22
2024-03
With the transformation of resource-based cities, Jixi has clearly planned a sustainable development path, from raw mineral extraction to the layout of the graphite new material industry, moving forward steadily and firmly. In 2014, it was awarded the title of "China's Graphite Capital" by the China Mining Association. In this city, one of the four major "coal cities" in Heilongjiang, economic development no longer relies solely on digging deeper; a number of enterprises and projects related to the graphite industry are being established here, and a "China's Graphite Capital" is rising on the black land.
2024-03-22
22
2019-05
Preparation and Application of Porous Graphene
Graphene is a two-dimensional carbon material composed of a single layer of sp2 hybridized carbon atoms arranged in a hexagonal pattern. It has advantages such as a large theoretical specific surface area, high intrinsic carrier mobility, high thermal conductivity, and ultra-high electrical conductivity at room temperature. Due to its unique structure and properties, graphene has gradually become one of the attractive application materials. However, graphene also has its shortcomings. In the field of digital electronics, due to the lack of a bandgap between the electrons in graphene, it is difficult to stop data transmission once it has started. The solution is to create a bandgap by perforating the surface of graphene or integrating two-dimensional graphene to construct a specific three-dimensional structure, forming a porous structure. Preparation Methods for Porous Graphene Template Method The template method can be divided into hard template and soft template methods based on the composition and characteristics of the template. Hard Template Method The preparation of porous graphene materials using the hard template method mainly involves four aspects: (1) preparing the hard template; (2) functionalizing/modifying the template surface to obtain suitable surface properties; (3) coating graphene or its derivatives, such as graphene oxide, onto the template using various methods; (4) selectively removing the template. The hard template method also has many drawbacks, such as relatively low yield, inability to achieve high production, significant limitations when using multi-step synthesis processes, and insufficient structural integrity during template removal. Soft Template Method The soft template method involves a self-assembly reaction between carbon precursors and soft templates, resulting in porous graphene through high-temperature carbonization and polymerization. The pore structure mainly depends on the synthesis conditions, such as the ratio of reactants, type of solvent, and reaction temperature. This method can be directly used to synthesize mesoporous or macroporous graphene materials. Compared to hard templates, soft templates essentially involve synthesis at the molecular level, constructing porous structures while utilizing chemical bonds or hydrophilic/hydrophobic interactions. In the process of preparing porous graphene materials using the soft template method, the chemical reaction between the template and surfactants plays a crucial role. Template-Free Method The template-free method includes etching, solvothermal, and chemical vapor deposition methods. Etching Method The etching method utilizes a chemical reaction between the etchant and graphene, causing the carbon atoms on the surface of graphene to be etched away, leaving behind a pore structure. This method has significant selectivity for material etching, meaning that etching stops immediately after completion, without damaging the remaining material layers. Solvothermal Method The solvothermal method involves using water or organic solvents as the reaction system in a specific high-pressure reaction vessel, heating it to the critical temperature, and synthesizing materials in a high-pressure reaction system. This method greatly reduces environmental pollution, and the porous graphene materials produced have the advantage of controllable pore size. Chemical Vapor Deposition Method The main process of preparing porous graphene materials using the chemical vapor deposition method involves introducing carbon-containing gases such as methane and acetylene, allowing the gaseous carbon source to deposit onto the surface of a solid substrate to produce graphene, and then gradually heating in a protective gas to obtain porous graphene materials. This method is simple to operate, allows for large-scale production, and the resulting porous graphene materials have a complete structure and excellent electrical conductivity. Applications of Porous Graphene and Its Composites Electrode Materials Using porous graphene or composite materials as electrode materials, their highly interconnected structure greatly facilitates the rapid transport of ions, resulting in high capacity and power characteristics. Environmental Adsorption Materials Porous graphene has a rich