新型炭材料

XU Bing-she, ZHANG Chun-yi, YANG Yong-zhen, LIU Xu-guang, LUO Qiu-ping

2007, 22(03): 193-198.

Abstract(2480)

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Abstract:
Deoiled asphalt was chosen as the carbon source and FeCl3 as the catalyst, to prepare vapor-grown carbon fibers (VGCFs) with different morphologies, by chemical vapor deposition, in an atmosphere of argon and hydrogen. The influence of reaction time (10, 20, 25, 30, and 40min) on the morphologies and structures of products at 1100℃ was discussed. The morphologies and structures of the products were characterized by field-emission scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction and Raman spectroscopy. Results showed that the VGCFs became relatively straight and then interpenetrating. The diameters of the VGCFs were 1.0 to 1.2μm, 250 to 300nm, 350 to 400nm, and 700 to 800nm when the reaction time was 10, 20, 25, 30, and 40min, respectively. In addition, V-shaped VGCFs were observed.

由柏木制备纳米孔结构炭材料I.制备与孔结构(英文)

Eiki Ito, Ikuyoshi Kouchi, Sylwia Mozia, Masaharu Okuda, Takashi Nakano, Masahiro Toyoda, Michio Inagaki

2007, 22(03): 199-205.

Abstract(2205)

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Abstract:
Nanoporous carbons were prepared from cypress chips under a flow of superheated steam, and their surface area reached more than 1000m2/g without an additional activation process. Cypress charcoals prepared at a temperature of 800－870℃ had a large external surface area of more than 400m2/g, comparable to the microporous surface area, even though only 30－40m2/g was obtained by carbonization in a flow of Ar gas. Cypress charcoals prepared above 900℃ were microporous with a microporous surface area more than 800m2/g and an external surface area of about 150m2/g. The pore structure in cypress charcoals could be controlled by selecting the temperature of the steam.

纳米碳管/氧化锌异质结构的合成及发光性质

QIU Jie-shan, SUN Tian-jun

2007, 22(03): 206-212.

Abstract(2326)

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Abstract:
Carbon nanotubes (CNTs) have been regarded as one of the ideal substrates for making functional nano- and microstructures. In the present study, CNT/ZnO heterostructures were synthesized successfully by a catalytic carbothermal reduction process with CNTs as substrate and Cu as catalyst. The structure and the morphologies of as-prepared materials were characterized by scanning electron microscopy, X-ray diffraction and transmission electron microscopy. It is found that the growth of ZnO nanowires on CNTs follows the Vapour-Liquid-Solid (VLS) mechanism. ZnO nanowires in the heterostructures have a perfect crystalline structure, while the crystalline structures of the CNTs remain unchanged. Distinctive interfaces between the ZnO nanowires and the CNTs, as well as between the ZnO nanowires and the Cu catalysts can be clearly observed. The CNTs with larger diameters favor the growth of ZnO nanowires in high density. The shapes of ZnO materials on the CNT substrate change from nanowires, to nanoparticles, and finally to nanorods as the deposition temperature increases. The photoluminescence properties of CNT/ZnO heterostructures are different from those of ZnO nanowires and CNTs that are present separately, and exhibit higher intensity in the blue band than in the ultraviolet band at room temperature.

碳纳米管负载Fe2O3催化剂的制备及其乙苯脱氢催化活性(英文)

PENG Feng, FU Xiao-bo, YU Hao, WANG Hong-juan

2007, 22(03): 213-217.

Abstract(2441)

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Abstract:
Carbon nanotubes were modified by FeSO4-H2O2 and iron hydroxides were adsorbed on the walls of carbon nanotubes simultaneously. These precursors were treated at 723K for 2h under hydrogen, nitrogen and air atmosphere to prepare carbon nanotube-supported γ-Fe2O3 catalyst, a γ-Fe2O3 and α-Fe2O3 compound catalyst and amorphous Fe2O3 catalyst, respectively. The catalysts were characterized by X-ray diffraction, transmission electron microscopy and TG-DSC. The catalytic activity was estimated by the dehydrogenation of ethylbenzene to styrene in a fixed bed reactor with a continuous flow system at atmospheric pressure. Results show that the effect of thermal treatment conditions on the catalytic performance activity for the dehydrogenation of ethylbenzene is very sensitive. Novel carbon nanotube-supported crystalline Fe2O3 catalysts were found to have a high activity and selectivity for ethylbenzene dehydrogenation.

