2010 Vol. 25, No. 06

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Research frontiers and trends in graphene research
WANG Li, PAN Yun-tao
2010, 25(06): 401-408.
Abstract(3828) PDF(4376)
Abstract:
This article analyzes graphene-related papers using the Thomson data analyzer according to publication year, country, organization, subject and research focus, and compares the research situation of China with that of the international community in this field. We find that research relevant to graphene has developed very rapidly since 2005, which is mainly in the fields of polymer physics, materials science and applied physics. The main countries that are engaged in the study of graphene are the United States, China, Japan, Britain, Germany, etc. The hot topic in this field is the properties of graphene such as electronic conductivity and thermal conductivity, preparation methods and composite materials. In the recent two years, China has paid great attention to graphene research, but is far behind the leading countries.
Carbonization under pressure
Michio INAGAKI, Ki Chul PARK, Morinobu ENDO
2010, 25(06): 409-420. doi: 10.1016/S1872-5805(09)60042-1
Abstract(2686) PDF(2951)
Abstract:
Carbonization under pressure was reviewed by being classified into three routes: carbonization of the precursors under pressure of their decomposition gases, carbonization under hydrothermal conditions, and reduction of pressu~rized CO2. Carbon materials with different structures and nanotextures were formed with relatively high yield under pressure, but obtained as a mixture in most cases. In this review, the formation conditions of carbon spheres in pure and an individually separated state are discussed by focusing on the temperature-pressure conditions and the chemical composition of the precursors used.
Improvement of the electrochemical properties of sulfur cathode materials with multiwalled carbon nanotubes
WU Feng, WU Sheng-xian, CHEN Ren-jie, CHEN Shi, WANG Guo-qing
2010, 25(06): 421-425.
Abstract(2597) PDF(1713)
Abstract:
In order to improve electronic conductivity and prevent dissolution of sulfur into the electrolyte, composite materials based on elemental sulfur and multiwalled carbon nanotubes (MWCNTs) with high specific surface area and strong absorbability as an inactive additive were prepared by a completely airtight step-wise heat synthesis method. X-ray diffraction, scanning electron microscopy and specific surface area measurements all indicated that elemental sulfur was distributed evenly throughout the MWCNTs. The electrochemical tests showed that the initial discharge specific capacity of an elemental sulfur positive electrode with MWCNTs was 1487.0mAh · g-1 and the utilization of electrochemically active sulfur was 88.9%. The specific capacity remained as high as 913.7mAh · g-1 after 50 cycles which showed that the electrochemical properties of the sulfur cathode with the addition of MWCNTs were remarkably improved.
Modification of hydroxylated multi-walled carbon nanotubes with a block copolymer
WANG Guo-jian, WANG Ke-wei, QIU Jun
2010, 25(06): 426-430.
Abstract(2826) PDF(1472)
Abstract:
A novel approach was used to improve the dispersibility of multi-walled carbon nanotubes (MWCNTs) in a solvent. Vinyl-functionalized MWCNTs were prepared by the esterification of acrylic acid with hydroxylated MWCNTs. The block copolymer, polystyrene-b-hydroxyethyl methacrylate was synthesized by means of atom transfer radical polymerization. Then the block copolymer was attached to the surface of the MWCNTs through an addition reaction. The products were characterized by FTIR, TGA and TEM. Results indicated that the copolymer was attached to the surface of the MWCNTs by covalent bonds with a content of 42.9%, i.e. every 277 carbon atoms were grafted with a block copolymer chain. The resulting products had a good dispersibility in ethanol.
Structure evolution of carbon microspheres from solid to hollow
YANG Yong-zhen, LIU Xu-guang, LUO Qiu-ping, JIN Lin, XU Bing-she
2010, 25(06): 431-437.
Abstract(2650) PDF(1582)
Abstract:
Hollow carbon microspheres, several micrometers in diameter, were prepared from solid carbon microspheres by a simple oxidation-in-air process. The morphology and structure of these products were characterized by field-emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and thermogravimetry. Results indicate that heat treatment temperature in air plays a key role in the evolution of the cavity size and wall thickness of the hollow carbon microspheres with poor graphitization, and high heating temperature leads to a thin wall thickness and large inner diameter. A proposed formation mechanism reveals that the hollow carbon microspheres are formed as a result of the effect of curvature and crystallinity, i.e. the inner part of solid carbon microspheres has a large curvature and a low crystallinity, which is much more easily oxidized to form hollow carbon microspheres when subjected to air oxidation.
