Xia Weidong, a professor from the Department of Thermal Science and Energy Engineering at the School of Engineering Science, University of Science and Technology of China, and Hefei Carbon Art Technology Co., Ltd. have proposed a new method of "synthesizing large-area uniform thermal plasma using magnetic dispersion arcs to synthesize graphene". The technical bottleneck of plasma technology or high energy consumption, or low product uniformity and insufficient production stability is expected to achieve large-scale continuous production. The research results were recently published on Carbon under the headings Continuous synthesis of graphene nano-flakes by magnetically rotating arc at atmospheric pressure and The morphological transformation of carbon materials from nanospheres to graphene nanoflakes by thermal plasmas. Graphene (Graphene) has excellent optical, electrical, and mechanical properties, and is considered to be a revolutionary functional / structural material in the future. It has important applications in energy, environment, biomedical, electronic devices, chemical industry, and aerospace. . The use of radio frequency induction heating and microwave heating plasma to prepare graphene has high energy consumption and is difficult to industrialize. Thermal plasma pyrolysis of hydrocarbons to synthesize graphene. Because plasma conductivity rises rapidly with increasing temperature, the arc automatically shrinks to a very small range. The millisecond reaction time required for the synthesis of graphene is difficult to achieve uniform heating. The product has poor uniformity and high energy consumption. Using the technology of magnetic dispersion arc developed by the research group to generate a large area of ​​uniform plasma, the problem of rapid and uniform heating of materials by plasma is solved. The prepared graphene has a plane size of 50-300nm and 2-5 layers, showing good crystal structure and large specific surface area, and good product uniformity; the preparation method and equipment are simple, one-step synthesis, no reduction and no substrate , Catalyst, solution or acid, the yield is about (~ 14%), the energy consumption is about ~ 0.4kW · h / g, the cost is low, and it has the prospect of achieving low-cost large-scale continuous production. The research work explored the relationship between plasma parameters, raw gas composition and nanographene morphology, layers and defects, and also revealed the process conditions required to produce high-purity graphene. Combining the numerical simulation of the flow field temperature field of the plasma reactor and the calculation of chemical reaction kinetics, the possible formation mechanism of graphene is proposed: the nucleation precursor with low collision frequency is conducive to the formation of a sheet-like core and is rich in Planar growth is maintained in a hydrogen and high temperature plasma environment. The clarification of the formation mechanism of graphene provides theoretical guidance for product production control. The team's specially appointed associate researcher Wang Cheng and doctoral student Chen Xianhui are the first authors of the two papers respectively, Xia Weidong is the corresponding author of the two papers, and Wang Cheng and associate professor Ye Taohong are the co-corresponding authors of the two papers. The project was supported by the National Natural Science Foundation of China, the Special Instrument Fund of the Chinese Academy of Sciences and Hefei Carbon Art Technology Co., Ltd. Baking Paper Use Aluminium Foil,Aluminium Foil Jumbo Roll,Takeaway Food Package Wrapper Aluminium Foil,Aluminium Lidding Foils For Water Cups Henan Everwin Trade Co., Ltd. , https://www.ewaluminium.com
Figure: Arc CCD images of different modes and graphene sample detection results