新型炭材料

Application of graphene derivatives in cancer therapy: a reviewWANG

Wang Xiao-Min, Zhang-Wei-Hua

2013, 28(5): 321-326.

Abstract(1351)

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Abstract:
Graphene derivatives generated by modifying the surface oxygen functional groups of graphene oxide have been widely investigated in recent years. Graphene derivatives possess excellent aqueous solubility and biocompatibility similar to graphene oxide, which are important in their biomedical application. Research progress on the use of graphene derivatives in biological imaging, drug carriers and photodynamic therapy of cancer is presented. Future efforts to improve their performance in cancer therapy are also proposed, such as lowering the toxic effects introduced by chemicals used in the preparation of the graphene derivatives, expanding the drug to include genes and proteins, and coupling photodynamic therapy with imaging.

pH-dependent size, surface chemistry and electrochemical properties of graphene oxide

WU Hui1, 　LU Wei1, 2, 　SHAO Jiao-jing1, 　ZHANG Chen1|WU Ming-bo3|　LI Bao-hua2|　Y

2013, 28(5): 327-335. doi: 10.1016/S1872-5805(13)60085-2

Abstract(1429)

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Abstract:
The size and surface chemistry of graphene oxide (GO) dispersed in an aqueous solution are tuned by adjusting the pH value of the parent GO hydrosol. This method is based on the protonation of the carboxyl groups on GO nanosheets (GONs) in an acidic environment and the partial removal of oxygen-containing functional groups in strong basic conditions. GONs with a high electrochemical activity can be obtained by tuning the pH-dependent sheet sizes and the fraction of functional groups. It is found that the functional groups of a GON are more crucial in providing a high electrochemical activity than are the plane edges, and the size of a GON is also a key factor to influence the chemical activity. GONs with smaller sheet sizes but similar functional groups show a weaker electrochemical activity than those with larger sizes. In addition, GONs possess a high activity towards H₂O₂detection and hence are promising for use as an electrode of biosensors.

Supported carbon nanotubes on SiO₂ spheres as robust monolithic catalysts for the oxidative dehydrogenation of ethylbenzene

YUAN 　Hua, 　Liu-Hong-Yang, 　Diao-Jiang-Yong, 　Gu-Xian-Mo, 　Su-Dang-Sheng

2013, 28(5): 336-341. doi: 10.1016/S1872-5805(13)60086-4

Abstract(940)

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Abstract:
Novel carbon nanotube (CNT)/SiO₂ monolithic catalysts for the oxidative dehydrogenation of ethylbenzene to styrene were synthesized by immobilizing CNTs onto commercial SiO₂ spheres. The CNTs completely cover the surface of the SiO₂ spheres, and the catalysts exhibit an improved performance with a higher styrene yield and selectivity, and a higher ethylbenzene conversionthan commercial CNT powder. The catalysts also have a high mechanical strength and a diameter of 4 mm, which can decrease the pressure drop in the fixed bed reactor and also decrease the mass transfer resistance compared with a commercial CNT powder.

Glucose oxidase biosensors based on carbon nanotube non-woven fabrics

SHU 　Lu, 　Deng-　Chen, 　Chen-　Beng, 　Liu-Xiu-Dong, 　Qi-Gong-Bei, 　Yu-Yang-Hai, 　Shu-Meng-Fu

2013, 28(5): 342-348.

Abstract(1335)

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Abstract:
Glucose oxidase biosensors were fabricated by vacuum-impregnation of a glucose oxidase in a polyvinyl alcohol (PVA) aqueous solution into carbon nanotube non-woven fabrics (CNTFs). The performance of the biosensor was evaluated by an electrochemical method, using the biosensors as working electrode, Pt wire as a counter electrode and Ag/AgCl as a reference electrode. The electrical conductivity of the CNTFs was tested with a four-probe method. Tensile strength was measured by a tensile tester. Results show that the response currents of the biosensors increase linearly with the glucose content in aqueous solutions. The linear range is from 2.5 to 30 mmol/L, the detection limit is 2.5 mmol/L and the response time is about 10 s. An acid treatment of the CNTF with 65% HNO3 can increase the response current.

