2011 Vol. 26, No. 4

  Previous Issue | Next Issue 
Developing carbon materials targeted for applications
—A summary on the annual world conference on carbon, Carbon2011
LI Feng, LONG Dong-hui
2011, 26(4): 241-245.
Abstract(2006) PDF(1915)
Abstract:
The 2011 Annual World Conference on Carbon (Carbon 2011) was held in Shanghai, China, during 24-29 July, 2011. This conference was hosted jointly by East China University of Science and Technology, University of Shanghai for Science and Technology, and Institute of Coal Chemistry Chinese Academy of Sciences. About 800 attendees from 42 countries/regions participated in this conference, and 797 papers were accepted for presentation, including 5 plenary lectures, 42 keynote lectures, 280 oral presentations, and 470 posters, involving 10 topics: graphene; nanocarbon, carbon for energy storage and conversion, porous carbon and adsorption, carbon fiber and composites, precursor/carbonization and graphitization, computation and modeling, bio-carbon and safety, novel experimental techniques and characterization, bulk carbon and industrial applications. Research and development of nanocarbons are quite active and in particular, graphene received tremendous interest. Rapid progress has also been made on the electrochemical properties, energy conversion and energy storage applications of carbon materials.
Carbon for energy storage and conversion
KANG Fei-yu, HE Yan-bing, LI Bao-hua, DU Hong-da
2011, 26(4): 246-254.
Abstract(2419) PDF(2488)
Abstract:
The current research status of carbon material and the future development tendency in the energy storage and conversion fields are reviewed. Carbon demonstrates many excellent physical and chemical properties owing to its unique structures and morphology. It has been widely used in energy storage and conversion devices. Carbon is a key material of catalyst supports，bipolar plates and gas diffusion layers in fuel cells, transparent conductive films and as a core material to form the carbon-silicon or all carbon p-n heterojunctions in solar cells. Carbon is also a significantly important electrode material in lithium ion batteries and supercapacitors. Moreover, Carbon has wide applications in the fields of heat storage, gas storage, nuclear energy, wind energy, and so on. It is suggested that carbon might be developed to be nano-structured and ordered in composites so that its performance in energy storage and conversion can be improved by functionalization and controlled synthesis.
Preparation of iron oxide nanoparticles supported on magnesium oxide for producing high-quality single-walled carbon nanotubes
Wei-Wen Liu, Azizan Aziz, Siang-Piao Chai, Abdul Rahman Mohamed, Ching-Thian
2011, 26(4): 255-261. doi: 10.1016/S1872-5805(11)60080-2
Abstract(3324) PDF(1323)
Abstract:
Fe3O4 nanoparticles with a narrow diameter distribution having an average diameter of 10.33nm±2.99nm (average diameter±standard deviation) were prepared by a precipitation method. The Fe3O4 nanoparticles were supported on MgO by mixing the MgO nanopowder with the required amount of Fe3O4 nanoparticles in water under extensive sonication. Single-walled carbon nanotubes (SWCNTs) were synthesized by the chemical vapor deposition (CVD) of methane over the Fe3O4/MgO catalyst. Transmission electron microscopy showed that a large number of SWCNT bundles of nearly uniform diameter were produced by the CVD method. The average diameter of the produced SWCNTs was ca. 1.22nm. Thermogravimetric analysis showed that the weight loss was approximately 19% by oxidation of carbon in the temperature range of 400-680℃. The ratio of the intensity of the D-band to the G-band was 0.03, indicating that the SWCNTs were well-graphitized.
Electrocatalytic oxygen-reduction reaction on a carbon nanofiber/carbon paper composite
ZHENG Jun-sheng, WANG Xi-zhao, FU Rong, LI Ping, YANG Dai-jun, LU
2011, 26(4): 262-270. doi: 10.1016/S1872-5805(11)60081-4
Abstract(3038) PDF(1247)
Abstract:
A carbon nanofiber/carbon paper (CNF/CP) composite was synthesized directly on CP by a catalytic chemical vapor-deposition method, and the physicochemical properties of and oxygen-reduction reaction (ORR) on this composite were investigated. Scanning electron microscopy shows that the CNFs are uniformly distributed on the CP, and high-resolution transmission electron microscopy results show that the CNFs have a narrow size distribution. The CNF/CP composite has a large surface area, and its mesoporous character is confirmed by N2 physisorption. Raman spectrum studies show that the CNF/CP composite has a high ratio of edge atoms to basal atoms compared with that of CP. From cyclic voltammetry studies, the CNF/CP composite was found to be more active than CP in terms of ORR, which may be due to the contribution from the CNFs. The CNF/CP composite shows a higher exchange current density and more positive equilibrium potential than CP, as verified by Tafel analysis. Moreover, linear-sweep voltammetry confirms that ORR on the CNF/CP composite is conducted through a two-electron reaction pathway.
