Characterization of carbon products from microwave-driven methane pyrolysis

Hydrogen production via methane pyrolysis is projected to have a key role in achieving net zero GHG emission by 2050. Carbon makes up to 75% by mass of the products of methane pyrolysis, indicating the importance of a thorough characterization to find its potential applications. A new approach is methane pyrolysis utilizing microwaves, where the carbon product serves as receptors for the microwave energy. In this method, methane decomposes and forms solid carbon. In this study, we evaluated the morphological and structural features of the produced carbon using SEM, XRD, XPS, Raman spectroscopy, and thermogravimetric analysis. The analysis indicates that the pyrolytic carbon produced through this process is highly pure and exhibits a semi-graphitic structure with localized defects. Additionally, the surface morphology of the carbon material was observed to possess a rough cauliflower-like texture. A thorough characterization of carbon revealed several potential applications, including the utilization of granular carbon in electric arc furnace for steelmaking, the feedstock for graphene production, and serving as an anode material in Na-ion batteries with further optimization of the production process. Safe sequestration of the carbon due to limited demand is feasible as the carbon is pure and oxygen-free, indicating its potential to remain unreacted over a long period after sequestration.