Microwave plasma in liquid n-heptane: A study of plasma-chemical reaction products

Nanosize carbon products formed in microwave discharge in liquid alkanes

“…As we has noted earlier, in the spectra of some products under study one can see wide (of moderate intensity) Raman bands near 2270 and 2000 cm −1 . Presumably (especially in occurrence of Cu) these bands can be assigned to presence of acetylene‐containing carbynoid or butatriene structures in the reaction products .…”

“…Before discussing the results, it is necessary to provide some information about the parameters of the plasma. The emission spectra of MW discharge in liquid alkanes have been analyzed using the experimental setup described earlier . Emission of plasma appears to contain only C 2 Swan bands ( d 3 Π g – a 3 Π u ).…”

“…It has been shown that some amount of graphene‐like solid particles is formed in liquid n ‐heptane soon after the MW discharge initiation . Insignificant amounts (<1%) of polycyclic aromatic hydrocarbons are detected in liquid hydrocarbon after centrifugation and isolation of dispersed phase which can be precursors of graphene‐like carbon nanoparticles (color of liquid changes from transparent in initial n ‐heptane to reddish).…”

“…The spectra were interpreted by referencing to data available in literature . Earlier, we have compared the Raman spectrum of the solid product obtainable by in‐liquid MW plasma processing of n ‐heptane with the spectra of reduced graphite oxide and of exfoliated crystalline graphite (all recorded on the same instrument under the same conditions) . The comparison has revealed that the spectrum of the product obtained from n ‐heptane contains all Raman bands necessary to categorize this material as a “damaged graphene” and, mostly, not a single‐layer one.…”

“…Experimental setup is presented in Figure and has been described in details elsewhere . MW energy from a magnetron (2.45 GHz, 500 W) was fed by a rectangular waveguide into a metal chamber.…”