2016.04.01

2015.04.01

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1039/D3MA00597F

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DOI： https://doi.org/10.3390/ma17020338

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DOI： https://doi.org/10.2109/jcersj2.23047

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DOI： https://doi.org/10.2109/jcersj2.23026

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DOI： https://doi.org/10.1016/j.ceramint.2023.04.048

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DOI： https://doi.org/10.2109/jcersj2.23007

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DOI： https://doi.org/10.1080/21870764.2023.2173849

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DOI： https://doi.org/10.7566/JPSJ.91.113704

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DOI： https://doi.org/10.1016/j.jes.2021.05.025

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

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DOI： https://doi.org/10.2109/jcersj2.21147

Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：(MISC) Introduction and explanation (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.colsurfa.2020.125664

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DOI： 10.1016/j.jssc.2020.121858

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DOI： 10.2109/jcersj2.20100

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DOI： 10.2109/jcersj2.20141

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DOI： 10.1016/j.matchemphys.2020.122988

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.materresbull.2019.110762

Language：English   Publishing type：Research paper (scientific journal)  

© 2020 American Chemical Society. Four types of bismuth oxides, Na3Bi3O8, NaBiO3, α-Bi2O3, and ϵ-Bi2O3, were obtained by hydrothermal reactions using NaBiO3·nH2O in NaOH solution. The crystal structure of a new phase (Na3 Bi3+)Bi25+O8 ((Na0.75Bi0.25)2BiO4) was determined by using single crystal X-ray diffraction data, and this compound was found to show a Na2MnCl4-related structure with a monoclinic system (space group, Pm) with the following lattice parameters: a = 5.990 (2) Å, b = 3.335 (2) Å, c = 10.108 (2) Å, and β = 91.08 (3)°. The final R-factors R1 and wR2 were 0.041 and 0.090 (all data), respectively. The new phase was composed of mixed valence states of Bi (Bi3+ and Bi5+, with a mean Bi valence of 4.30) with five distinct Bi sites, where two Bi5+ (Bi1 and Bi2) fully occupied the distorted octahedral sites and three Bi3+ (Bi3, Bi4, and Bi5) were statistically distributed at the split sites with Na+ (Na3, Na4, and Na5). The Na6 site is fully occupied. The distorted Bi5+O6 octahedra formed one-dimensional chains via edge-sharing along the b-axis, with the chains held by Bi3+/Na+ split sites. The structural feature except for the split distribution of Bi3+/Na+ was classified as a Na2MnCl4-type structure. DFT calculations based on a model discounting the split distribution of Bi3+/Na+ indicated that Bi 6s and O 2p orbitals form sp hybridization at the conduction band. This new mixed valence bismuth oxide exhibited photocatalytic activity for phenol degradation under visible light irradiation. In addition to Na3Bi3O8, the hydrothermal reaction using NaBiO3·nH2O in NaOH solution yielded micrometer-sized single crystals of an ilmenite-type NaBiO3 and two polymorphs of bismuth oxides with monoclinic (α-Bi2O3) and orthorhombic (ϵ-Bi2O3) structures, depending on the reaction temperature and NaOH concentration.

DOI： 10.1021/acs.inorgchem.0c00213

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PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Taylor&Francis  

DOI： 10.1080/21870764.2020.1712799

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAE International  

DOI： 10.4271/05-13-01-0003

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ceramic Society of Japan  

DOI： 10.2109/jcersj2.19139

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2109/jcersj2.19093

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DOI： 10.1016/j.apsusc.2019.143872

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DOI： 10.1016/j.matlet.2019.126688

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DOI： 10.2109/jcersj2.19080

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DOI： 10.1021/acs.inorgchem.9b01768

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/21870764.2019.1649041

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DOI： 10.1016/j.materresbull.2019.02.023

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI  

DOI： 10.3390/molecules24050976

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acs.inorgchem.6b01853

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2109/jcersj2.18052

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acs.inorgchem.8b01003

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2109/jcersj2.18065

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DOI： 10.2109/jcersj2.18064

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DOI： 10.5182/jaie.29.48

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DOI： 10.5182/jaie.29.131

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DOI： 10.1021/acs.inorgchem.8b00799

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DOI： 10.1080/21870764.2018.1504708

