nbsp; nbsp; Nanographite and edge carbon effect
π electrons, electronic valence states and surface functional groups on nano graphite dominate the function of carbon adsorbent as the elements controlling the neutron characteristics of electricity in CTI test. The following figure shows the basic concept of nano graphite [29,30]. It can be seen from this that the number of carbon atoms at the edge of nano graphite is roughly the same as that of the bulk carbon atoms. Almost all the carbon atoms of aromatic molecules are located at the end, while the number of carbon atoms at the edge of the infinite graphite layer is almost negligible. There are two forms of edge carbon: armchair and zig zag edge. The electronic state of the edge carbon in nano graphite depends on the shape and size of its edge, and is different from that in aromatic molecules and large graphite flakes, which may lead to the discovery of some novel physical properties. At the same time, it can be seen that the basic composition of nano graphite microcrystals of microporous carbon makes most carbon atoms located on the surface, so microporous carbon is also called surface solid. Br
the theoretical calculation of pore model currently adopted generally ignores the following factors : (1) various defects of microcrystalline carbon sheets; (2) The edge carbon effect caused by the finite size of microcrystalline graphite; (3) The effects of heterogenic donor and polar functional groups on adsorption. However, in fact, the adsorption process is a macro effect under the joint action of the above factors and pores, so it is particularly necessary to discuss the edge effect of carbon adsorbents. Due to the non-polar nature of carbonaceous adsorbents, the interaction between adsorbate molecules, adsorbents and adsorbate molecules in the adsorption process is dominated by the dispersion force in the vanderwaals force as described above. However, due to the unsaturation of edge carbon and the existence of unpaired electrons, the adsorption behavior, especially the adsorption of polar molecules or polarizable molecules, will be affected [14, 32]. The existence of marginal carbon is often used as the active site of chemisorption (e.g. chemisorption of o_2), and_ The chemical activity of 2 is also very strong. Even at a very low temperature (such as -13 ℃) , O will occur on the clean carbon surface_ 2, so the edge carbon atoms often combine with O atoms to form oxygen-containing surface functional groups, which ultimately affect the macro adsorption behavior in this form. Br
company profile Technical support, training and after-sales service are recognized as high-tech enterprises by Beijing Zhongguancun Science Park. Br
the full-automatic nitrogen adsorption specific surface area tester developed and produced by our company is widely used in graphite, battery, rare earth, and researchers predict that such new materials will be put on the market within two years in the research, development, production, analysis, and monitoring of ceramic, alumina, chemical and other industries and University powder materials. After years of efforts, our company has a large number of customers. The advanced technology, stable performance and good after-sales service of instruments make our products enjoy a high reputation and trust among customers. Br
3h-2000iii specific surface instrument is a famous brand in China. It has a large number of customers (see the company's station for details). It is the latest model with high test accuracy and good repeatability. It is the only model in China with a repeatability of 1.5%. 3h-2000 series specific surface tester is the most widely used model in China. It is widely used for testing battery graphite, rubber carbon black, University, catalyst and other powder materials, including br
1, the performance characteristics of 3h-2000 Ⅲ specific surface area tester issued by mints, customs, Chinese Academy of Sciences and other units, br
1, high measurement accuracy, good reproducibility, and the relative error of repeatability is less than ± 1.5% (the only one in China); Br
2. The measurement range is wide, and the specific surface area can be measured within 0 × Materials within the range of 103m2/g meet the measurement of specific surface area of all powder materials and porous materials; Br
3. The test speed is fast. Each sample is about 5 minutes on average, which is only one fourth of the test time of similar foreign instruments; Br
4. The low-temperature nitrogen adsorption dynamic chromatography is adopted, and the unique parallel gas circuit at home and abroad eliminates the external influences such as ambient temperature, humidity and atmospheric pressure. There is no need to vacuum, and the requirements for laboratory conditions are relatively loose; Br
5. The instrument integrated degassing device (non split type, exclusive in China) solves the problem of degassing and testing integration internationally, and realizes the in-situ treatment of samples. It only needs one installation and zero contact with air, ensuring the high efficiency and effectiveness of sample pretreatment; Br
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7. The software is a self-developed high-precision data processing system, 16 bit data acquisition card, with a minimum resolution of ＜ 0.01mv, fully automatic trigger, ensuring high measurement accuracy and sensitivity, stable operation, compatible with Win98, winme, WIN2000, WINXP and other operating systems, USB interface; Br
8. The instrument software has superior operation stability and reliability, excellent performance, and the hardware adopts stable and durable key components, which is suitable for frequent testing; Br
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3h-2000 series instrument is hpdai-88 high-efficiency dynamic adsorption instrument, which is gb/t (original gb/t) according to the national standard. This model passed the appraisal of the science and Technology Bureau of the Ministry of chemical industry on August 5, 1988, and the technical appraisal certificate number is:  Huake appraisal No. 48. Br
after improvement and upgrading, the 3h-2000 series instruments passed the metrological test of the National Research Center for certified reference materials on December 16, 2002. The certificate number is JJZ No. 2002- (17) -017. Br
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