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Volume 1993 (1993)
- Issue 160 Pages 247-
- Issue 159 Pages 177-
- Issue 158 Pages 141-
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Volume 1993, Issue 160
Displaying 1-8 of 8 articles from this issue
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Preparation of Charcoals from Cryptomeria and Chamaecyparis and Their PropertiesMitsunori Hitomi, Yoshiya Kera, Hideki Tatsumoto, Ikuo Abe, Isao Kawaf ...1993 Volume 1993 Issue 160 Pages 247-254
Published: December 28, 1993
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSCharcoals as adsorbent were prepared by carbonizing Cryptomeria and Chamaecyparis at various temperature. The adsorptive properties of the charcoals in the gas and liquid phases were investigated and the following results were obtained.
(1) The adsorption capacity of the charcoals in the gas and liquid phases increased with an increase in carbonization temperature. The optimum temperature for preparation of adsorbent was 900°C.
(2) The specific surface area of the charcoal prepared by carbonizing Chamaecyparis at 900°C. was 641m2/g and the value was about double of that of commercial charcoals and was 60-70% of commercial activated carbons.
(3) The charcoals prepared at low temperature possessed a high adsorbability for base and the charcoals prepared at high temperature possessed a high adsorbability for acid. The charcoals prepared at 400°C were applicable to the deodorization of ammonia gas.
(4) The charcoal prepared by carbonizing Chamaecyparis at 900°C had an high adsorbability for phenol of very low concentration because the mean pore diameter was very small.View full abstractDownload PDF (978K) -
Takashi Kyotani, Ken-ya Suzuki, Hiromi Yamashita, Akira Tomita1993 Volume 1993 Issue 160 Pages 255-265
Published: December 28, 1993
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSAn attempt was made to prepare carbon-metal composites by the heat treatment of graphite oxide (GO) which was ion-exchanged with metal cations. The composites thus obtained were characterized to elucidate the dispersion state and the chemical form of metal species in carbon matrix. It was found that metal species are still dispersed at atomic level in the matrix of the samples prepared at 500°C and some aggregation of metal species takes place at 800°C. Furthermore, Fe-containing carbon composites showed magnetic anisotropy, which originates from spatial anisotropy of Fe species in carbon matrix. Since GO can be ion-exchanged with a variety of metal cations, this method offers a new route for preparing a variety of carbon-metal composites with anisotropic properties.View full abstractDownload PDF (4401K) -
Shigeaki Suganuma, Tetsuya Mizu, Haruo Sakagoshi, Kunitaka Momota, Fuj ...1993 Volume 1993 Issue 160 Pages 266-271
Published: December 28, 1993
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSFluorine intercalated graphite compounds CxF with ionic or semi-ionic C-F bonding were prepared by direct fluorination of HOPG at 0°C or room temperature, and impedance measurements of these materials were carried out. Electrochemical intercalation and deintercalation of fluoride ions into graphite and from CxF, respectively, were investigated using cetonitrile solutions containing tetramethyl ammonium fluoride salts. The results indicate that the fluoride ions in the graphite gallery have some mobility, and the electrochemical intercalation and deintercalation of fluoride ions are effected by applied potential gradient. These results suggest that CxF are fluoride ion conducting solid state electrolytes.View full abstractDownload PDF (698K) -
Yoshiaki Matsuo, Tsuyoshi Nakajima, Muneyuki Motoyama1993 Volume 1993 Issue 160 Pages 272-278
Published: December 28, 1993
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSFluorine-graphite intercalation compound (CxF) has been synthesized from HOPG by electrochemical method using solid electrolyte PbSnF4 in a fluorine atmosphere. The compositions of the obtained CxF samples were between stage 7+4, C16.5F and stage 1, C2.4F. Fluorination was highly promoted by charging and, the fluorine content in the sample increased with increase of the charge. Two types of stage 1 bi-intecalation phases, and the in-plane superlattice with a0=2ag and b0=√3ag were observed for stage 1, C2.4F, for which the c-axis and in-plane structure models have been proposed. The calculated intensity of X-ray diffraction lines is in good agreement with observed one.View full abstractDownload PDF (907K) -