水溶液中分散的多壁碳纳米管与血液蛋白质分子的作用研究

MENG Jie, YANG Man, WANG Chao-ying, KONG Hua, WANG Rui, WANG Chen, XIE Si-shen, XU Hai-yan

2007, 22(03): 218-225.

Abstract(2181)

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Abstract:
Stable dispersions of carbon nanotubes in aqueous solution and their interactions with proteins play a crucial role in the realization of biomedical applications of carbon nanotubes. In this work, multiwalled carbon nanotubes (MWCNTs) were oxidized by a concentrated H2SO4 and HNO3 mixture with the aid of ultrasonication to obtain a surfactant free stable aqueous solution with concentration of MWCNTs of 0.23mg/mL. High and ultra highspeed centrifugation were applied to the aqueous solution to yield MWCNTs in deposits and in supernatants, which were characterized by scanning electron microscopy, dynamic light scattering, UV/VIS/NIR spectrophotometry, and X-ray photoelectron spectroscopy. Results showed that oxygencontaining groups including carboxyl acid group were introduced into the MWCNTs and their length were shortened from ~50μm to 500-800nm. The MWCNTs in the supernatants subjected to different centrifugal rates had the same average length and a similar length distribution pattern. The MWCNT aqueous solutions displayed specific adsorption at 253nm, which was used to determine the amount of MWCNTs dispersed in water by a spectral analysis. The nonspecific adsorption between MWCNTs and single albumin, single fibrinogen, and the dual proteins was investigated using sodium dodecyl sulphate-polyacrylamide gel electrphoresis, and spectrofluorometry. It was demonstrated that MWCNTs preferred to adsorb fibrinogen of albumin. Modification of MWCNTs by polyethylene glycol (PEG)-750 suppressed the fibrinogen adsorption.

化学沉积法制备氧化锰/多孔炭复合材料及其电化学性能

LI Qiang, LI Kai-xi, FAN Hui, GU Jian-yu, SUN Guo-hua

2007, 22(03): 227-234.

Abstract(2176)

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Abstract:
Manganese oxide/porous carbon composites were prepared by chemical deposition. The effects of the amount of manganese oxide loading and heat treatment temperature on the physical and electrochemical properties of the composites were investigated by SEM, XRD and charge/discharge testing. It was found that manganese oxide was uniformly loaded into porous carbon at low temperatures and pore structures were also modified by the reaction of carbon atoms with the manganese oxide. However the loading uniformity of manganese oxide was destroyed when the heat treatment temperature was above 400℃. Manganese oxides were amorphous when the composite materials were dried at 110℃ and 400℃, but turned into γ-Mn2O3 at 800℃. The single-electrode specific capacitance of composites loaded with mass fraction 1.7% manganese oxide and dried at 110℃ in air reached 340F/g, which is 34% higher than that for a pure porous carbon electrode.

纳米硅/炭复合材料的制备及其电化学性能

CHEN Xiao-hong, SONG Huai-he, YANG Shu-bin

2007, 22(03): 235-241.

Abstract(2313)

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Abstract:
A nano-Si/C composite as the anode material for a lithium-ion secondary battery was prepared by polymerization and condensation of petroleum heavy oil with dispersed nano-Si powders at 460℃ and carbonization at 900℃. The influences of adding nano-Si powders to heavy oil on yield, microstructures and electrochemical properties were investigated. Results showed that the addition of nano-Si powders is beneficial for increasing the yield of solid products. Nano-Si powders were uniformly embedded in the carbon matrix and the crystallinity of nano-Si powders had no change before and after polymerization. The nano-Si/C composite had a first reversible capacity of 498mAh/g and a cycle efficiency of 90%.