Effect of porosity on the electrical resistivity of carbon materials

SUN Tian-Ming-1, 　Dong-Li-Min-2, 　Wang-　Chen-2, 　Guo-Wen-Li-2, 　Wang-　Chi-1, 　Liang-Tong-Xiang-1

2013, 28(5): 349-354. doi: 10.1016/S1872-5805(13)60087-6

Abstract(1355)

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Abstract:
A model describing the effect of true density and porosity on the electrical resistivity of carbon materials is developed based on ideal fluid mechanics. The modeling results are in good agreement with experimental data with a largest deviation of 2%. Open porosity has a greater effect on resistivity than closed porosity. An increase of open porosity by 40% leads to a resistivity increase by 250% while the same increase in closed porosity gives rise to a resistivity increase of only 25%. The influence of true density on electrical resistivity is not significant.

Preparation of a high performance carbon/carbon composite throat insert woven with axial carbon rods

HOU 　Xiao, 　Cheng-　Wen, 　Chen-　Ni, 　Zhou-Gong-Yang

2013, 28(5): 355-362. doi: 10.1016/S1872-5805(13)60088-8

Abstract(1358)

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Abstract:
A new kind of C/C composite was made to meet the requirements of the severe conditions suffered by a high performance throat-insert of a solid rocket motorusing a method that includes four steps: preform preparation, pressure impregnation and carbonization, high pressure impregnation and carbonization, and high temperature treatment. The preform was made of soft carbon fiber yarns and rigid carbon fiber/resin rods, in which the carbon rods were distributed in an hexagonal arrangement parallel to the axial direction and carbon fiber yarns were laid in a plane perpendicular to the axial carbon rods with a nearest inter yarn angle of 60o. The influence of the main processing conditions on the key properties of these composites was investigated. It is found that the composites have excellent mechanical and thermal properties, and their ablation rates are equivalent to those of C/C composites reinforced with an integral felt preform and 60% lower than those of the C/C composites woven with radial carbon rods.

Rice husk-based activated carbons with high mesoporosity prepared by a combination of CO₂activation and boiling in an alkaline solution

LI Da-Wei, 　Shu-Ti-Feng

2013, 28(5): 363-368.

Abstract(1048)

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Abstract:
A combination of CO₂activation and boiling in an alkaline solution was used to prepare highly mesoporous rice husk-based activated carbons. An orthogonal experimental design was used to investigate the effects of CO₂flow rate, CO₂activation time, NaOH concentration, boiling time and liquid/solid ratioon the porosity of the activated carbons. Results show that an activated carbon with a high mesopore volume of 79% can be obtained under optimized conditions with no need for high temperature treatment with NaOH. The specific surface area, pore volume and yield of the activated carbon can reach 899 m²·g^-1, 0.783 cm³·g^-1 and 26.2%, respectively.

Defect formation and prevention during the preparation of supported carbon membranes

Mohammad Mahdyarfar1, 2, 　Toraj Mohammadi1, 　Ali Mohajeri2

2013, 28(5): 369-377. doi: 10.1016/S1872-5805(13)60089-X

Abstract(1026)

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Abstract:
Supported carbon membranes were prepared using phenolic resin as the carbon precursor and porous graphite as the support. The support was impregnated with the resin solution, dried, cured and carbonized to obtain a membrane layer. One-time coating cannot effectively reduce the number of defects in the membrane. Repeated impregnation cycles to add more carbon layers, using a slow cooling rate during carbonization, performing carbonization at a low temperature and short time (500℃ and 10 min), and coating the supported membranes with permeable polymers were used simultaneously to reduce the population of defects to a certain extent. As a result, gas separation selectivity of the membranes was significantly increased

A comparative study of TiO₂-C hybrid aerogels from TiCl₄ or Ti(OBu)₄ for photocatalytic methylene blue degradation

SHAO 　Xia-1, 2, 　Liu-Wen-Cong-1, 　Zhang-　Rui-2, 　Bo-　Feng-2

2013, 28(5): 378-384.