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI  

Cr-based layered double hydroxides (LDHs) containing Ni, Zn, or Cu as the divalent cation were prepared with a divalent-totrivalent cation molar ratio of 3. Then, LDH hybrids intercalated with polyanions ([PMo12O40](3-1) (PMoO) or [H2W12O42] 10 1 (HWO)) were prepared by ion exchange and hydrothermal processes. The shift of the diffraction line indicating interlayer space in the X-ray diffraction patterns confirmed the intercalation in the LDH. The fraction of PMoO and HWO anions incorporated was 30-70 or 60-90% of ion exchange capacity, respectively, by charge compensation for Cr3+. In the conversion of styrene by epoxidation and oxidation, the hybrid of the LDH composed of Zn and Cr with PMoO showed the maximum catalytic activity, with 70% conversion. For the LDH composed of Ni and Cr, hybridization with a polyanion enhanced the catalytic behavior by a synergistic effect resulting from the basicity of the LDH phase. (C) 2017 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.17060

Web of Science

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI  

Mesoporous silica-phosphate hybrids were successfully prepared by three processes: hybridization post synthesis by H3PO4, hybridizations during synthesis by Na2HPO4 and by PO(OC2H5). X-ray diffraction patterns confirm that the hexagonal pore structure was maintained after the hybridization process. The maximum phosphate amount was 2.9 mol% in the sample prepared by hybridization during synthesis from Na2SiO3 and PO(OC2H5)(3). The specific surface area showed a large value of approximately 1000 m(2)/g despite the hybridization. The Si-O-P bonds were confirmed by nuclear magnetic resonance and X-ray photoelectron spectroscopy. The maximum adsorption amount of rare earth metal cations into the hybrid was approximately 70% of the initial concentration (50 mg/L) for each rare earth metal cation in coexistence with 13 rare earth metal cations. (C) 2017 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.17066

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI  

Pyrochlore-type (K0.73H0.27)NbO3 center dot 1.72H(2)O and (K0.56H0.44) TaO3 center dot 1.14H(2)O were synthesized by a hydrothermal reaction. The K+ ions in these compounds were reacted with Ag+ ions in excess molten AgNO3 at 300 degrees C. This reaction produced fluorite-type Ag0.41Nb0.59O1.68 and pyrochlore-type Ag(0.93)TaO2.97 center dot 0.94H(2)O. Their crystal structures were refined by the Rietveld method using synchrotron X-ray powder diffraction data. Only the pyrochlore-type Ag(0.93)TaO2.97 center dot 0.94H(2)O exhibited photocatalytic activity toward phenol degradation under UV light irradiation. (C) 2017 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.17063

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

The pentavalent bismuthate BaBi2O6 was prepared by a low-temperature hydrothermal reaction using NaBiO3.nH(2)O and Ba(OH)(2).8H(2)O as starting materials. The X-ray powder diffraction pattern was indexed with a hexagonal cell (space group: P-31m), the same as a PbSb2O6-type crystal. The crystal structure of this compound was refined using synchrotron X-ray powder diffraction data. The cell parameters were found to be a=5.57534(6) and c=5.7381(1) angstrom and the final reliability (R) factors obtained by Rietveld analysis were R-wp=5.15% and R-p=3.62%. This compound exhibited profound photocatalytic activity for phenol decomposition under visible light irradiation.

DOI： 10.1002/slct.201700973

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

Rutile-type solid solutions
Ni1−xCoxTi(Nb1−yTay)2O8 (0 ≤ x ≤ 1, 0 ≤ y ≤ 1) were prepared by high temperature solid state reaction. The solid solutions of noibates (y = 0) had a rutile-type structure and those of tantalates (y = 1.0) had a trirutile-type one. The trirutile-type structure appeared in the composition of y ≥ 0.4. The crystal structures of these solid solutions for niobates and tantalates were refined by using synchrotron X-ray powder diffraction data and the R-factors were Rwp = 1.76–1.92% and Rp = 1.13–1.19% for niobates and Rwp = 10.3–12.2% and Rp = 6.78–9.14% for tantalates. Their lattice parameters for noibates ranges from a = 4.69413(2) to 4.70411(2) Å and c = 3.02187(1) to 3.03242(1) Å and those for tantalates ranges from a = 4.6946(2) to 4.7065(2) Å and c = 9.0829(3) to 9.1164(4) Å. The optical band gap for these solid solutions ranged from 1.63 to 2.50 eV and only NiTiTa2O8 exhibited photocatalytic activity for phenol decomposition under UV light irradiation. The dielectric constants for four end members, NiTiNb2O8, CoTiNb2O8, NiTiTa2O8 and CoTiTa2O8 were 25–75 in the temperature range from room temperature to 300 °C.