爆轰裂解可膨胀石墨制备石墨微粉(英文)

SUN Gui-lei, LI Xiao-jie, YAN Hong-hao

2007, 22(03): 242-246.

Abstract(2608)

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Abstract:
A method to produce graphite micro-powder by detonation was provided and the detonated powder was characterized by XRD, SEM and nitrogen adsorption. Results indicated that the particle size of the detonated expandable graphite powder were in the range of 1 to 10μm, the BET specific surface area increased from 8.096 to 47.48m2/g, while the crystal parameters and flake-like morphologies changed little. Detonation offered a more convenient, quick and energy-saving method to make micrometer-sized graphite powder.

炭/炭复合材料新型热梯度制备工艺(英文)

Shameel Farhan, LI Ke-zhi, GUO Ling-jun

2007, 22(03): 247-252.

Abstract(2320)

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Abstract:
Solid cylindrical carbon-carbon composites were processed using conventional thermal gradient chemical vapor infiltration. High thermal conductivity (55W/m•℃) carbon fibers (48k) were inserted in the center of a cylindrical low thermal conductivity (0.15W/m•℃) needle punched carbon felt preform, to create a thermal gradient because of the difference in thermal conductivities. The hottest portion (900－1200℃) was along the inserted carbon fibers, where the pyrolytic reaction of natural gas occurred. The densification radially moved outwards and ultimately a density of 1.778g/cm3 was obtained after 67h. The process parameters such as the electric power of the furnace, electrical resistance of the sample, densification time, and the position of the deposition layer were studied. A densified sample having a volume fraction of carbon fibers of 10% was tested for ablation and erosion. The microstructure of the pyrolytic carbon matrix of the as-prepared sample was investigated by polarized light microscopy and scanning electron microscopy.

负载铂纳米粒子大孔炭材料的无模板制备

LIU Shu-xia, HE Jun-hui

2007, 22(03): 253-258.

Abstract(2538)

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Abstract:
Abstract: The preparation of macroporous carbon materials containing Pt nanoparticles was investigated. Starch and H2PtCl6 were used as the carbon and Pt source respectively. Two impregnation methods were used to incorporate Pt into the starch gel based macroporous carbon. In the first (A) the starch gel monolith was soaked in H2PtCl6 and reduced by NaBH4. In the second (B) H2PtCl6 was added to the precursors before the starch gel monolith formation. It was found that the size and wall thickness of the macropores of the samples could be controlled by adjusting the starch content, and the carbon yield was increased from 24% to 37% for method A and to 44% for method B. The volume expansion during the carbonization was also suppressed. A smaller particle size and narrow size distribution (average particle diameter is 3.5nm, average particle diameter deviation is 0.9nm) were obtained by method B, compared to method A (average particle diameter is 5.5nm, average particle diameter deviation is 1.8nm).

印刻法制备中间相沥青基中孔炭(英文)

LIU Ying, ZHAN Liang, ZHANG Rui, QIAO Wen-ming, LIANG Xiao-yi, LING Li-cheng

2007, 22(03): 259-263.

Abstract(2156)

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Mesoporous carbons (MCs) were prepared by an imprinting method, using mesophase pitch and nanometer colloidal silica solution as carbon precursors and pore generators, respectively. The effects of the type of mesophase pitch, the imprinting temperature, and the silica content on the porous properties of MCs were investigated. It was found that the pore size distributions of MCs were similar irrespective of the imprinting temperature and the amount of silica used because of the imprinting mechanism. The mesopore volume of MCs increased with an increasing amount of silica. There existed an optimum imprinting temperature slightly higher than the softening point of the mesophase pitch used. Easy imprinting was found for naphthalene based mesophase pitch with a low softening point and fine average particle size as compared with a coal based mesophase pitch. Mesoporous carbons were provided with a specific surface area and a total pore volume of 482m2/g and 1.62cm3/g, respectively.

