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Abstract : Vol.40No.1(2005.3)
Special Issue：Nano-structure
Controls of Functional Powders
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Review
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| P.1 |
Nano-structure
Controls of Functional Powders |
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Recent developments in functional
powders and their fabrication were overviewed with a
focus on their microstructure and material design. We
discuss features of four novel powders studied at Toyota
CRDL: 1) Mono-dispersed super-microporous silica spheres,
2) Fullerene polymer-like materials, C60Pdn
, for toluene adsorption, 3) Single-walled carbon nanotubes,
and 4) Flame-synthesized metal oxides.
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Research Reports
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| P.5 |
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Takao Tani, Kazumasa Takatori,
Sotiris E. Pratsinis
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Pure and mixed ZnO-SiO2 particles were prepared
by flame spray pyrolysis (FSP) of zinc acetate (ZA)
and either hexamethyldisiloxane (HMDSO) or SiO2-sol
dispersed in either methanol or a water-in-oil emulsion.
The product particles were characterized by nitrogen
adsorption, infrared absorption and X-ray diffraction.
The evolution of solid or hollow particle formation
along the flame axis was elucidated by observing particles
collected in the spray flame by thermophoretic sampling.
The effects of using different silicon precursors and
solvents on product particle characteristics were evaluated.
The characteristics of the product particles can be
controlled by the Si precursor and solvent.
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| P.14 |
The
First Application of Fullerene Polymer-like Materials,
C60Pdn , as Gas Adsorbents |
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Akari Hayashi, Satoru Yamamoto,
Kenichirou Suzuki, Takaaki Matsuoka
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C60Pdn
polymer-like materials were prepared and reacted with
toluene, one of the harmful gases. Toluene was successfully
adsorbed on C60Pdn at ambient
temperature without additional energy sources. This
adsorptivity was retained even at low concentration
of 1000 ppb, which is close to the actual toluene concentration
in the environment. The strong adsorption of toluene
molecules toward C60Pdn
was confirmed by IR, TG-IR, and cyclic voltammetry.
The π- electrons of toluene are believed
to adsorb on the partially positive Pd atoms of C60Pdn
, and theoretical studies have suggested that
the π-electrons of C60 and toluene
overlap through the d-electron orbitals of the
Pd atom, representing not just physical adsorption.
This result should open the door to application of fullerene
materials as adsorbents for harmful gases.
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| P.22 |
Control
of Diameter Distribution of Single-walled Carbon Nanotubes
Using the Zeolite-CCVD Method |
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Atsuto Okamoto, Hisanori Shinohara
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Single-walled carbon nanotubes (SWCNTs)
have been synthesized on zeolite powder with Fe/Co catalysts
by catalytic chemical alcohol-vapor deposition (CCAVD).
We first used a cold wall reactor at atmospheric pressure.
The reactor system was then modified: radio-frequency
heating was used for zeolite-CCAVD. The G/D ratio (~25)
obtained is equivalent to that obtained by conventional
CCAVD under reduced pressure. This indicates the high
purity of the present specimen. The diameter distribution
of the synthesized SWCNTs, estimated by analysis of
resonant Raman spectroscopy using excitation wavelengths
at 488, 514.5 and 633 nm, shifts towards larger diameters
with increasing synthesis temperature and decreasing
carbon supply rate (ethanol temperature). We present
a diameter-selective growth model that is based on the
relationship between the carbon supply rate, synthesis
temperature and catalyst size.
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| P.28 |
Synthesis
of Mono-dispersed Spherical Mesoporous Silica
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Kazuhisa Yano
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Mono-dispersed spherical mesoporous
silica was synthesized from tetramethoxysilane and alkyltrimethylammonium
bromide (CnTMABr) with short alkyl-chain
as a surfactant under very specific conditions. Regularity
of mesopores was high when dodecyltrimethylammonium
(C12TMABr) was used. The particle size was
found controllable by changing synthesis temperature,
water/methanol ratio, and silica source while mono-dispersion
characteristics were retained when decyltrimethylammonium
bromide (C10TMABr) was used. The obtained
mono-dispersed spherical mesoporous silica had a particle
size equivalent to the wave length of visible light,
and thus its application to an optical use such as photonic
crystal is expected.
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