DOI： 10.1016/j.jascer.2017.05.005

Scopus

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acs.inorgchem.6b01853

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

A new lithium copper bismuth oxide, LiCuBiO4 was prepared by hydrothermal reaction using NaBiO3.1.4H(2)O. The crystal structural model of this compound was refined by using synchrotron X-ray powder diffraction data. This bismuthate has the LiCuSbO4 related structure with the orthorhombic cell (Space group: Pnma) of a=10.9096(9), b=5.8113(5) and c=5.0073(4) angstrom, and the final R-factors were R-factors were R-wp=4.84 and R-p=3.58%. This compound is the first example of a lithium copper bismuthate containing Bi5+ An antiferromagnetic ordering of Cu2+ moment was observed at 6 K.

DOI： 10.1016/j.jssc.2016.10.003

Web of Science

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Adsorption competencies of rare earth metal cations in gamma-zirconium phosphate were examined by ICP, synchrotron X-ray diffraction (SXRD), and ab initio simulation: The adsorption amounts are around 0.06-0.10 per zirconium phosphate. From the SXRD patterns of the adsorbed samples, the basal spacing estimated by c sin beta increased linearly with an increasing ionic radius of rare earth metal cation, though a and b lattice constants show no change. These SXRD patterns Can be classified into four groups that have different super lattices. The four superlattices have multiplicities of x131, x241, and x221 for the xabe axis, and the location of the rare earth metal cation in the original unit cell changes depending on the superlattice cell. In the x131 superlattice, Yb and Et occupied the site near the zirconium phosphate layer, though La and Ce in the x221 superlattice remained in the center position between the phosphate sheet. For the ab initio simulation of gamma-ZrP with the typical rare earth metal cations (Tb, Eu, Dy, and La), the results of simulation show a similar tendency of the position estimated by SXRD refinements.

DOI： 10.1021/acs.langmuir.6b02747

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A new high-pressure polymorph of NaBiO3 (hereafter beta-NaBiO3) was synthesized under the conditions of 6 GPa and 600 degrees C. The powder X-ray diffraction pattern of this new phase was indexed with a hexagonal cell of a = 9.968(1) angstrom and c = 3.2933(4) angstrom. Crystal structure refinement using synchrotron powder X-ray diffraction data led to R-WP = 8.53% and R-P = 5.55%, and the crystal structure was closely related with that of Ba2SrY6O12. No photocatalytic activity for phenol decomposition was observed under visible-light irradiation in spite of a good performance for its mother compound, NaBiO3. The optical band-gap energy of beta-NaBiO3 was narrower than that of NaBiO3, which was confirmed with density of states curves simulated by first-principles density functional theory calculation.

DOI： 10.1021/acs.inorgchem.6b00947

Web of Science

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Topotactic transformation of film-shaped samples comprising a layered double hydroxide (LDH) to a metal oxide phase was performed by a hydrothermal or heat treatment The degree of transformation was examined by X-ray photoelectron spectroscopy (XPS) and synchrotron X-ray diffraction (SXRD). The LDH film prepared as a raw material by a reflux process with urea was composed of plate-shaped particles that were partially perpendicular to the substrate. For the transformation, the LDH powder and film were treated hydrothermally at 90, 120, and 200 degrees C in a LiOH aqueous solution or heated to 400, 600, and 800 degrees C with a LiOH center dot H2O contact. The film shape and morphology of the LDH particles were retained after the hydrothermal treatment at 120 degrees C. XPS and SXRD confirmed that two types of LDH with different compositions, Ni:Co = 62:38 and 90:10, were formed in the as-prepared LDH. In the case of the sample treated hydrothermally, metal hydroxide with no intercalated anion within the interlayer space was observed and the metal oxyhydroxide formed with a ratio of approximately 15%. For the heated samples, the transformation to LiNi1-xCoxO2-related materials was carried out by heating to 600 or 800 degrees C. 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.clay.2016.02.018