Kazuyoshi Kuriyama1993 Volume 1993 Issue 160 Pages 279-282
Published: December 28, 1993
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSActivated carbon fibers have nano-space that contributes to their huge specific surface area (SSA) of more than 1000m2/g. The SSA shows a critical decrease at HTT-1600°C, with an almost constant value of SSA up to this HTT, although the basicstructure is conserved up to HTT=2000°C. For the mechanism of this sudden decrease in SSA, two ideas based on a molecular sieve effect in the crystallite intra-space and a percolation of crystallites are discussed.View full abstractDownload PDF (502K) -
Katumi Kaneko1993 Volume 1993 Issue 160 Pages 283-289
Published: December 28, 1993
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe interaction potentials from the opposite micropore walls are overlapped to produce nanospaces having enhanced potential energy. Such carbon nanospaces are characterized by N2 adsoption at 77K and He adsorption at 4.2K. In particular, He adsorption method is quite effective for access of smaller nanospaces. Small angle X-ray scattering leads to three dimensional geometry of the carbon nanospace. The supercritical NO gas can be abundantly stored in the carbon nanospace in the form of the dimer. The concentrated NO dimer in the nanospace changes to N2O in the presence of SO2. SO2 molecules form an ordered structure in the nanospace.View full abstractDownload PDF (945K) -
Katsumi Yoshino1993 Volume 1993 Issue 160 Pages 290-300
Published: December 28, 1993
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSFullerenes such as C60, C70 and so on can be doped in conducting polymers such as poly (3-alkylthiophene) and poly (2, 5-dialkoxyphenylene vinylene) whose main chains are composed of highly extended conjugated electron systems. The doping effect depends on the electronic band schemes of both conducting polymer and fullerene. In the conducting polymer whose valence band top is high in energy, fullerene is effectively doped just as conventional dopants (acceptors). On the other hand, in the conducting polymer whose valence band top is low in energy, fullerens are not effective dopants under dark but various interesting phenomena have been observed upon light irradiation due to photo-induced charge transfer between conducting polymer and fullerene. Junctions made of conducting polymer and fullerene layers also exhibit unique characteristics.
Various other novel properties in conducting polymer-fullerene composite are also discussed.View full abstractDownload PDF (1329K) -
Yoichi Takahashi1993 Volume 1993 Issue 160 Pages 301-311
Published: December 28, 1993
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIntercalation of organic molecules into alkali metal (AM)-graphite intercalation compounds (GIC) and their secondary reactions, such as oligomerization, in the interlayer space are reviewed.
Some aromatic molecules such as benzene and tetrahydrofuran (THF) have been known to be intercalated to AM-GICs, resulting ternary GICs. It has been proven that benzene molecules intercalated in the GICs oligomerize slowly in the interlayer nanospace, probably under the catalytic effect of Cs+ ion.
On the other hand, aliphatic hydrocarbons have been known to be physintercalated to stage 2 AM-GICs, in particular CsC24. Among aliphatic hydrocarbons, ethylene and acethylene, which have a double or triple bond, showed unusual behavior: Contrary to usual physintercalation, the temary GICs of C2H4 and C2H2 with CsC24 were found to be very stable even in air. Further investigations on the C2H4 temary GIC, by using XRD, chemical analysis/MS, calorimetry etc., have revealed that the observed unusual stability is caused by the oligomerization of C2H4 molecules in the interlayer nanospace. In contrast to other organic molecule-temary GICs, the intercalation of C2H4 molecules into CsC24 gives very little effect in its electrical conductivity, indicating that the backdonation of conduction electrons from graphene layers isrelatively small.
The possible secondary reaction of intercalated molecules, in particular oligomerization or polymerization, will give a vast prospects in obtaining new functional GICs with high electrical conductivity and stability.View full abstractDownload PDF (1423K)
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