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Volume 2013 (2013)
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Volume 2013, Issue 258
Displaying 1-12 of 12 articles from this issue
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Review Papers
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Masayuki KawaguchiArticle type: Review Paper
2013 Volume 2013 Issue 258 Pages 165-170
Published: June 15, 2013
Released on J-STAGE: July 15, 2013
JOURNAL RESTRICTED ACCESSCarbonaceous materials of the boron/carbon/nitrogen (B/C/N) system and carbon/nitrogen (C/N) system have been reviewed. A material with a composition BC2N made by CVD had the graphite-like layer structure. Sodium was intercalated into and de-intercalated out of BC2N by an electrochemical method, and the material can be used as an anode of sodium ion batteries. Magnesium was intercalated into BC2N by vapor phase reaction. The intercalations can be explained by a relation between the ionization potentials of metals and electron affinities of the host materials. C/N materials have a high hardness, are photoluminescent and exhibit reversible ion adsorption/desorption in solution. These properties depend on composition, chemical bonding and structure, and should be useful in wide fields.View full abstractDownload PDF (824K) -
Masaya KodamaArticle type: Review Paper
2013 Volume 2013 Issue 258 Pages 171-178
Published: June 15, 2013
Released on J-STAGE: July 15, 2013
JOURNAL RESTRICTED ACCESSNovel nitrogen-enriched carbon materials prepared from heterocyclic hydrocarbons containing nitrogen atoms by an ordinary heat treatment method are reviewed. On account of the nitrogen atoms in the starting hydrocarbons, a certain amount (5-45 wt%) of nitrogen remained in the resulting carbons. In addition, thin film, layered, mesoporous and fibrous structures were successfully introduced into the nitrogen-enriched carbon body using selective precursors and the template method. The obtained carbons exhibited a unique electrochemical capacitor performance such as high specific capacitance and do not appear to follow the normal relationship between electrolyte ions and pore structure on an electrode surface. These features can be attributed to the electrochemical interaction of nitrogen in the carbon network with electrolyte ions. Although some inexplicable anomalies remain, these nitrogen-enriched carbon materials have high promise as an electrochemical capacitor electrode material.View full abstractDownload PDF (2027K) -
Kazuyuki TakaiArticle type: Review Paper
2013 Volume 2013 Issue 258 Pages 179-186
Published: June 15, 2013
Released on J-STAGE: July 15, 2013
JOURNAL RESTRICTED ACCESSGraphene as a fundamental building block for carbon materials has attracted great attention over the last decade because of its novel properties. The peculiar electronic properties of graphene intrinsically originate from the geometry of its honeycomb lattice. In addition, the pure two-dimensional structure, where all carbon atoms lie in the surface, gives graphene extreme sensitivity to the influence of external chemical species, where the electronic properties are easily tuned through chemical modification. In this review, the electronic properties of graphene are discussed in terms of the influence of the topological and chemical modification. This promises to be a promising strategy to understand the fundamental properties of carbon materials in various forms.View full abstractDownload PDF (1425K)
Research Papers
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Yutaka Kaburagi, Miu Ohoyama, Emi Shindo, Akira Yoshida, Norio Iwashit ...Article type: Research Paper
2013 Volume 2013 Issue 258 Pages 187-194
Published: June 15, 2013
Released on J-STAGE: July 15, 2013
JOURNAL FREE ACCESSCommercially available pure cellulose paste of plant origin composed of nanofibrils was dispersed in ethanol or distilled water, and sheets made of the nanofibrils were prepared by filtration. The sheets were carbonized and then heat-treated at temperatures between 2400 and 3200 °C at atmospheric pressure, and the original paste was also carbonized and heat-treated at 3100 °C. The diameter of the cellulose nanofibrils was found to be 30-300 nm in the sheets, while no fibrous texture was observed in the original paste. Structural order of the carbonized sheets improved with increasing heat treatment temperature, and was especially remarkable for the sheet derived from nanofibrils dispersed in ethanol, though turbostratic components were observed even for the sheet heat-treated at 3200 °C. On the other hand, the 3100 °C-treated paste exhibited a typical turbostratic structure. The development of graphite structure in the carbon sheets is probably attributed to surface graphitization, the same as the graphitization of the carbonized sheets prepared from bacteria cellulose nanofibers by heat treatment at high temperatures reported previously. The structural development of the present heat-treated sheets was less than that of the heat-treated sheets prepared from bacteria cellulose nanofibers. The result could be attributed to the thicker diameters and lower crystallinity of the present precursor nanofibrils compared to those of the bacteria cellulose nanofibers.View full abstractDownload PDF (2850K) -