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Double-perovskite Bi oxides are a new series of superconducting materials, and their crystal structure and superconducting properties are under investigation. In this paper, we describe the synthesis and characterization of a new double-perovskite material that has an increased superconductive transition temperature of 31.5 K. The structure of the material was examined using powder neutron diffraction (ND), synchrotron X-ray diffraction (SXRD), and transmission electron microscopy (TEM). Rietveld refinement of the sample based on ND and SXRD data confirmed an A-site-ordered (K-1.00)(Ba-1.00)(3)(Bi0.89Na0.11)(4)O-12 double-perovskite-type structure with the space group Im (3) over barm (No. 229). This structural analysis revealed the incorporation of Na with Bi in the structure and a bent bond between (Na, Bi)-O-(Na, Bi). TEM analyses also confirmed a cubic double-perovskite structure. This hydrothermally synthesized compound exhibited a large shielding volume fraction, exceeding 100%, with onset of superconductivity at similar to 31.5 K. Its electrical resistivity dropped near onset at similar to 28 K, and zero resistivity was confirmed below 13 K. The calculated band structure revealed that the metallicity of the compound and the flatness of the conduction bands near the Fermi level (E-F) are important for the appearance of superconductivity.

DOI： 10.1021/acs.chemmater.5b02386

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The relationship between the structure and superconductivity of Bi4O4S3 powders synthesized by heating under ambient and high pressures was investigated using synchrotron X-ray diffraction, Raman spectroscopy, and transmission electron microscopy (TEM) observation. The Bi4O4S3 powders synthesized under ambient pressure exhibited a strong superconductivity (diamagnetic) signal and zero resistivity below similar to 4.5 K, while the Bi4O4S3 powder synthesized by the high-pressure method exhibited a low-intensity signal down to 2 K. Further annealing of the latter Bi4O4S3 powder under ambient pressure led to the development of a strong signal and zero resistivity. The crystal structures of all Bi4O4S3 phases consisted of Bi4O4Bi2S4 blocks including a Bi-S layer and anion(s) sandwiched between Bi4O4Bi2S4 blocks, but minor structural differences were detected. A comparison of the structures of the superconductive and nonsuperconductive Bi4O4S3 samples suggested that the superconductive Bi4O4S3 phases had slightly smaller lattice parameters. The average structures of the superconductive Bi4O4S3 phases were characterized by a slightly shorter and less bent BiS plane. Raman spectroscopy detected vibration of the S-O bonds, which can be attributed to sandwiched anion(s) such as SO42-. TEM observation showed stacking faults in the superconductive Bi4O4S3 phases, which indicated local fluctuation of the average structures. The observed superconductivity of Bi4O4S3 was discussed based on impurity phases, enhanced hybridization of the px and py orbitals of the Bi-S plane within Bi4O4Bi2S4 blocks, local fluctuation of the average structures, compositional deviation related to suspicious anion(s) sandwiched between Bi4O4Bi2S4 blocks, and the possibility of suppression of the charge-density-wave state by enriched carrier concentrations.

DOI： 10.1021/acs.inorgchem.5b01919

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Crystallographic and electronic structures of Nb-, Mo-, Ta-, and W-based layered oxides, oxynitrides, and nitrides were analyzed to elucidate the structural relationship between layered oxides and nitrides consisting of octahedral and trigonal-prismatic layers. The electron density, as derived by synchrotron X-ray analysis of LiNbO2 and Ta5-x(O,N)(6), showed orbital overlaps between Nb-Nb and Ta-Ta metals in the trigonal layers. Computational calculations based on DFT exhibited that these overlaps stabilized these structures by lowering the hybridization states composed of the d(xy), d(x2-y2), and d(z2) orbitals below the Fermi level. Crystal structures and formation energies suggest that tuning the Fermi level through the substitutions and vacancies of the cation/anion sites determines the structural preferences of the coordination. The properties and syntheses of these compounds are briefly described. This study enhances the understanding of layered oxides, oxynitrides, and nitrides to further the development of new synthetic approaches, compounds, and applications. (C) 2015 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jssc.2015.06.028