pore structure, and due to differences in preparation methods, it contains many defects on the surface, making it easier to introduce different functional groups. Porous graphene and its composites have numerous applications in oil/water separation, metal ion adsorption, and dye molecule removal. Separation Field Through model establishment and computer simulation, it has been found that porous graphene has high permeability and selectivity for gas molecules such as hydrogen (H2), nitrogen (N2), and hydrogen sulfide (H2S), effectively separating mixed gases such as H2/CH4, CO2/N2, and H2S/CH4. References: Wu Pengbo, Wang Chengjun, et al. Research Progress on the Preparation of Porous Graphene and Its Nanocomposites Zeng Yang, et al. Research Progress on the Preparation of Porous Graphene Materials Shi Peng, Hou Zhaoxia, et al. Research Progress on Porous Graphene and Its Composites
2019-05-22
18
2022-05
1. As refractory materials: Graphite and its products have high-temperature and high-strength properties, mainly used in the metallurgical industry to manufacture graphite crucibles. In steelmaking, graphite is often used as a protective agent for steel ingots and as the lining of metallurgical furnaces. 2. As conductive materials: In the electrical industry, it is used to manufacture electrodes, brushes, carbon rods, carbon tubes, positive electrodes for mercury rectifiers, graphite gaskets, telephone parts, and coatings for television cathode ray tubes, etc. 3. As wear-resistant lubricating materials: Graphite is commonly used as a lubricant in the mechanical industry. Lubricating oils often cannot be used under high-speed, high-temperature, and high-pressure conditions, while graphite wear-resistant materials can operate without lubricating oil at temperatures ranging from 200 to 2000 °C and at very high sliding speeds. Many devices that transport corrosive media widely use graphite materials to make piston cups, sealing rings, and bearings, which do not require the addition of lubricating oil during operation. Graphite slurry is also a good lubricant in many metal processing operations (drawing, pipe pulling). 4. Graphite has good chemical stability. Specially processed graphite has characteristics such as corrosion resistance, good thermal conductivity, and low permeability, making it widely used in the production of heat exchangers, reaction tanks, condensers, combustion towers, absorption towers, coolers, heaters, filters, and pump equipment. It is widely applied in industries such as petrochemicals, hydrometallurgy, acid-base production, synthetic fibers, and papermaking, saving a large amount of metal materials. 5. As casting, sand casting, pressing, and high-temperature metallurgical materials: Due to the small thermal expansion coefficient of graphite and its ability to withstand rapid cooling and heating changes, it can be used as a casting mold for glassware. Using graphite allows black metals to achieve precise casting dimensions and high surface finish rates, which can be used without processing or with minimal processing, thus saving a large amount of metal. In the production of hard alloys and other powder metallurgy processes, graphite materials are typically used to make molds and porcelain boats for sintering. The crystal growth crucibles for single crystal silicon, regional refining containers, support fixtures, and induction heaters are all made from high-purity graphite. Additionally, graphite can also be used for graphite insulation boards and bases for vacuum smelting, high-temperature resistance furnace tubes, rods, plates, and grid components. 6. Used in the atomic energy industry and national defense industry: Graphite has good neutron moderation properties and is used in atomic reactors. The uranium-graphite reactor is currently one of the most commonly used types of atomic reactors. The moderator materials in power atomic energy reactors should have high melting points, stability, and corrosion resistance, which graphite can fully meet. The purity requirements for graphite used in atomic reactors are very high, with impurity content not exceeding several tens of PPM. In particular, the boron content should be less than 0.5 PPM. In the national defense industry, graphite is also used to manufacture nozzles for solid fuel rockets, missile nose cones, parts for space navigation equipment, insulation materials, and radiation protection materials. 7. Graphite can also prevent boiler scaling. Relevant units have tested that adding a certain amount of graphite powder (about 4-5 grams per ton of water) to water can prevent scaling on the boiler surface. In addition, graphite coatings on bridges and pipelines can prevent corrosion and rust. 8. Graphite can be used for pencil leads, pigments, and polishing agents. After special processing, graphite can be made into various special materials for relevant industrial sectors. 9. Electrodes: How graphite can replace copper as an electrode.
