and hinders the GNF production, respectively. The effect of hydrogen is insignificant on quality, size and morphology of the GNF. The CH4 flow rate has no influence on particle temperature but has effect on cooling rate at the point of nucleation and, therefore, on production rate and thickness of GNF.

A review of plasma-assisted catalytic conversion of gaseous carbon dioxide and methane into value-added platform chemicals and fuels

“…In some cases, even pure carbon products can be considered valuable in some forms, e.g. graphene nano-akes 83 and sheets. 84 For a much more in-depth review of this particular process, the reader is referred to an extensive recent review by Scapinello et al 85 The product selectivity of the process depends greatly on the gas temperature of the plasma, many times referred to as the "plasma warmness".…”

Effects of Buffer Gases on Graphene Flakes Synthesis in Thermal Plasma Process at Atmospheric Pressure

“…Nanomaterials 2020, 10 13 of 18 Recent research suggests that the C2 radicals are the main precursor species of graphene flakes [21,25,28]. In the Ar-H2 atmosphere, the formed C2 radicals can be consumed due to the formation of hydrocarbons by collision with the hydrogen molecules through the reaction [73,74]: C2 + H2 → C2H + H, so the synthesis rate of graphene flakes decreases.…”

“…Their research revealed that factors influencing graphene flakes synthesis include the precursor type, reactor design, flow rate of buffer gas, etc. Pristavita et al [23][24][25][26][27][28] and Cheng et al [29] developed a radio-frequency plasma system for graphene flakes synthesis via methane decomposition. Their study indicated that a high reaction temperature and addition of H 2 may promote the transformation of products from spherical particles to graphene flakes.…”

Numerical investigation on the CH4/CO2 nanosecond pulsed dielectric barrier discharge plasma at atmospheric pressure

“…With the emergence and development of advanced processing techniques, CH 4 has received extensive attentions and applications in such fields as nanomaterial synthesis, crop fertilization, and syngas (H 2 +CO) production. [1][2][3] Meanwhile, carbon dioxide (CO 2 ) lies in atmosphere, marsh gas, and oilfield associated gas, playing the significant role in both natural ecological balance and modern society operation by ways of photosynthesis, fuel combustion, and organic decomposition. 4,5 It is well known that CH 4 and CO 2 are undesirable greenhouse gases, so the simultaneous utilization of CH 4 and CO 2 is essential to ensure the energy security of fossil fuels and reduce the greenhouse effect caused by climate changes.…”