Preparation of a plate-like C/C composite membrane for gas separation
WANG Tong-hua, ZHENG Qing-chun, LI Lin|　CHEN An-liang, CAO Yue
2011, 26(4): 271-277.
Abstract(2970) PDF(1406)
Abstract:
Plate-like C/C composite membranes were prepared by spin-coating pyromellitic dianhydride-oxydianiline (PMDA-ODA) polyamic acid (PAA) on membrane supports from bituminous coal and anthracite. The effects of coating time, the properties and pretreatment of the membrane supports, and modification by a blending surface modifier in PAA on the gas separation performance of the membranes were investigated. Scanning electron microscopy was used to characterize the microstructure of the membranes. Results indicate that the single gas permeation rates of the membranes decrease and selectivities increase with an increase in coating time. The gas separation performance of the bituminous coal-based membranes is better than that of anthracite-based ones. The pre-immersion treatment of anthracite supports can greatly improve the gas permeation rate of the membranes. A surface modifier improves the binding strength between the carbon plate and PAA, and membranes with the surface modifier additive exhibit molecular sieving after only one spin-coating. For the bituminous coal-based membranes, the selectivities of H2/N2, CO2/N2, O2/N2 are 94.3, 18.3, 10.2 respectively, and the selectivity for O2/N2 of air is 10.8 with the O2 permeation rate of 4.99×10-9 mol · m-2 · s-1 · Pa-1. The O2 concentration can reach 74.4% after one enrichment.
Effect of interface properties on the mechanical performance of carbon fiber/Mg composites fabricated by powder metallurgy
REN Fu-zhong|　GAO Jia-cheng|　LI wei, ZHANG Min, TAN Zun
2011, 26(4): 278-286.
Abstract(2829) PDF(1322)
Abstract:
Carbon fiber/magnesium composites were fabricated by powder metallurgy techniques using short carbon fibers electrolessly coated and uncoated by nickel as reinforcement and pure magnesium powder as matrix. SEM- EDS, TEM, XRD and tensile tests were used to characterize their interfacial morphology, elemental composition, phase composition and mechanical properties. Results showed that the carbon fibers were uniformly distributed in the composites and were preferentially oriented parallel to the extrusion direction. The interfacial bonding between carbon fibers and magnesium was improved by the nickel coating. The improvement was achieved by a reaction between the nickel coating on the fibers and magnesium to form Mg2Ni. The reinforcing effect of the nickel-coated carbon fibers was achieved by interfacial load transfer as evaluated by comparing the measured yield strengths with the theoretical values.
Effect of graphitization parameters on the residual stress in 4D carbon fiber/carbon composites
SHI Hong-bin, TANG Min, GAO Bo, SU Jun-ming
2011, 26(4): 287-292. doi: 10.1016/S1872-5805(11)60082-6
Abstract(3012) PDF(1609)
Abstract:
A representative volume element model was proposed for C/C composites with the fibers oriented in four different directions. Three of the fiber directions were coplanar, at 120° to each other, and the fourth was perpendicular. The element truly reflects the orientations of the carbon fibers and matches the actual configuration of the composites. Based on the model and computational mesoscopic mechanics, the residual thermal stress distribution of the material at different graphitization temperatures, cooling rates, and interface stiffnesses was obtained using a finite element method. The residual thermal stresses of the composite from a low-graphitization temperature or with low interface stiffness are lower than those from a high-graphitization temperature or with high interface stiffness. The higher the cooling rate, the higher the residual thermal stress.
Synthesis of ordered mesoporous carbons by non-aqueous solvent evaporation method
LI Tie-hu, WANG Xiao-xian, JI Yong-bin, JIN Wei, LIN Qi-lang
2011, 26(4): 293-298.
Abstract(2768) PDF(1204)
Abstract:
Ordered mesoporous carbons (OMCs) with well-developed mesopores were synthesized using evaporation-induced self-assembly (EISA). The triblock copolymer P123/phenol-resin/silica composites were prepared by EISA using tetraethyl orthosilicate as the inorganic source, P123 as the structure directing agent and phenol-resin as the carbon source. OMCs were obtained by the carbonization of the composites, followed by the removal of the silica template with a mass fraction 10% HF aqueous solution. For comparison, another OMC was synthesized by using ordered silica as a hard template and impregnated sucrose as the carbon precursor. The samples were characterized by scanning and transmission electron microscopy and N2 sorption. Results indicated that the OMCs had an ordered hexagonal structure with a narrow distribution of mesopores. The optimized OMC was obtained using a P123/phenol-resin mass ratio of 1∶0.25. Compared with the OMCs synthesized by the hard template method, the new OMCs had fewer micro- and macropores.