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Alkaline earth metal doped tin oxide (SnO2) hollow nanospheres with a diameter of 50 nm have been synthesized successfully via a facial solvothermal route in a very simple system composed of only ethanol, acetic acid, SnCl4 center dot 5H(2)O and A(NO3)(2)center dot xH(2)O (A = Mg, Ca, Sr, Ba). The synthesized undoped SnO2 and A-doped SnO2 hollow nanospheres were characterized by the oxygen storage capacity (OSC), X-ray diffraction, transmission electron microscopy and the Brunauer-Emmet-Teller (BET) technique. The OSC values of all samples were measured using thermogravimetric-differential thermal analysis. The incorporation of alkaline earth metal ion into tin oxide greatly enhanced the thermal stability and OSC. Especially, Ba-doped SnO2 hollow nanospheres calcined at 1000 degrees C for 20 h with a BET surface area of 61 m(2) g(-1) exhibited the considerably high OSC of 457 mu mol-O g(-1) and good thermal stability. Alkaline earth metal doped tin oxide has the potential to be a novel oxygen storage material. (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.materresbull.2014.11.018

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

Two new cadmium bismuthates, CdBi2O6 and Cd0.37Bi0.63O1.79, were prepared by hydrothermal reaction using NaBiO3·nH2O as one of the starting compounds. The crystal structures of these compounds were refined by using synchrotron X-ray powder diffraction data. The former bismuthate has a MnSb2O6-type structure with a hexagonal cell (space group: P321)
the cell parameters were a=9.3641(7) and c=4.9523(3)Å, and the final R-factors were Rwp=4.59% and Rp=3.04%. The latter bismuthate has a fluorite-type structure with a cubic cell (space group: Fm3-m) of a=5.4110(4)Å, and the final R-factors were Rwp=4.79% and Rp=3.57%. These new bismuthates exhibit no photocatalytic activity under visible light.

DOI： 10.1016/j.jascer.2015.04.003

Scopus

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI  

Ag-intercalated and Bi-intercalated layered perovskite were fabricated by ion-exchanged process. The XRD and XPS confirm the phase transformation of the Ag-ion exchanged layered perovskite from Dion-Jacobson to Ruddlesden-Popper phase by heating at higher than 200 degrees C. In the case of Bi ion-exchange perovskite, the product remained Dion-Jacobson phase during the heat treatment. For the Ag-intercalated sample, Ruddlesden-Popper type photocatalyst by heating at 500 degrees C can degrade 20 ppm phenol solution to 6ppm in 3 h under Xe light, which has superior photocatalytic activity to Dion-Jacobson phase Ag0.67H0.33LaNb2O7. For the Bi-intercalated sample, Dion-Jacobson type photocatalyst can degrade phenol from 20 to 12 ppm in 3 h. From first principle DFT simulation, high photocatalytic activity may be due to the new Ag 4d, O 2p and Nb 4d hybridized band at the highest of the valence band for Ag-included, and to the new Bi 6p band at the lowest of the conduction band for Bi-included samples. (C) 2015 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.123.690

Web of Science

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A novel photocatalyst consisting of an intercalated perovskite H1-2xPtxLaNb2O7 was fabricated by ion, exchange. Synchrotron X-ray diffraction and X-ray photoelectron spectroscopy results confirmed that Pt2+ exists within the interlayer space of the layered perovskite: H1-2xPtxLaNb2O7 composed of layered niobate perovskite. and intercalated Pt2+ completely degraded a 20 ppm phenol solution in 3 h under irradiation by Xe light, which exhibits photocatalytic activity superior to those of RbLaNb2O7, Pt-deposited RbLaNb2O7, and HLaNb2O7. From first-principles density functional theory simulation, high photocatalytic activity Of H1-2xPtxLaNb2O7 is attributed to the emergence of a new O 2p-Pt 5d hybridized band on top of the valence band.

