Development of High Purity, Few-Layer Graphene Synthesis by Electric Arc Discharge Technique

Abstract

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.

The electrochemical properties of reduced graphene oxide film with capsular pores prepared by using oxalic acid as template

“…27,43 The G band and 2D band are found to be sensitive to the number of layers of graphene; according to the ratios of I G /I 2D , all our samples show the multilayer structure. 27 and 170), respectively. This phenomenon signifies that a more conjugated structure in rGO is restored, and that the domain of conjugated structure becomes smaller and more edged carbon atoms appear when the oxygencontaining groups are eliminated and the conjugated structure is repaired during the GO reduction process.…”

“…35,43,44 Furthermore, the weak 2D band has also been observed around at 2920 cm −1 , which is considered as the character of graphene. 27,43 The G band and 2D band are found to be sensitive to the number of layers of graphene; according to the ratios of I G /I 2D , all our samples show the multilayer structure. 27 The intensity ratios of D band to G band (I D / I G ) are found to be about 0.91, 0.93, 0.95, 0.95, 0.94, and 0.96 for GO, rGOF, and C-rGOF12-T (140, 150, 160, and 170), respectively.…”

“…27,43 The G band and 2D band are found to be sensitive to the number of layers of graphene; according to the ratios of I G /I 2D , all our samples show the multilayer structure. 27 The intensity ratios of D band to G band (I D / I G ) are found to be about 0.91, 0.93, 0.95, 0.95, 0.94, and 0.96 for GO, rGOF, and C-rGOF12-T (140, 150, 160, and 170), respectively. Because the ratios of I D /I G have little difference, the area ratios of D band to G band (A D /A G ) are calculated to characterize the samples.…”

“…[16][17][18] Up to date, template method has drawn considerable attention to control the structure of the carbonaceous materials. 24 Although many methods such as chemical vapor deposition, 6,[22][23][24][25] thermal annealing GO, 26 arc discharge method, 27 microwave treatment, 28 and so on have been developed to prepare graphenebased materials, hydrothermal process is commonly believed to be the effective method for preparing various reduced graphene oxide (rGO)-based materials [29][30][31] because this process can be operated under mild conditions and easily scaled up. 21 Furthermore, by using NaCl microcrystal as template in situ, the multifunctional graphene-based materials 22 and the free-standing graphene membranes have been prepared via microwave plasma-enhanced chemical vapor deposition method, and these materials can satisfy the required performances for diverse applications 23 ; the flower-like graphene foam with the hierarchical structure has also been fabricated by using nickel foam template via chemical vapor deposition.…”

“…21 Furthermore, by using NaCl microcrystal as template in situ, the multifunctional graphene-based materials 22 and the free-standing graphene membranes have been prepared via microwave plasma-enhanced chemical vapor deposition method, and these materials can satisfy the required performances for diverse applications 23 ; the flower-like graphene foam with the hierarchical structure has also been fabricated by using nickel foam template via chemical vapor deposition. 24 Although many methods such as chemical vapor deposition, 6,[22][23][24][25] thermal annealing GO, 26 arc discharge method, 27 microwave treatment, 28 and so on have been developed to prepare graphenebased materials, hydrothermal process is commonly believed to be the effective method for preparing various reduced graphene oxide (rGO)-based materials [29][30][31] because this process can be operated under mild conditions and easily scaled up. However, it is still a challenge till now to prepare the rGO films with a special microstructure by using the hydrothermal method.…”