2022-05-18
30
2019-10
This conference is jointly hosted by the People's Government of Xi'an and the Graphene Industrial Skills Innovation Strategic Alliance, with the Xi'an Science and Technology Bureau, the Management Committee of Xi'an High-tech Industrial Development Zone, and the Xi'an Silk Road Graphene Innovation Center as the organizers. Leaders attending the conference include Xu Dingming, former counselor of the State Council and former director of the Energy Bureau; Xing Tao, former deputy director of the Raw Materials Department of the Ministry of Industry and Information Technology; Shi Gaoling, member of the Shaanxi Provincial Science and Technology Work Committee and deputy director of the Science and Technology Department; Wang Huanchang from the Xi'an Political Consultative Conference and Xi'an Federation of Industry and Commerce; Wang Jianhua, executive vice president/secretary-general of the China Industry-University-Research Cooperation Promotion Association; Li Zhijun, secretary of the Party Leadership Group and director of the Xi'an Science and Technology Bureau; and Gu Haiwen, deputy director of the Xi'an High-tech Zone Management Committee. At the opening ceremony, graphene Nobel Prize winner Professor Andre Geim from the University of Manchester, Professor Costas Galiotis from FORTH in Greece, Professor Duan Xiangfeng from the University of California, Los Angeles, Chairman Qu Yan of Changzhou Sixth Element Materials Technology Co., Ltd., Vice President Murni Ali from Nano Malaysia, and Mr. Wang Zhenyu, assistant general manager of China United Property Insurance Company, successively delivered keynote speeches, deeply analyzing cutting-edge graphene technology and exploring the future development of graphene. It is reported that the "International Graphene Product Certification Center (IGCC)" is a global independent third-party certification organization proposed by the European graphene network organization Phantoms Foundation and other related organizations. This certification center was officially established on January 18, 2018, headquartered in Germany, and is currently an independent third-party organization providing voluntary certification services for graphene raw materials and application products in the global graphene industry. The establishment of the IGCC Xi'an Center not only provides strategic support for domestic graphene certification but also greatly stimulates the enthusiasm for the development of the domestic graphene industry. It is also an important measure in response to the Belt and Road Initiative, marking a milestone in the healthy standard development of graphene. This conference features a roundtable meeting on global cooperation in graphene along the Belt and Road, an exhibition of Shaanxi's graphene innovation achievements and the effects of the Belt and Road, a business reception room for enterprises to connect with graphene technology and product needs, a graphene product experience hall that combines popular science and market promotion, a new product launch conference for enterprises to release graphene products globally, and a global graphene industry research report release ceremony, among other special activities. These various activities aim to promote the development of the graphene industry. Among them, this conference has specially established the "Shaanxi Graphene Industrial Innovation Achievements and Belt and Road Effects Exhibition" with the theme of enhancing the central axis of the Belt and Road to boost the future of Shaanxi's graphene industry. The "Effects Exhibition" will showcase the innovative achievements of Shaanxi's innovation teams and research institutions, as well as mature products from Shaanxi's graphene industrialization, demonstrating the new vitality and advantages of Shaanxi's "hard technology" industrial development to the world. Since the Xi'an Silk Road Graphene Innovation Center was established in the high-tech zone, it has implemented the "Five Ones" project for graphene innovation in Xi'an, successively establishing the "Secretariat of the China International Graphene Innovation Conference," forming the "Xi'an Graphene Industrial Development Expert Committee," establishing the "Xi'an Graphene Industrial Alliance," building the "Graphene Industrial Innovation Base," and proposing the "Xi'an Silk Road Graphene Industrial Investment Fund." Focusing on key industry applications, the center has established professional and authoritative industrial service platforms, including research institutes for medical, construction, energy conservation and environmental protection, automotive, military integration, textiles, as well as promotion centers for agricultural and electric heating applications. Through these professional industrial service platforms, the center has effectively promoted the continuous emergence and transformation of Shaanxi's graphene innovation achievements, with a large number of high-end talents and their innovative achievements represented by graphene Nobel Prize winner Professor Andre Geim developing in Xi'an. At the same time, the center has also helped enterprises open up market promotion channels, assisting in the industrial transformation of Xi'an. This conference has specially established 100 "business reception rooms," gathering many domestic and foreign Fortune 500 companies such as Huawei, Haier, Shaanxi Automobile, Oriental Yuhong, and Tata Steel. Focusing on fields such as the Internet of Things, new energy, coatings, thermal management, medical health, aerospace, and energy conservation and environmental protection, it connects over 200 graphene technology innovation needs with global graphene industrialization enterprises, bringing urgently needed graphene-related technologies and products to application enterprises, helping them gain strategic advantages, promote industrial transformation and upgrading, and achieve new industrial growth points. It will also help graphene enterprises expand their product markets, gauge their future development directions, promote the industrialization process of graphene, and open a new era of global graphene industrial development. Everyone participates to build a highland of Silk Road graphene industrial innovation. 2019 is a key year for upgrading the Xi'an hard technology brand. The successful holding of the "2019 China International Graphene Innovation Conference," as an important part of the hard technology conference, helps Xi'an build an innovative ecological chain for the graphene new material industry, promotes international scientific and technological communication and cooperation in Xi'an, and stimulates the innovative vitality of local new material and other hard technology enterprises. At the same time, leveraging the conference platform, it aims to build a technological cooperation channel between Xi'an and the countries along the Belt and Road through graphene new materials, creating a global graphene industrial development community of complementary advantages and win-win cooperation, assisting Xi'an in becoming a city of graphene industrial application innovation along the Belt and Road and a global capital of hard technology, effectively supporting and leading high-quality economic development, and achieving the goal of catching up and surpassing.
2019-10-30
19
2022-10
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