新型炭材料

XIE Hua-qing, Mansoo-Choi

2008, 23(01): 1-6.

Abstract(2404)

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Abstract:
Hydrophobic surfaces of multi-walled carbon nanotubes (CNTs) were oxidized by boiling a mixture of CNTs and concentrated acid. A selforganized pellet which can be reversibly dispersed was produced by dehydrating the oxidized CNT solution. Scanning electron microscope pictures showed that the pellet consisted of highly aligned nanotubes. Fourier transformation infrared and X-ray photoelectron spectroscopy indicated that oxygencontaining surface groups were introduced during the acid oxidation. Although an increased number of defects was shown by Raman spectroscopy, Xray diffraction indicated that graphene layer organization remained after treatment. Thermal stability of treated CNTs was investigated and comparisons between pristine, treated, and heated CNTs were made. This wellpacked and soluble pellets can provide ideal samples to study bulk CNT nanostructured materials and CNT composites.

单壁碳纳米管-DNA复合物的微观结构和电化学性质

YANG Liu-quan, XIANG Dong-ya, YANG Quan-hong, ZHAO Zhuo

2008, 23(01): 7-11.

Abstract(4297)

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Abstract:
The microstructure and electrochemical properties of hybrids, combining singlewalled carbon nanotubes (SWCNTs) and DNA, were investigated. TEM images of the SWCNTDNA hybrids show that most bundled SWCNTs in the starting materials are isolated into individual ones during the sonicationpromoted selfassembly. AFM observation further indicates that the sidewalls of SWCNTs are helically wrapped by DNA, which results in stable SWCNTDNA complexes. The catalyst particles are totally removed during this selfassembly process, thus the SWCNTs are also purified. The electrochemical properties of the SWCNTs are substantially improved due to the hybridization of DNA and the specific capacitance of the SWCNTDNA hybrids is increased by of 117.9% compared to the parent SWCNTs.

炭纤维表面生长碳纳米管

ZHAO Jian-guo, LIU Lang, GUO Quan-gui, SHI Jin-li, ZHAI Geng-tai, SONG Jin-ren

2008, 23(01): 12-16.

Abstract(2603)

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Abstract:
The growth of carbon nanotubes on the surface of carbon fibers by chemical vapor deposition was investigated and their microstructure was studied by scanning electron microscopy. Results show that grooves on the surface of carbon fibers, which can load catalysts, are locations for the growth of the nanotubes. Cobalt is the best catalyst among Fe, Co, and Ni. Carbon nanotubes are of large diameter when the catalyst concentration is high. Carbon nanotubes cannot be distributed evenly on the whole surface when the concentration of catalysts is low. The optimum catalyst concentration of cobalt nitrate is 0.05mol/L.

选择冲洗法在碳纳米管内部填充金属粒子

FU Qiang, Gisela Weinberg, SU Dang-sheng

2008, 23(01): 17-20.

Abstract(2652)

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Abstract:
A straightforward method is presented to produce catalyst particlefilled carbon nanotubes. Based on capillarity and surface tension, a simple strategy was developed to selectively fill carbon nanotubes with Fe, Co, and Ni species using a twostep method consisting of impregnation and selective washing. By chosing the impregnation and washing solution properly, metal particles are produced exclusively inside the nanotubes. STEM and SEM investigations confirm the location of these metal particles is only inside the carbon nanotubes.

炭纤维增强轻质矿粉混凝土的热电行为

Bahar Demirel, Salih Yazicioglu

2008, 23(01): 21-24.

Abstract(2560)

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Abstract:
Carbon fiber reinforced concrete can be used to sense temperature owing to the Seebeck effect caused by the p-type conductivity of short carbon fibers. Both the temperature sensing ability of the carbon fiber reinforced lightweight concrete and the influence of mineral admixtures on the Seebeck effect were investigated by measuring the thermo electric power of six Portland cementbased concretes with or without carbon fibers or mineral admixtures (fly ash, silica fume). It was found that the carbon fiber reinforced lightweight concretes had a Seebeck effect similar to the carbon fiber reinforced normal concrete, but their Seebeck coefficients were decreased by mineral admixtures. Carbon fiber reinforced lightweight concrete with mineral admixtures can be used as a thermal sensor in buildings.

