Comparative study of nanocarbons synthesized between electrodes in liquid phase by solution plasma.

For several decades, the development of synthesis processes and designs for carbon materials such as graphites, carbon nanotubes, and graphenes has been continuous because of their superior physicochemical properties. The liquid-phase electric discharge process, known as the solution plasma process (SPP), has emerged as a potential synthesis process for carbon materials; however, liquid discharge in organic solutions has not yet been thoroughly investigated. In this study, plasma discharges in benzene (C₆H₆) and pyridine (C₅H₅N) were conducted. During the discharge, two types of nanocarbons with different crystallinities were synthesized simultaneously in different reaction fields: between electrodes and in a liquid phase. The nanocarbons grown between electrodes were collected and then compared with the nanocarbons produced in the liquid phase after discharge. All carbon samples were measured using various techniques such as transmission electron microscopy (TEM), the nitrogen absorption–desorption method, X-ray diffraction (XRD), Raman spectroscopy, CHN elemental analysis, and X-ray photoelectron spectroscopy (XPS). Nanocarbons grown between electrodes in benzene or pyridine were found to be graphite structures, while the nanocarbons produced in the liquid phase were amorphous carbons. On the basis of the results obtained, the formation and growth of the two types of nanocarbon materials synthesized by SPP and their dependence on the position of the reaction field in plasma in the liquid phase are discussed. [ABSTRACT FROM AUTHOR]