超临界水活化褐煤制取活性炭

CHENG Le-ming, JIANG Wei, ZHANG Rong, BI Ji-cheng

2007, 22(03): 264-270.

Abstract(2097)

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Abstract:
Conversion of Xiaolongtan lignite to activated carbon was conducted in a semicontinuous supercritical water (SCW) reactor. The effects of temperature (600-700℃), pressure (0.1-30MPa) and KOH loading (mass fraction 0%-15%) were investigated. The coal conversion, iodine number and BET surface area of the activated carbon increase with temperature, and the meso-pore formation is also enhanced at relatively higher temperatures. Compared with steam activation at ambient pressure at the same temperature, SCW activation yields activated carbon with an excellent adsorption and develops mesopores. When the activation pressure increase from 0.1MPa to 25MPa at 650℃, the BET surface area and meso-pore ratio increase by 74% and 38%, respectively. The activated carbon has a BET surface area of 825m2/g with the addition of mass fraction 10% KOH in lignite as catalyst. Moreover, the ash content of the activated carbon is lower than mass fraction 2% after washing with dilute HCl.

碳纳米管阵列研究进展

WEI Fei, ZHANG Qiang, QIAN Wei-zhong, XU Guang-hui, XIANG Rong, WEN Qian, WANG Yao, LUO Guo-Hua

2007, 22(03): 271-282.

Abstract(2075)

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Abstract:
Current research advances on CNT arrays are reviewed with an emphasis on synthesis. The growth mechanism, structure modulation and mass production of CNT arrays are also discussed. Various applications of the as-grown CNT arrays, CNT yarns and dispersed CNTs from the arrays in a composite, strength enhancement and functional devices are also summarized. It is pointed that the research trend on CNT arrays should be emphasized for the large scale production of CNT arrays and their applications.

炭科学技术的研究现状与发展趋势——记Carbon 2007国际炭会议

LIU Chang, CHENG Hui-ming

2007, 22(03): 283-285.

Abstract(1835)

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Abstract:
The International Carbon Conference, Carbon 2007, was held in Seattle, USA, hosted by the American Carbon Society and Oak Ridge National Laboratory, during July 15-20, 2007. About 430 attendees participated in the conference, and 433 papers were accepted for discussion, including 4 plenary lectures, 16 keynote talks, 238 oral presentations, and 175 posters. The papers were mainly contributed by researchers from the USA, Japan, UK, China, France, Korea, Germany, and Spain, and were classified into the flowing topics: novel structures and forms of carbon materials, characterization of carbon materials properties, electrochemical applications of carbon materials, carbons for composite materials, active carbons etc. Studies on nanostructured carbons are quite active, and notable progress has been achieved on the electrochemical properties and biomaterials and medical applications of carbon materials.

第14届国际层间化合物会议在韩国首尔举行

LU Rui-tao, KANG Fei-yu

2007, 22(03): 286-288.

Abstract(2034)

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Abstract:
This report briefly introduces the 14th International Symposium on Intercalation Compounds (ISIC14) held in Seoul of Korea, June 12-15, 2007. More than 300 experts from 21 countries attended this symposium and presented 462 contributions. The presentations of ISIC14 covered a wide range of topics, including (1) nanocarbons, graphite (2) superconducting, magnetic and optical materials (3) electrochemical functional materials (lithium battery, supercapacitors, fuel cell) (4) transition metal chalcogenides (5) hydrogenstorage materials (6) cationic and anionic clays (7) nano composites (8) microporous and mesoporous materials (9) oxides, phosphates, and other layered materials (10) nanomaterials including clathrates and clusters (11) biomaterials and drug delivery systems. ISIC15 will be held in Beijing, China, May 12-15, 2009. The organizing chairman of ISIC15 will be Prof. Feiyu Kang from Tsinghua University.

2007 Vol. 22, No. 03

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