Sei-ichi Taira, Shotaro Yamamoto, Natsuko Kojima, Hirofumi Kanoh, Tomo ...Article type: Research Paper
2013 Volume 2013 Issue 258 Pages 195-200
Published: June 15, 2013
Released on J-STAGE: July 15, 2013
JOURNAL FREE ACCESSWater vapor adsorption on porous carbons has been actively studied because of its importance in various applications and basic science. However, the unique behavior and structure of water in carbon nanospaces have still been remained unclear. Carbon nanotubes inherently have rather restricted one-dimensional nanospaces and thus, force the adsorbed water to be aligned in them. The structure of water adsorbed in those nanospaces is ice-like even at ambient temperature. In this paper, we show the water structures in two-different single wall carbon nanotubes (CNTs) with average CNT diameters of 1.1 (narrow) and 2.5 (wide) nm at 260-300 K, which were evaluated by using in situ synchrotron X-ray diffraction (XRD). The water structures in the both CNTs were nano-ice-like forms at 300 K rather than a liquid-like. The ice-like structure in the wide CNTs was developed with decreasing temperature, although even at 260 K, sharp ice peaks were not observed in the XRD pattern. On the other hand, in the narrow CNTs, the water structure was gradually transformed from an ice-like form to a liquid-like form with decreasing temperature to 260 K. The structure transformation of solid-to-liquid with decreasing temperature is due to the fact that the highly restricted nanospaces obstruct the formation of ice-like clusters and/or hydrogen bonds. The anomalous structure transformation in both CNTs could be a clue to reveal one-dimensional water behavior in CNTs.View full abstractDownload PDF (1076K)
Review Papers
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Satoshi Matsushita, Mutsumasa Kyotani, Kazuo AkagiArticle type: Review Paper
2013 Volume 2013 Issue 258 Pages 201-209
Published: June 15, 2013
Released on J-STAGE: July 15, 2013
JOURNAL RESTRICTED ACCESSOne-handed helical graphite films with a structure controlled by that of the original iodine-doped helical polyacetylene (H-PA) films were prepared using the recently developed morphology-retaining carbonization method. The fibrillar structure of the H-PA film remains unchanged even after carbonization at 800 °C. The weight loss of the film due to carbonization was very small; only 10-29% of the weight of the film before doping was lost. Furthermore, the graphite film prepared by subsequent heating at 2600 °C retained the same structure as that of the precursor films. The screw direction, degree of twist, and vertical or horizontal alignment of the helical graphite film were well controlled by changing the sense and pitch of the helix, and the orientation of the chiral nematic liquid crystal (N*-LC) used as an asymmetric LC reaction field. The important potential of these graphite films is exemplified in their electrical properties. The horizontally aligned helical graphite film exhibits an increase in electrical conductivity compared to the nonaligned one. The aligned helical graphite film also shows an electrical anisotropy in which conductivity parallel to the helical axis of the fibril bundle is higher than that perpendicular to the axis.View full abstractDownload PDF (11538K) -
Yutaka TakaguchiArticle type: Review Paper
2013 Volume 2013 Issue 258 Pages 210-215
Published: June 15, 2013
Released on J-STAGE: July 15, 2013
JOURNAL RESTRICTED ACCESSA water-soluble supramolecular nanohybrids was obtained by sonication and centrifugation of a water dispersion of fullerodendron and single-walled carbon nanotubes (SWCNTs). A coaxial nanocable structure was confirmed by photoluminescence spectra, AFM, and TEM, that showed a SWCNT core and fullerodendron shell. Surface functional groups of the hybrid can interact to form compounds with various inorganic materials such as CaCO3 and SiO2. SWCNT/fullerodendron/CaCO3 fabricated through biomimetic mineralization showed unique core-shell microsphere structures while SWCNT/fullerodendron/SiO2 still had a coaxial nanocable structure. Because of a photofunctional interface, SWCNT/fullerodendron/SiO2 hybrids have a high photocatalytic activity (ϕ=0.31) for the evolution of hydrogen from water under irradiation with visible light (450 nm). A single component photocatalytic system was constructed by introducing Pt complexes into SWCNT/fullerodendron supramolecular nanocomposite.View full abstractDownload PDF (2726K)
Series Lecture
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Yutaka KaburagiArticle type: Series Lecture
2013 Volume 2013 Issue 258 Pages 216-229
Published: June 15, 2013
Released on J-STAGE: July 15, 2013
JOURNAL RESTRICTED ACCESSDownload PDF (3263K)
Recent Doctoral Theses
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Saya TakeuchiArticle type: Recent Doctoral Thesis
2013 Volume 2013 Issue 258 Pages 230-231
Published: June 15, 2013
Released on J-STAGE: July 15, 2013
