Carbon nanoparticles (CNPs) have been intensively explored due to their wide applications. One of the cost-effective synthesis techniques is arc discharge in liquid, which produces various carbon nanostructures depending on environmental conditions such as catalyst and gases. The use of organic compounds, e.g., toluene, act as a carbon source for carbon nanoparticle growth. However, the carbon structure examinations of the CNPs product deposited in different spots produced by arc discharge in toluene without added catalyst and gases have not been studied in detail. Therefore, the present study investigates the structural characteristics of CNPs produced by arc discharge in pure toluene using Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy equipped by electron dispersive spectroscopy (SEM-EDS) transmission electron microscope (TEM) imaging data. The nanoparticles were collected by scraping powder from four different spots: the electrode handles; the space between the electrodes; in the liquid medium; and at the bottom of the reaction chamber. The C(002) peak analyzed in the diffraction pattern of CNPs collected in these locations shows different intensities and features. The CNPs formed between the electrodes had the most crystalline graphitic structures. The Fourier transform infrared (FTIR) spectra show differences in the C−H absorption, especially for CNPs dissolved in toluene, suggested contains fullerene and its organic hydrocarbon fragments. Moreover, a Raman analysis shows significant differences between the CNPs deposited between the electrodes and those collected from the bottom of the glass chamber, which validates the FTIR, XRD, and TEM imaging data. The powder deposited between the electrodes seems to take the form of CNPs with better graphitic structures; meanwhile, powder collected from the other spots were analyzed to be hydrogenated diamond-like carbon and glassy bulk carbon.
Keywords: arc discharge, carbon, nanoparticles, toluene, structural characteristics