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Sugita, Tsuyoshi; Yoshida, Hirokazu*; Kodama, Hiroto*; Ishigaki, Toru*; Oba, Yojiro*
Journal of the Ceramic Society of Japan, 132(9), p.548 - 554, 2024/09
Times Cited Count:1 Percentile:59.54(Materials Science, Ceramics)Porosity plays an essential role in the performance of ceramics. In this study, the effects of clay composition and firing temperature on the pore size distribution of ceramics were evaluated by small-angle neutron scattering (SANS) measurements. Compared with quartz-rich pure Kasama clay, a mullite-rich Kasama clay blend had smaller pores after heat treatment. SANS measurements of DO-absorbed samples revealed that open pores with sizes ranging from tens of nanometers to about a micrometer contributed to the absorption of water. The closed and open pores coarsened and the total porosity decreased with increasing firing temperature.
Yamaguchi, Daisuke; Koizumi, Satoshi; Hasegawa, Yoshio*; Hishinuma, Yukio*; Suzuki, Masashi*; Kodama, Hiroto*; Onuma, Masato*; Oba, Yojiro*
no journal, ,
Among the wide variety of photo-catalytic products titanium dioxide (TiO)) is one of the most promising material and various improvement has been attempted. Recently it has been confirmed that the nitrogen (N)-doped TiO
can be activated not only by ultraviolet light but also by visible light and thereby an enhancement of the efficiency is attained. However, the difference in structure between bare TiO
and N-doped one has not yet been fully clarified despite the considerable structural analyses by using X-ray diffraction (XRD) or microscopy. In this study the structure of N-doped TiO
was studied by small-angle neutron (SANS) and X-ray scattering (SAXS) methods by profiting the considerable difference of the scattering contrast of N atom to the neutron and to the X-ray. The resultant SANS and SAXS profiles are different between them, especially at high q region of (q
1(nm
), where q denotes the magnitude of scattering vector. This result can be interpreted as the localization of N atoms at around the surface area.
Yamaguchi, Daisuke; Noda, Yohei; Koizumi, Satoshi; Hasegawa, Yoshio*; Hishinuma, Yukio*; Suzuki, Masashi*; Kodama, Hiroto*; Onuma, Masato*; Oba, Yojiro*
no journal, ,
The structure of nitrogen (N)-doped titanium dioxide (TiO), which is a visible light photocatalyst, was investigated by small-angle neutron (SANS) and X-ray scattering (SAXS) methods. The bare TiO
was fabricated by sol-gel method and possessed a characteristic length of ca. 10 nm due to some regularity consisting of TiO
particles and pores. In the air, bare TiO
and N-doped TiO
specimens showed a similar scattering profiles each other for both of SANS and SAXS measurements. A slight increase of scattering intensity was observed for N-doped TiO
specimen only on the SANS profile. To confirm whether the slight difference in SANS profiles between bare TiO2
and N-doped TiO
specimens was due to the doped N atoms, both of bare TiO
and N-doped TiO
specimens were soaked in the mixture of H
O/D
O = 55/45 (w/w) mixture, of which scattering contrast for neutron is the same as TiO
, and measured by SANS. The resultant SANS profiles of soaked bare TiO
and N-doped TiO
specimens were distinctly different each other and the scattering from doped N atoms, which gives the information of their distribution was captured.
Yamaguchi, Daisuke; Hasegawa, Yoshio*; Hishinuma, Yukio*; Suzuki, Masashi*; Kodama, Hiroto*; Koizumi, Satoshi*; Noda, Yohei; Oba, Yojiro*
no journal, ,
Anion, e.g., nitrogen (N) doped titanium dioxide (TiO), being expected to exhibit an improved photo-catalytic property due to the effect of narrowing in the band gap, was investigated by small- (SANS) and wide-angle neutron scattering. Among wide variety of photo-catalytic products, TiO
is one of the most promising and various improvements have been done. However, the difference in structure between bare TiO
and N-doped TiO
has not yet definitively clarified despite the considerable structural analyses by X-ray diffraction or X-ray photoemission spectroscopy. With profiting from an enhanced scattering length of N atoms to the neutron beam, an attempt to capture the distribution of N atoms in N-doped TiO
by SANS was conducted. Specimens prepared with and without N-doping were compared. The traces of doped N species on the scattering profiles might be brought out from invisible differences with contrast variation method employing the soakage in tuned H
O/D
O mixture possessing nearly the same scattering length density as TiO
component.