Preparation of carbon spheres from potato starch and its stabilization mechanism
ZHAO Shuo, WANG Cheng-yang, CHEN Ming-ming, SHI Zhi-qiang, LIU Na
2010, 25(06): 438-443. doi: 10.1016/S1872-5805(09)60044-5
Abstract(2773) PDF(1695)
Abstract:
Carbon spheres perfectly retaining the original morphology of potato starch were prepared by a two-step process including stabilization and carbonization. The potato starch was first stabilized at 210℃ under air, and the stabilized samples were then carbonized at 600℃ for 1h under N2 atmosphere. In the process, stabilization treatment was the main step. The mechanism of stabilization was investigated by thermogravimetric analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and differential scanning calorimetry, and the morphology of the carbon spheres was characterized by scanning electron microscopy (SEM). Results show that during stabilization, the loss of water and the occurrence of decomposition and condensation reactions result in the destruction of the crystallite structure in the original potato starch. Thus, during the carbonization step, further intermolecular cross-linking makes microcrystalline melting very difficult. This promotes the formation of monodispersed carbon spheres. The SEM results show that only if the potato starch undergoes adequate stabilization treatment (e.g., 12h) before carbonization, can the carbon spheres perfectly retain the original shape of the potato starch.
Combustion and thermal decomposition of ammonium dinitramide catalyzed by carbon nanotubes
LI Xiao-dong, YANG Rong-jie
2010, 25(06): 444-448.
Abstract(2768) PDF(1430)
Abstract:
The catalysis of carbon nanotubes (CNTs), carbon nanotubes supporting ferric oxide (Fe2O3/CNT) and carbon nanotubes supporting iron and copper (Fe · Cu/CNT) on the combustion and thermal decomposition of ammonium dinitramide (ADN) were investigated through burning rate measurements and TG analysis. Results show that all three catalysts increase the burning rate of ADN. The burning rates are related to combustion pressure by a power function and the pressure exponents decrease with the amount of catalyst for all of the three catalysts. When 3mass% of catalyst is used the burning rate of ADN at 4MPa increases from 30.49 to 50.59, 39.72 and 38.79mm · s-1 and the pressure exponents decrease from 0.81 to 0.36, 0.67 and 0.75 for the CNTs, Fe2O3/CNTs and Fe · Cu/CNTs respectively, TG tests show that all three catalysts decrease the thermal decomposition temperature of ADN. The primary thermal decomposition temperatures of ADN decrease to 18.3℃, 12.1℃, and 11.6℃ for the CNTs, Fe2O3/CNTs and Fe · Cu/CNTs respectively when 1mass% catalyst was added to ADN.
Preparation of biological activated bamboo charcoal and its use to remove quinoline from waste water
ZHU Li-si, HUANG Zheng-hong, WEN Dong-hui, KANG Fei-yu
2010, 25(06): 449-453.
Abstract(2268) PDF(1542)
Abstract:
A strain of bacterium (BC027) for quinoline degradation was inoculated on an activated bamboo charcoal (ABC) substrate to obtain biological activated bamboo charcoal (BABC). SEM micrographs showed that microbe can grow well on ABC. The quinoline removal by the BABC was divided into 3 stages, adsorption, interim and degradation. The degradation played a key role in these stages, which was related to the optical density of bacteria in the solution. In contrast, the adsorption of quinoline on BABC only happened at the first stage. The BABC exhibited higher treatment capacity and longer use life than did ABC.
Effect of anodic oxidation on the properties of Ni-coated carbon fibers produced by electrodeposition
LU Xiao-xuan, LU Chun-xiang, YANG Yu, ZHOU Pu-cha, AN Feng
2010, 25(06): 454-459.
Abstract(2446) PDF(1522)
Abstract:
PAN-based carbon fibers were continuously treated by anodic oxidation followed by electrodeposition of Ni on their surface. The influence of anodic oxidation on mechanical properties，surface morphology，amount of surface acidic groups and growth mode of the Ni coating were studied by SEM , XRD , TG and conductometric titration. Results showed that the total amount of surface acidic groups on the oxidized carbon fibers is about 10times as large as that of the untreated ones and the tensile strength of carbon fibers decreased slowly at first and then quickly with increasing depth of oxidation. The growth mode of the Ni coating changed from a Volmer-Weber mode to a Frank-van der Merwe mode and the grain size of the Ni coating decreased from 14.5 to 11.2nm for the untreated and treated carbon fibers respectively. The oxidation resistance of the carbon fibers was improved by the Ni coating. The initial oxidation temperature of the Ni-coated treated-carbon fibers with anodic oxidation is about 50℃ higher than that of the Ni-coated carbon fibers without the oxidation. Appropriate oxidation could improve the adhesion between the Ni coating and the carbon fibers.