Abstract(1328)

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Abstract:
TiO₂-C hybrid aerogels were obtained by a one-pot sol-gel method, followed by supercritical drying and pyrolysis, using resorcinol (R) and furfural(F) as carbon sources, and TiCl₄or Ti(OBu)₄ as the TiO₂ precursor. The hybrid aerogels were characterized by XRD, HR-TEM and N₂ adsorption. The photocatalytic activity of the samples was evaluated based on the conversion of methylene blue (MB) under UV light. Results showed that the type of precursor and the mass ratio of TiO₂ to carbon influenced the surface area and MB conversion. The TiO₂-C hybrid aerogels using TiCl₄ as TiO₂ precursor had a higher surface area and a better photocatalytic activity than those using Ti(OBu)₄ as precursor under otherwise identical conditions. The best sample was obtained when TiCl₄ was used and the TiO₂ content was 40%. This had the largest average pore size of 7.8 nm, the highest mesopore volume of 0.40 cm³/g and the highest MB conversion of 99.6% under an ultraviolet exposure for 180 min.

Oxidative modification of natural graphite for use as the anode of a lithium ion battery

DIAO 　Zhuo, 　Gu-Xiao-Chuan, 　Li-　Jing, 　Li-Xiu-Beng, 　Zhang-　Wan, 　Wang-　Hua

2013, 28(5): 385-390.

Abstract(979)

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Abstract:
Natural graphite was modified by oxidation with a mixture of sulfuric acid (98%) and hydrogen peroxide (30%) with a volume ratio of 1∶1, followed by a heat treatment under argon at 900 ℃ for 3 h to overcome its disadvantages of the presence of active surface groups and volume changes produced by the intercalation/deintercalation of Li ions. Results showed that the graphitic layers of the expanded graphite were exfoliated and grain size increased from 26.8 to 35.2 nm after the modification. Constant current charging-discharging and cyclic voltammetry indicated that its high rate performance and cyclic stability were improved. The capacity retention ratio increased from 45.7% for the natural graphite to 81.3% for the modified one in the 50th cycle.

Effect of molecular weight and the molecular weight distribution of a condensed polynuclear aromatic resin on the constituents and properties of their pyrolysis products

ZHANG Jin-Cai-1, 3, 　Shi-Jing-Li-1, 4, 　Diao-　Yun-1, 2, 　Guo-Quan-Gui-1, 　Liu-　Lang-1

2013, 28(5): 391-398.

Abstract(1053)

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Abstract:
Three condensed polynuclear aromatic resins with different molecular weights (Mws) and Mw distributions were heated at 900, 1500, 2200, 2600 and 3000℃ for 2h. The resulting carbons were characterized by XRD, helium pycnometry and a powder electrical resistance test. The graphitic, amorphous and turbostratic constituents in the carbons were obtained from XRD. Results showed that both the Mw and the Mw distribution in the resins played important roles in the properties and constituents of the carbons produced from them. The larger the Mw and the narrower the Mw distribution, the higher the graphitic content in the carbons produced at 3000℃. The larger the Mw and the wider the Mw distribution, the higher the apparent density of the carbons produced at the same pyrolysis temperature. The effect of Mw on the powder resistance of the carbons is negligible.

A brief overview on the 11th National Symposium on New Carbon Materials

SONG 　Yan1, 　Liu-Jia-Bin2, 　Liu-Yan-Zhen2

2013, 28(5): 399-400.

Abstract(1056)

PDF(1021)

Abstract:
The 11^th National Symposium on New Carbon Materials was held in Taiyuan, Shanxi, P. R. China, hosted by the Institute of Coal Chemistry, Chinese Academy of Sciences, during Aug. 16-20, 2013. About 300 attendees participated in the conference, and 142 papers were accepted for discussion, including plenary lectures, keynotes talks, oral presentations and poster presentations. The papers were classified into the following seven topics: carbon fibers and their composites, carbon-based composites, nanostructured carbons, porous carbons, intercalated and modified carbons，carbon materials for energy storage, carbon materials for health and environment protection. Research and development of carbon fibers and their composites, carbon-based composites, and porous carbons are quite active. Rapid progress has also been made on the energy storage applications of carbon materials and nanocarbons.

2013 Vol. 28, No. 5

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