活性可控聚合制备水溶性单壁碳纳米管

WANG Guo-jian, WANG Yao, HUANG Si-zhe, LIU Lin

2008, 23(01): 25-29.

Abstract(2677)

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Abstract:
Water-soluble singlewalled carbon nanotubes (SWCNTs) were prepared by grafting water-soluble polymer to their surface by a kind of controlled/living radical polymerization. Reversible addition-fragmentation chain transfer polymerization was used for this purpose using acrylic acid as a monomer and a dithio compound, PhCS(S)CH(CH3)Ph, as a chain transfer agent that was covalently bonded to the surface of the SWCNTs. Results showed that poly (acrylic acid) (PAA) was covalently connected to the surface of the SWCNTs and the resultant product, PAA grafted SWCNTs, had a high solubility in water.

天然石墨球-热解炭核壳结构的制备及电化学性能研究

LIU Shu-he, YING Zhe, WANG Zuo-ming, LI Feng, BAI Shuo, WEN Lei, CHENG Hui-ming

2008, 23(01): 30-36.

Abstract(2579)

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Two kinds of modified natural graphite (MNG) spheres with a pyrolytic carbon shell on smooth or granular surface were obtained using fluidized bed chemical vapor deposition of acetylene by adjusting the reaction parameters. The core of the MNG has a highly ordered graphite structure and the shell has a disordered structure. Compared with natural graphite (NG) spheres, MNG with a coreshell structure shows improved first cycling efficiency and cyclability. Especially, the MNG spheres with a granular surface possess 84% retention of the first discharge capacity after 41cycles, owing to effective decrease of the contact resistance and increase of contact area between the MNG spheres.

热处理活性半焦的表面性质和 SO2脱除活性

SHANGGUAN Ju, LI Chun-hu, MIAO Mao-qian, YANG Zhi

2008, 23(01): 37-43.

Abstract(2216)

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Abstract:
The activity of SO2 removal by activated semi-coke is influenced by the precursor and surface modification processes. Raw semi-coke was modified by heat treatment at 800℃ in a nitrogen flow, and its activity for SO2 removal was tested in a fixed bed reactor. The surface chemical properties of both raw semi-coke and activated semi-coke were characterized by acidbase titration, XPS, and FTIR. Graphitic carbon was the major component of carbon functional groups in the surface of both raw semicoke and activated semi-coke. Surface C=O groups in the forms of ketone, lactone, carbonyl, or quinone were the main surface oxygen functional groups, and pyrrolic and/or pyridon-N groups were the main nitrogen functional groups in raw semi-coke. The heat treatment resulted in the decomposition of surface oxygen functional groups and the redistribution of surface oxygen and nitrogen functional groups. The content of the surface carbon groups, such as C=O decreased dramatically after heat treatment. However, the content of surface oxygen functional groups, such as ethers and chemisorbed oxygen or water increased on the surface of activated semi-coke. The number of pyridinelike structures was increased by the removal of pyrrolic and/or pyridonN groups in the activation process. The increase of ethers group and π - π* transitions in aromatic systems, and the change of the nitrogen functional groups increased the surface basicity for activated semicoke. Activated semicoke had the higher activity for SO2 removal than did raw semicoke. The surface features influencing the activity for SO2 removal for activated semi-coke may be ethers, aromatic carbons and nitrogen functional groups with basicity.

利用电沉积Ni纳米晶制备无缠绕阵列碳纳米管

BAO Qiao-liang, RAN Xiang, ZHANG Han, QI Xiang, FU Qiang, PAN Chun-xu

2008, 23(01): 44-50.