The surface chemistry of pitch-based spherical activated carbon（PSAC）and the effect of gas-oxidation treatment on its adsorption performance
LIU Chao-jun, LIANG Xiao-yi, TENG Na, LIU Xiao-jun, LONG Dong-hui
2010, 25(06)
Abstract(2992) PDF(1620)
Abstract:
Pitch-based spherical activated carbon (PSAC) was modified by gas mixtures of nitrogen and oxygen. Nitrogen adsorption was used to obtain the pore structure of the PSAC. The phenol adsorption performance of the PSAC before and after modification was investigated. Results showed that there is no obvious texture change of PSAC after air oxidation. When the PSAC was modified with a gas mixture having an oxygen content of 20% for 5h at 400℃ and 450℃, the surface acidic groups increased from 0.11 to 1.22, 1.60meq/g, while basic groups decreased from 0.52 to 0.03, 0.02meq/g, respectively. The adsorption capacity of phenol on the PSAC decreased as the surface acidic groups increased because its wettability was improved. Water molecules were more competitive for the adsorption sites than the adsorbate in such a situation. The adsorption isotherms of phenol on PSAC changed from type L to type S with an increase of surface acidic groups.
Properties of mesoporous carbons prepared from different carbon
TANG Zhi-hong, HE Xing, SONG Yan, LIU Lang, GUO Quan-gui, YANG Jun-he
2010, 25(06): 465-469. doi: 10.1016/S1872-5805(09)60045-7
Abstract(2842) PDF(1506)
Abstract:
Mesoporous carbons (MCs) with high-specific surface area and pore volume were synthesized from different carbon precursors (thermosetting phenol resin (TPR), mesophase pitch (MP), and polyacrylonitrile (PAN)) by using nanosize silica particles as a template. The influence of carbon precursors on the properties of as-prepared MCs was investigated by nitrogen adsorption, elemental analysis, and X-ray photoelectron spectroscopy. Results indicated that the pore structure as well as the surface chemical character of the resultant MCs differed greatly despite the preparation conditions being the same. Because the thermal stability of MP was higher and the dispersion ability of silica particles in MP/pyridine solution was poor, MC prepared from MP contained fewer micropores and mesopores compared with that prepared from TPR. In addition, MC derived from PAN had abundant nitrogen functional groups.
Functionalization of CNTs using plasma-induced graft polymerization and the properties of their composites with epoxy resin
JIA Run-ping, TAO Li, TENG Na
2010, 25(06): 470-474.
Abstract(2748) PDF(1475)
Abstract:
Plasma-induced graft polymerization was used to modify carbon nanotubes (CNTs), in which maleic anhydride (MAH) was used as polymeric monomer and argon as plasma source. The polymer film-modified CNTs (p-CNTs) were introduced into epoxy resin (EP) to obtain p-CNT/EP composites and their effects on EP properties were studied. The p-CNTs were characterized by FTIR and scanning electron microscopy. Results show that maleic anhydride can be graft polymerized onto the surface of CNTs using the plasma technique, forming a uniform polymaleic anhydride (PMAH) film. The mechanical properties of EP were greatly improved by adding p-CNTs.
Effect of impregnation on the pore structure of a tubular carbon membrane
ZHANG Yong-gang, LU Ming-chao
2010, 25(06): 475-478. doi: 10.1016/S1872-5805(09)60046-9
Abstract(2336) PDF(1437)
Abstract:
To adjust and control the porous structure in the inner face of a tubular carbon membrane (TCM), impregnation methods were used, and the effects of impregnation on the pore size distribution were analyzed by adjusting impregnant concentrations and impregnation times. SEM images show that the impregnation treatment can repair the pore defects on the TCM surface. Data on the micropore size distribution indicate that the pore size of the TCM becomes smaller and its distribution becomes narrower with increasing impregnant concentrations and impregnation times, which indicates that impregnation conditions can be used to adjust the pore size and structure of the TCM.
Introduction to the ninth cross strait symposium on advanced carbon materials
Tai Nyan-hwa
2010, 25(06): 479-480.
Abstract(1785) PDF(1588)
Abstract:
This report is of the Ninth Cross Strait Symposium on Advanced Carbon Materials, which was held at National Tsing-hua University in Hsin-Chu, Taiwan, Oct. 4-6, 2010. More than 60 scientists, including 33 experts from Mainland China, attended the symposium. Forty-two papers including four plenary lectures were presented. The symposium involved six topics including catalytic properties of carbon nanomaterials, microstructure, processing, composites, graphene as well as bio-related carbon materials and new applications. The four plenary lectures focused on the synthesis and characterization of graphene, catalytic behavior of carbon nanomaterials, and novel design of the diffusion layer in a fuel cell.

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