DOI： 10.1021/acs.langmuir.5b01958

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jallcom.2014.12.274

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PHYSICAL SOC JAPAN  

We have studied the structural, magnetic, and dielectric properties of the dimer-Mott insulator beta'-(BEDT-TTF)(2)(ICl2)(1-x)(AuCl2)(x). The AuCl2 substitution for ICl2 decreases the lattice length in the interlayer direction, leading to uniaxial chemical pressure with a negligible effect on the intralayer donor stacking. The variation of the Neel temperature as a function of x is explained on the basis of chemical pressure accompanied by anion disorder, while the dielectric response does not indicate the effect of chemical pressure. This suggests that the charge degrees of freedom are attributed to the intralayer origin such as the charge fluctuation of donor molecules induced by an electric field.

DOI： 10.7566/JPSJ.84.033709

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Single crystals of Cu(In,Ga)S-2 were successfully grown using CsCl flux in vacuum The grown single crystals were typically 3-4 mm with unshaped form. The Cu(In,Ga)S-2 single crystals with various Ga concentration were obtained by control of the Ga concentration in the starting materials. The optical band-gaps of obtained single crystals were estimated from the reflectance spectrum The optical band-gap changed between 142 and 240 eV at room temperature with dependence on the Ga concentration. (C) 2014 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jcrysgro.2014.11.018

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The crystal structures of Ce(O,F)BiS2 synthesized from starting materials with five different F contents were determined by single-crystal X-ray analysis. An increase in F content in the starting materials slightly increased F incorporation in the grown single crystals. The grown crystals with various F contents showed similar layered structures, but minor structural changes were observed with different conductive and magnetic properties. Crystals grown from higher F content were found to have a nearly flat Bi-S plane and elongated Ce-(O,F) bond, and showed superconductive transition below similar to 3 K and spontaneous magnetization below similar to 7 K. The calculated density of states based on this structural analysis predicted that hybridized Bi 6p-S 3p orbitals intersect the Fermi level and that Ce states are located near the Fermi level. The effect of structural change on superconductivity and long-range magnetic ordering has been discussed.

DOI： 10.1021/cg5005165

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jascer.2014.08.007

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jascer.2014.08.007

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

A layered perovskite was fluorinated by polytetrafluoroethylene (PTFE) and then exfoliated to prepare a solution of fluorinated-perovskite nanosheets. Dion-Jacobson-type layered perovskites, RbLaNb2O7 and KCa2Nb3O10, were prepared in solid-state reactions at 950 and 1100 degrees C, respectively. The perovskites were fluorinated using PTFE at 400 degrees C, upon which their color changed from white to gray or black and their electrical conductivity increased to the order of 10(-4)-10(-5) S/m. The tetrabutyl ammonium cations(TBA(+)) in each fluorinated layered perovskite were first intercalated by tetrabutylammonium hydroxide(TBAOH) in H2O and then exfoliated in an acetonitrile solution for electrodeposition. Aniline was added to the solution as a monomer and electrodeposition was carried out in the acetonitrile solution for formation of a hybrid film. X-ray diffraction patterns confirmed that the polyaniline molecules could be intercalated within the interlayer space. Despite the fluorination, the volumetric filling fractions of polyaniline in the interlayer space were around 0.4 and 0.2 for the respective samples from RbLaNb2O7 and KCa2Nb3O10. The electrochemical specific capacitances of the deposited hybrid films increased steeply from below 50 F/g to above 230-250 F/g owing to the fluorination. (C) 2014 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.colsurfa.2014.07.001

Web of Science

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

Co-Al and Ni-Al layered double hydroxides (LDHs) intercalated with three types of anionic molecules, dodecylsulfate (C12H25SO4-, DS), di-2-ethylsulfosuccinate ([COOC2H3EtBu]2C2H3SO3-, D2ES), and polytungstate (H2W12O4210-, HWO) were prepared by means of ion-exchange and co-precipitation processes. With the use of DS and D2ES as intercalation agents, high crystallinity was maintained after intercalation into the LDHs. In the case of HWO, the intercalated LDHs could be obtained by ion-exchange as well as co-precipitation with a decline in the crystallinity
however, unreacted LDH was detected in the ion-exchange samples, and some unwanted phases such as hydroxide and pyrochlore were generated by the co-precipitation process. The maximum specific surface area and pore volume of the Ni-Al sample with intercalated HWO, prepared by the ion-exchange process were 74m2/g and 0.174mL/g, respectively. The occupancies of DS, D2ES, and HWO within the interlayer space were approximately 0.3-0.4, 0.5-0.6, and 0.1-0.2, respectively, in the Co-Al and Ni-Al LDHs. Analysis of the catalytic activity demonstrated that the DS-intercalated Ni-Al LDH sample exhibited relatively good catalytic activity for conversion of cyclohexanol to cyclohexanone. © 2014 The Ceramic Society of Japan and the Korean Ceramic Society.

