Synthesis, diagnostics and application of carbon nanostructures in arc discharge Open Access
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Carbon nanostructures such as single-walled carbon nanotubes (SWCNT) and graphene attract a deluge of interest of scholars nowadays due to their very promising mechanical, electrical, and thermal properties. Anodic arc discharge is one of the most practical and efficient methods, which can provide a high influx of carbon materials to the developing structures at relatively higher temperature. Therefore, the productions in arc have few structural defects and better crystallinity.In this work, magnetic fields were utilized to control the arc synthesis according to the strong magnetic responses of arc plasma. The magnetic field can narrow diameter distribution of catalyst nanoparticles and therefore control diameters of bundle and individual SWCNT. A creative approach for synthesizing high-purity SWCNT and graphene in one step was proposed. It was also demonstrated that few-layer graphene with large yield and high quality was synthesized under pressure of 1600 Torr in air environment. Scanning electron microscope, transmission electron microscope and Raman spectroscopy were employed to analyze carbon nanostructures. To understand the synthesis process of carbon nanostructures in details, two diagnostics facilities were applied for plasma parameter measurements: Langmuir probe and ultraviolet-visible spectrometer. Finally, in order to extend the research of carbon nanostructures to application, paper-based ultracapacitors were fabricated by rod-rolling method using the suspension ink of carbon nanostructures synthesized in various magnetic conditions. It was shown that the thin film of composite of SWCNT and graphene synthesized with magnetic field had better conductivity than that of pure SWCNT synthesized without magnetic field. In addition, the specific capacitance of composite-based ultracapacitor is much higher than that of SWCNT-based ultracapacitor.