Adsorptive removal of phosphate from aqueous solutions using activated carbon loaded with Fe(III) oxide
SHI Zhong-liang, LIU Fu-mei, YAO Shu-hua
2011, 26(4): 299-306. doi: 10.1016/S1872-5805(11)60083-8
Abstract(3471) PDF(1493)
Abstract:
An composite adsorbent for the removal of phosphate from aqueous solutions was synthesized by loading iron oxide onto activated carbon. The adsorbent can be separated from the medium by a simple magnetic procedure owing to the magnetic properties of the iron oxides. The properties of the composite were investigated by nitrogen adsorption, scanning electron microscopy and X-ray diffraction. The adsorption of phosphate ions by the composite adsorbent and the activated carbon was compared in batch experiments. The composite adsorbent showed fast adsorption rates and high adsorption capacities and its adsorptive performance for phosphate ions was dependent on the pH value, iron content and anion concentration. The adsorption capacities of phosphate ions at pH 3.0 were 98.39mg/g for iron oxide/activated carbon composite and 78.90mg/g for activated carbon. The adsorptive isotherms for phosphate ions with activated carbon and the composite adsorbent all match the Freundlich model better than the Langmuir model. The adsorption kinetic data could be well described by the Lagergren pseudo-second-order kinetic equation. The adsorption by the composite adsorbent is endothermic for phosphate ions.
The electrochemical performance of a multi-wall carbon nanotube/activated carbon mixture as the electrode of electric doublelayer capacitors analyzed by electrochemical impedance
GENG Xin, LI Feng, WANG Da-wei, CHENG Hui-ming
2011, 26(4): 307-312.
Abstract(3292) PDF(612)
Abstract:
Activated carbon was prepared from petroleum coke by chemical activation. Multi-walled carbon nanotubes (MWCNTs) were mixed with the activated carbon to form the electrode material of electric double layer capacitors. According to the relative values of impedance and capacitance in electrochemical impedance, the available capacitance and energy dissipation from resistance were evaluated. Results showed that the real part of the capacitance for this mixture was higher than for activated carbon alone when activated carbon was mixed with a mass fraction 3%-15% MWCNTs. With the increase of MWCNT content, the imaginary part of the capacitance and its percentage decreases while the real part of capacitance and its percentage increases. It was revealed that the efficiency of energy storage was improved, the relaxation time constant was decreased, the characteristic of capacitance response versus frequency was improved and the electrode resistance was decreased by the addition of MWCNTs to activated carbon.
Effect of microwave-treatment time on the properties of activated carbons for electrochemical capacitors
HE Xiao-jun, WANG Ting, QIU Jie-shan, ZHANG Xiao-yong, WANG Xiao-ting, ZHEN
2011, 26(4): 313-319. doi: 10.1016/S1872-5805(11)60084-X
Abstract(3377) PDF(1282)
Abstract:
Activated carbons (ACs) made from petroleum coke by KOH activation were further treated by microwaves to investigate the effect of microwave-treatment time on the pore structure, the surface properties (functional groups) and the electrochemical properties of the as-made ACs for electrochemical capacitors (ECs). Results show that the specific capacitance and the equivalent series resistance of microwave-treated ACs become smaller with a decrease in the Brunauer-Emmett-Teller surface area and the total pore volume (vt) of the treated ACs. Compared with the AC sample heated at 1073K for 1h by a conventional heating method, the AC sample treated by microwaves at 700W for only 7min has a pore size distribution with a high (meso- and macropore volume)/vt ratio and a high carbonyl content, and exhibits a high energy density and powder density as an electrode of ECs. This has clearly shown that the microwave-treatment is a simple and efficient approach to obtain high-performance ACs for ECs.
Professor Wanci Shen and his research activity in carbon materials
KANG Fei-yu
2011, 26(4): 320-320.
Abstract(1509) PDF(1592)
Abstract:

Address： 27 Taoyuan South Road, Yingze District, Taiyuan City, Shanxi Province, ChinaPostCode：030001

Phone/Fax：0351-2025254

Email： tcl@sxicc.ac.cn

Copyright © 2021 Editorial Office of New Carbon Materials. All Rights Reserved This system consists of Beijing Renhe Information Technology Co. Ltd   百度统计