DOI： 10.1016/j.jascer.2014.06.002

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2109/jcersj2.122.307

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jascer.2014.02.002

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/anie.201400607

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jssc.2014.01.035

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2109/jcersj2.122.307

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

The crystal structures of FexWN2 (x similar to 0.74, 0.90) and their magnetic properties were investigated. The structural studies reveal the formation of ion defects with different concentrations in the two-dimensional iron triangular lattice by analyzing the synchrotron radiation X-ray diffraction data. The magnetic measurements demonstrate that the Fe0.74WN2 phase shows ferromagnetism at 300 K, while the less defective Fe0.90WN2 phase exhibits no ferromagnetism. A decrease of temperature to 5 K significantly suppresses the room-temperature ferromagnetism of the Fe0.74WN2 phase. We attribute the emergence of ferromagnetism in FexWN2 to the increases of defect concentration and thermal displacement in the iron triangular lattice. (C) 2014 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jallcom.2014.01.030

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Nickel hydroxide (beta-Ni(OH)(2)) nanosheets with a diameter of 400 nm and a thickness of 20 nm were successfully synthesized by a template and surfactant-free solvothermal route in a very simple system composed of LiOH center dot H2O and Ni-naphthenate. Furthermore, porous nickel oxide (NiO) nanosheets were obtained by thermal decomposition of beta-Ni(OH)(2) nanosheets in air at 350-550 degrees C for 2 h. HRTEM and SAED results revealed that the microporous NiO nanosheets obtained at 350 degrees C were single-crystalline, and nitrogen adsorption-desorption measurements of the BET surface area and pore size of porous NiO nanosheets were 156 m(2) g(-1) and 1.7 nm, respectively. Moreover, mesoporous NiO nanosheets and macroporous NiO nanosheets could be selectively obtained by controlling thermal decomposition temperature. The formation mechanism of porous NiO nanosheets was discussed. The magnetic property and photocatalytic activity of the porous NiO nanosheets were also investigated. The porous NiO nanosheets showed enhanced photocatalytic activity for NO destruction. (C) 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.apcatb.2013.10.007

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2109/jcersj2.122.86

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

F-substituted ROBiS2 (R=La, Ce, Nd) superconducting single crystals with different F concentrations were grown successfully using a CsCl/KCl flux. All crystals produced had a plate-like shape, with a well-developed ab-plane 1-2 mm in size. Electron probe microanalysis did not detect any Cs, K, or Cl flux components in the crystals. As-grown single crystals of F-substituted LaOBiS2 and CeOBiS2 exhibited superconductivity at about 3 K, whereas F-substituted NdOBiS2 was superconductive at approximately 5 K. The superconducting anisotropy of single crystal F-substituted LaOBiS2 and NdOBiS2 was estimated to be 30-45 according to the effective mass model, whereas the anisotropy for F-substituted CeOBiS2 single crystals was 13-21. The F-substituted CeOBiS2 single crystals exhibited a magnetic order around 7 K that apparently coexisted with superconductivity below approximately 3 K. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.ssc.2013.10.019

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

F-substituted NdOBiS2superconducting single crystals were grown using CsCl/KCl.ux. This is the.rst example of the single-crystal growth of a BiS2-based superconductor. The obtained single crystals had a plate-like shape with a size of 1-2mm and a well-developed ab-plane. The crystal structure of the grown crystals was determined by singlecrystal X-ray di.raction analysis to be the tetragonal space group P4=nmm (29) with a = 3:996(3) and c = 13:464(6)Å. The chemical formula of the grown crystals was approximately Nd0.98±0.06O 0.7±0.1F0.3±0.1Bi 0.98±0.04S2, and Cs, K, and Cl were not detected in the grown crystals by electron probe microanalysis. The grown crystals had a critical temperature of approximately 5K. The superconducting anisotropy of the single crystals was estimated to be about 30 from the e.ective mass model and the upper critical.eld. © 2013 The Physical Society of Japan.