Abstract(3168)

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Abstract:
Wellaligned nontangled carbon nanotubes (CNTs) were grown in ethanol flames on a nanocrystalline Ni layer that was electrodeposited on a Cu alloy substrate using periodic reverse pulse plating. The morphologies and microstructures of the nanocrystalline layers and the CNTs were characterized by XRD, SEM, TEM, AFM and laser Raman spectroscopy. It was found that a large area of vertically aligned CNTs with uniform density could be produced with high repeatability by controlling the thickness of the Ni nanocrystalline layer and time in the flame. A low electrodeposition time was favorable for the formation of thin layer nanocrystalline Ni with high local roughness and high catalytic activity on which wellaligned CNTs were generated with overcrowded growth that prevented them from becoming tangled. A low aspect ratio of CNTs was needed to keep them from tangling, and this could be adjusted by controlling the pulse electrodeposition parameters to form the desired catalyst particles. The best CNTs can be produced by passing ethanol through a nanocrystalline Ni layer supported substrate at 600℃ for 1 min that had been electrodeposited at an output pulse frequency of 154Hz with duty cycle of 38.5% for 1min.

粒状增强体种类对沥青基炭复合材料性能的影响

GUO Ling-jun, LI He-jun, LI Ke-zhi, WANG Chuang

2008, 23(01): 51-57.

Abstract(2707)

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Abstract:
Pitchbased carbon composites (PCCs) reinforced by three granular cokes, metallurgical coke, No. 1 pitch coke and No.2 pitch coke, were prepared under an air atmosphere using a hydraulic press and new mold pressing and semicarbonization shaping technology. The asfabricated PCCs were treated in turn by quick baking, onetime densification and graphitization at 2373K, and three corresponding samples were obtained. The effect of the type of granular coke used as reinforcement on the volume density and mechanical properties of the PCCs was studied by a materials testing machine, SEM, and XRD. Results indicate that the compressive strength of the PCCs is closely related to the surface morphology, microstructure, and compressive strength of the granular cokes. A higher compressive strength, coarser surface and more open porosity of granular cokes induce higher reinforcement to the composites. The PCCs can be obtained through baking, densification, and graphitization. The compressive strength of the PCCs fabricated using metallurgical cokes is the highest with those from No.2 pitch coke in the middle and those from No. 1 pitch coke the lowest. The granular cokes not only greatly influence the mechanical properties of the PCCs, but also, to some extent, pass their original strength to their descendants.

炭气凝胶负载PtRu纳米颗粒用作甲醇氧化催化剂

DU Hong-da, LI Bao-hua, GAN Lin, WU Peng, KANG Fei-yu, ZENG Yu-qun

2008, 23(01): 58-62.

Abstract(2846)

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Abstract:
PtRu nanoparticles were loaded on carbon aerogels (CAs) by the ethylene glycol reduction method. TEM observations show that the PtRu particles are uniformly dispersed on CAs with a particle size of 3nm. Both cyclic voltammetry and constant potential show that the catalyst on CA with large pores has a high activity for methanol oxidation. The onset potential for methanol oxidation in cyclic voltammetry is independent of the kind of CA. The differences of catalyst activity are mainly attributed to the different mass transportation properties of the CAs. The methanol diffuses faster through larger pores, which makes it easy for methanol to arrive at the PtRu particles and improve the utilization rate of noble metals.

模板法制备沥青烯基有序中孔炭

ZHOU Ying, YU Gui-hong, ZHANG Yan, LI Jun-ning, QIU Jie-shan

2008, 23(01): 63-68.

Abstract(3893)

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Abstract:
Ordered mesoporous carbons (OMCs) were synthesized from asphaltene using a template carbonization method. The OMC material was studied by scanning and transmission electron microscopy, Xray diffraction, N2 adsorption and thermal gravimetric analysis. Results show that the asobtained OMC material with graphitic frameworkconfined ordered structure is a reverse replication of the template, which has a relatively high surface area of 562m2/g，large pore volume of 0.57 cm3/g and narrow pore size distribution centered at 3.57nm. The structure of the OMC is stable at 300℃ in air, showing good thermal stability. Electrical conductivity measurements show that the OMC material has an average electrical resistance of 0.16Ω•cm.