JOURNAL RESTRICTED ACCESSFundamental studies for a calcium ion battery and improvement of electrolytes for conventional lithium ion batteries by controlling the solvation structure of lithium ions were studied. In chapter 1, electrochemical behavior of graphite electrodes in organic solvents containing calcium salts was studied. The study showed that co-intercalation of calcium ions and solvent molecules took place in electrolytes used in the study, and showed the importance of de-solvation of calcium ion to realize a calcium ion battery. Furthermore, it was suggested that surface film control is critical for intercalation of calcium ions into graphite electrodes. Chapters 2-7 aim to improve electrolyte for conventional lithium ion battery in terms of low-temperature performance and non-flammability. Ethylene carbonate (EC) is used as a main organic solvent for lithium ion batteries, but has problems on ionic conductivity at low temperature and flammability. Propylene carbonate (PC) has advantage in low-temperature ionic conductivity, and trimethyl phosphate (TMP) has advantage in non-flammability, but those solvents are not compatible with graphite electrode because of exfoliation and degradation of graphite, respectively. In this thesis, it was made clear that intercalation of lithium ions can take place by controlling solvation structure of lithium ions by adding stronger Lewis acid, such as calcium ions, into PC-based electrolyte. Successful electrochemical intercalation of lithium ions in PC-based electrolytes is attributed to effect of calcium ions on the solvation structure of lithium ions. The similar effect of calcium ion addition on lithium ion intercalation was also observed in electrolytes containing TMP. The work also shows that co-solvents, such as dimethyl carbonate (DMC), can also affect intercalation reaction of lithium ions. Hence, lithium ion intercalation can take place by controlling both amount of calcium ion and co-solvent. The above approach for lithium ion intercalation enables to use organic solvents that were considered not to be used for lithium ion batteries, and opened for more options for solvents to improve performance of the batteries.View full abstractDownload PDF (296K) -
Shiori KuboArticle type: Recent Doctoral Thesis
2013 Volume 2013 Issue 258 Pages 232-233
Published: June 15, 2013
Released on J-STAGE: July 15, 2013
JOURNAL RESTRICTED ACCESSThis thesis presents the production of nanostructured carbonaceous materials via a combined hydrothermal carbonisation (HTC)– nanocasting technique with the particular focus on the generation of well-defined pore structures/geometries. Firstly, inorganic sacrificial templates such as anodic alumina membranes and mesoporous silicas are used as hard templates to yield tubular carbons and mesoporous carbonaceous spheres, whilst, importantly, their surfaces are decorated with tuneable oxygenated surface functionalities. Secondly, complementary to this so called “hard templating” approach, a combined HTC–soft templating route for the direct synthesis of ordered porous carbonaceous materials is demonstrated. The use of PEO-PPO-PEO triblock copolymer as a soft template allows the successful production of single crystal–like carbonaceous particles with Im3m pore symmetry, whilst d-fructose represents a useful carbon precursor as the HTC process can be performed at a reduced temperature of 130 °C, thus allowing access to stable micellular phase. Throughout the thesis, the materials are characterised carefully mainly by electron microscopy, small/wide-angle X-ray scattering, N2/CO2 gas sorption and FTIR and Raman spectroscopy. The presented synthetic routes provide access to nanostructured carbonaceous materials with rich surface chemistry through a low-temperature, aqueous procedure using inexpensive and renewable carbon precursors. The obtained materials are of potential interest as candidates in chromatography, electrochemistry or drug delivery. In the following section, summary of each chapter in the thesis is presented.View full abstractDownload PDF (248K) -
Genki OdaharaArticle type: Recent Doctoral Thesis
2013 Volume 2013 Issue 258 Pages 234-239
Published: June 15, 2013
Released on J-STAGE: July 15, 2013
JOURNAL RESTRICTED ACCESSThis thesis shows for the first time in-situ observation of macroscopic, high quality graphene growth on metal surfaces through surface segregation by controlling the substrate flatness and temperature. This indicates that the new technology of graphene growth was developed, which corresponds to the growth of kish graphite (one of the highest quality in the artificial graphite crystals). In particular, it is very important for this study to have shown the possibility of growing expansive single-domain graphene sheets even on a polycrystalline metal surface. These results could contribute greatly to the practical application of graphene or related materials.View full abstractDownload PDF (348K)
TANSO Salon
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Eiji OsawaArticle type: TANSO Salon
2013 Volume 2013 Issue 258 Pages 236-239
Published: June 15, 2013
Released on J-STAGE: July 15, 2013
JOURNAL RESTRICTED ACCESSDownload PDF (469K)
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