Yamaguchi, Daisuke; Hasegawa, Yoshio*; Hishinuma, Yukio*; Kodama, Hiroto*; Suzuki, Masashi*; Koizumi, Satoshi*; Noda, Yohei; Oba, Yojiro*
no journal, ,
Anion doped titanium dioxide (TiO), which is expected to exhibit an improved photo-catalytic property due to the effect of narrowing in the band gap, was investigated by small-angle neutron scattering (SANS). Among wide variety of photo-catalytic products, TiO
is one of the most promising and various improvements have been done. On the functional aspect it has been confirmed that for instance, nitrogen (N) doped TiO
can be activated not only by the photons of which wavelength is corresponding to ultraviolet but also by those of visible light and thereby an enhancement of the efficiency is attained. However, the difference in structure between bare TiO
and N-doped TiO
has not yet definitively clarified despite the considerable structural analyses by using X-ray probes. With profiting from an enhanced scattering length of N atoms to the neutron beam, an attempt to capture the distribution of N atoms in the N-doped TiO
by SANS is presented here.
Yamaguchi, Daisuke; Koizumi, Satoshi; Hasegawa, Yoshio*; Hishinuma, Yukio*; Suzuki, Masashi*; Kodama, Hiroto*; Onuma, Masato*; Oba, Yojiro*
no journal, ,
The structure of nitrogen (N)-doped titanium dioxide (TiO), which exhibits an improved photo-catalytic property, was investigated by small-angle neutron (SANS) and X-ray scattering (SAXS) methods. The N-doped TiO
nanosheet showed a SANS profile, of which q-dependence is nearly identical to that of undoped TiO
nanosheet, however, of which intensity is three times as large as that of undoped TiO
nanosheet. As for the SAXS measurements, hardly any difference was observed between undoped TiO
nanosheet and N-doped one. For N-doped nanosheet, a core-shell structure where TiO
particles locate at the center and N atoms surround the surface of TiO
particles was deduced from the analysis of those obtained SANS and SAXS profiles by taking account of the difference in scattering contrast between neutron and X-ray for each component, i.e., Ti, O, and N atoms.
Yamaguchi, Daisuke; Koizumi, Satoshi; Hasegawa, Yoshio*; Hishinuma, Yukio*; Suzuki, Masashi*; Kodama, Hiroto*; Onuma, Masato*; Oba, Yojiro*
no journal, ,
From the combined SANS and SAXS profiles, both of the neat and N-doped TiO catalyst was characterized to have a sheet-like shape with thickness of several tens to hundreds of nm and to be composed of sub-unit TiO
particles of several nm. On the SANS profile, the N-doped TiO
catalyst showed a q-dependence nearly identical to that of neat TiO
catalyst, however, of which intensity is three times as large as that of neat TiO
catalyst. On the other hand, by SAXS measurement, hardly any difference was observed between neat TiO
catalyst and N-doped one. The analysis of those obtained SANS and SAXS profiles suggests that the localization of doped N atoms at the surface of TiO
particles and hence TiO
-core/N-shell structure can be inferred for the N-doped TiO
material.
Yamaguchi, Daisuke; Noda, Yohei; Koizumi, Satoshi; Hasegawa, Yoshio*; Hishinuma, Yukio*; Suzuki, Masashi*; Kodama, Hiroto*; Onuma, Masato*; Oba, Yojiro*; Yuasa, Takeshi*; et al.
no journal, ,
Nowadays industrial materials tend to include a variety of additives and to be a composite of them to satisfy a high request for intelligent function and durability. Elucidation of such a multi-component and hierarchical structure is really a tough work but indispensable to learn the fundamentals of relation between the structure and property and to attain a reasonable improvement of those materials. Combined use of small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS) often gives a good clue to decompose the total scattering of the organic/inorganic composite into the partial scattering from a particular component. Two examples will be demonstrated here for extracting the structural information from the composite specimen via this method; one is the distribution of the dopant nitrogen atoms in the porous photocatalyst and the other is the dispersion state of fillers in the rubber matrix.
Yamaguchi, Daisuke; Koizumi, Satoshi; Ojima, Hitoshi*; Isoyama, Ryo*; Ishiwatari, Yoshiyuki*; Kodama, Hiroto*; Takeda, Hisanori*; Fukita, Hitoshi*; Takashima, Yoshiyuki*
no journal, ,
Resin-filler composites were investigated by small-angle neutron scattering (SANS). Two types of fillers, talc and TiO, were employed and compounded with polypropylene in this study. The dispersion state of the fillers was examined by SANS measurements. In addition, the size distribution of the fillers was separately measured through the laser right scattering and SEM. The calculated scattering function including the polydispersity of fillers whose size distribution reflects the results of laser right scattering and SEM consistently reproduced the experimental SANS scattering profiles.