C/C复合材料显微结构的微米、纳米尺度研究

LIANG Jia-miao, ZHOU Geng-heng, HE Lian-long

2008, 23(01): 69-74.

Abstract(3010)

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Abstract:
The morphology, microstructure and graphitization degree of C/C composites fabricated by chemical vapor infiltration were studied by SEM, HRTEM, selected area electron diffraction and laser Raman spectroscopy. The pyrolytic carbons were rough laminar with a thickness from several 10nm to several 100nm, and were aligned parallel to the fiber axis and easily split and twinned by ion beam irradiation. A disordered zone with a thickness of about 15nm was also identified between the carbon fibers and the pyrolytic carbons, the formation of which may be dependent on the infiltration process. Both the carbon fibers and pyrolytic carbon had a low degree of graphitization and R(R=ID/IG+D’) decreased from the inner to the outer layers of the pyrolytic carbons.

石油沥青对乳化法煤沥青基炭微球的改性机理

XUE Yun-wei, YANG Chang-ling, LU Yong-gen, RONG Hai-qin, WANG Peng, PAN Ding

2008, 23(01): 75-80.

Abstract(2859)

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Abstract:
Coaltar pitchbased carbon microspheres were prepared by adding petroleum pitch using emulsifying pitchtoluene colloidal solution in polyvinyl alcohol (PVA) glycerol solution. To clarify the influence of pitch solubility in toluene and its affinity with the hydrophobic methylene groups of PVA on the sphere formation, petroleum pitch having a high affinity with methylene groups was added to the coal tar pitch in different proportions. A model was proposed to tentatively elucidate the sphere formation mechanism. It was found that petroleum pitch addition could improve the sphericity of pitch spheres by stabilizing the surfactant orientation on the interface between pitch molecules and dispersant. Adding petroleum pitch lowered the softening point of mixed pitch and an appropriate amount of addition was needed to ensure a high softening point of mixed pitch spheres above the reaction threshold temperature for airoxidative stabilization.

碳纳米管性质对填充镍结构的影响

LI Huan-ying, REN Xiu-bin, GUO Xiang-yun

2008, 23(01): 81-85.

Abstract(2359)

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Abstract:
A Monte Carlo method was used to study the effects of nanotube diameter, structure and interaction between the nanotube and nickel on the structure of encapsulated nickel. Results show that the structure of the encapsulated nickel is dependent on the nanotube diameter and concentric layered structures, with and without a single atomic chain, alternate with increasing nanotube diameter. In addition, the structure of nanotube and the interaction between the metallic nickel and the nanotube have no obvious influence on the structure of encapsulated nickel.

激光法制备碳质纳米材料

SUN Jing, HU Sheng-liang, DU Xi-wen

2008, 23(01): 86-94.

Abstract(2417)

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Abstract:
arbon nanometer materials with small size, high purity and various structures, synthesized by laser ablation have been widely applied in many fields. The processes of laser ablation in gases and liquids are discussed. Different physical chemistry phenomena exist in different media. The plasma zone generated by laser ablation of a solid target under a liquid is confined by the liquid. The temperature, pressure and density of the laserinduced plasma zone at the solidliquid interface are higher than those in a gaseous medium, which is suitable for the growth of nanocrystals, especially metastable nanocrystals such as diamond and carbon related materials. Carbon nanotubes could be prepared in gaseous and liquid media using a pulsed laser. Carbon nanotubes tend to grow in a gas, and nanodiamonds in a liquid. The size of nanodiamonds obtained from the graphite target is larger than that from a graphite suspension. The pulsedlaser irradiation of a graphite suspension can also be used to prepare linear carbon (carbyne).

碳化物衍生炭

2008, 23(01): 95-96.

Abstract(1782)

PDF(339)

Abstract:

2008 Vol. 23, No. 01

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