In this study, high purity graphene nanoflakes (GNF) were synthesized by electric arc discharge technique. The arc discharge method is more advantageous than other graphene synthesis methods for producing cheap and good-quality graphene with minimum defects and not including dangerous chemicals. Because of this advantages, the arc discharge method is one step ahead of all graphene synthesis methods. In order to synthesize GNF, a DC electric arc discharge reactor was designed by our team. Electric arc discharge method based on a principle that provides a constant current between two high purity graphite electrodes to vaporize. After the arc discharge, nanoparticles accumulate on the inner surface of the reactor. The voltage stabilizer DC power source is used to create a current in the environment and the discharge usually occurs in a range 20-60 V. This current can be adjusted depending on the diameter of electrodes, the distance between electrodes and arc current varies between 100 and 150 A. Different characterization techniques such as the Raman spectroscopy, scanning electron microscope and transmission electron microscope were used to characterize the graphene layers synthesized by the arc discharge method. The LD/LG ratio was calculated as 0.66 while the LG/L2D was determined as 1.31. These values show that the purity of the synthesized graphene is compatible to that of commercially supplied graphene. Besides, the synthesized graphene has fewer layer than commercially supplied one. Transmission electron microscope observations confirmed the typical wrinkled feature of graphene.

No abstract

Boron (B) and Nitrogen (N) doped few layer graphene (BNG) is directly synthesized via electric arc discharge (EAD) method. NH 3 and BCl 3 gas mixtures are used in the synthesis atmosphere. Raman spectroscopy is used to determine graphene's purity and number of layers. The investigation of structure and morphology of pristine graphene and BNG are carried out via Transmission Electron Microscopy (TEM). The presence of B and N in the structure of graphene is detected by Energy Dispersive X-ray Spectroscopy (EDS) analysis. Elemental mapping show that N and B are distributed homogeneously in the graphene structure. It is observed that doping process did not affect the positions of the D, G and 2D bands in the Raman spectroscopy. The effect of doping on the number of layers of graphene is found negligible. TEM results exhibit that pristine graphene and BNG have 5 to 6 layers. Besides, the theoretical calculations based on Density Functional Theory (DFT) are employed to support experimental studies. Theoretical results based on DFT showed that bonding of B and N is favorable.

No abstract