Synthesis of Carbon Nanoparticles from Methane Using a Non-Thermal Plasma

Our study proposes a novel solution for two concurrent environmental challenges: methane flaring during oil and gas extraction, and the increasing need for carbon nanoparticles in Lithium-ion batteries. Non-thermal plasma is employed to convert waste methane into valuable battery material, incentivizing carbon footprint reduction and creating additional income streams. Previous research by Woodard et al. (Plasma Chemistry Plasma Processing 2018) emphasized the efficacy of acetylene for the nucleation of small carbon nanoparticles. Conversely, methane exhibits limited nucleation abilities but rapid film growth on the reactor walls. To address these constraints, we devised a non-thermal plasma system comprising two consecutive reactors. The first plasma reactor nucleates seed carbon nanoparticles from acetylene onto which more carbon from methane is grown in-flight within the second reactor. Optimization of the various experimental variables led to a yield ~220 mg/hr of nanoparticles with a methane consumption rate of ~78%. Raman spectroscopy showed improved graphitization with increased RF power and methane flow rate, suggesting that the addition of the C:H bond in methane enhances graphitization. Carbon NP produced in this study showed similar capacity and Coulombic efficiency to commercially manufactured carbon black when tested in Li-ion batteries. Preliminary results will be presented on the use of metalorganic precursors in place of acetylene for the nucleation of seed particles.