DOI： 10.7566/JPSJ.82.113701

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/ic401951u

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Layered double hydroxides (LDH) containing Co or Ni as the divalent cation and Al or Fe as the trivalent cation were prepared by hydrothermal treatment. The LDH phase containing Al can be prepared at a pH of ca. 7, whereas the LDH phase containing Fe can be prepared at pH 10. The chemical composition of the LDH was estimated by the calculation of the weighted mean electronegativity of the cations present in the aqueous metal solution. The decarbonated LDHs are intercalated by sodium dodecyl sulfate and can be exfoliated in 1-butanol solution by ultrasonication. The resulting LDH aggregates with a card-house structure that can then be deposited from these exfoliated colloidal solutions by sodium carbonate. For Ni/Al and Ni/Fe LDHs, in particular, the specific surface area and pore volume drastically increased owing to the card-house texture formed by exfoliation and redeposition. © 2012 Springer Science+Business Media New York.

DOI： 10.1007/s10934-012-9652-4

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Carbon, nitrogen, and oxygen are essential components in solid-state materials. However, understanding their preference on the bonding to metals has not been straightforward. Here, niobium carbide, nitride, and oxide with simple rock-salt-based structures were analyzed by first-principles calculations and synchrotron X-ray diffraction. We found that an increase in the atomic number from carbon to oxygen formed fewer and shorter bonds to metals with better hybridization of atomic orbitals. This can provide a simple guiding principle for understanding the bonding and designing carbides, nitrides, oxides, and mixed-anion compounds. © 2013 American Chemical Society.

DOI： 10.1021/ic400830b

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ceramic Society of Japan  

Three solid solutions [(1-x)LNN-xBaTiO3 (BT), xBaZrO3 (BZ) and xK0.5Ba0.5Ti0.5Nb0.5O 3(KBTN)] based on (Li0.12Na0.88)NbO 3(LNN) with the rhombohedral symmetry were prepared by conventional solid state reaction and their dielectric property was investigated. In the LNN-BT system in x ≤ 0.6 a secondary phase was observed as well as the perovskite-type phase and the psudo-cubic and tetragonal single phases were observed in 0.7 ≤ x ≤ 0.94 and 0.95≤ x ̄ 1.0, respectively. In LNN-BZ and LNN-KBTN systems single phases of the compounds with the rhombohedral symmetry were formed in x ≤ 0.05. The length of the a-axis increased with content of BZ or KBTN and that of the c-axis was almost unchanged except x = 0.1 for LNN-BZ. The secondary phase with the tetragonal tungsten bronze-type (TTB) structure was observed in wide composition range of these solid solutions, and LixBa2NaNb5-xMxO15(M: Ti, Zr) with the TTB-type structure was prepared and their crystal structure and dielectric property were investigated. ©2013 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.121.544

Scopus

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Calcium sulfite waste was successfully transformed to hydroxyapatite (HAp) by oxidation using H2O2, followed by reaction with (NH4)2HPO4 under an NH4OH atmosphere. A single phase hydroxyapatite was obtained by stirring at 60, 80, or 100°C rather than by hydrothermal treatment at 150°C. Such formation implied that the homogeneity of the solution was very important. The primary HAp particles obtained had columnar shape, which formed spongy secondary particles with a diameter of around 1μm. Such porous particles resulted from the dissolution rate of calcium sulfite. The HAp obtained had a relatively Ca-rich composition of around Ca/P=1.71, and the specific surface area was around 69m2/g. In adsorption tests for Cs+ and Cd2+ cations in artificial seawater, the prepared HAp, like the general HAp powder, could remove Cd2+ cations from the seawater. © 2012 Elsevier B.V.

DOI： 10.1016/j.powtec.2012.12.022

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Materials Research Society of Japan  

Fine particles of BiFeO₃ were prepared from bismuth nitrate and iron nitrate in KOH solution by hydrothermal reaction. A single phase of BiFeO₃ was prepared under hydrothermal condition of K/Bi ≥ 120 and above 180 °C. The TG curves of single phase of BiFeO₃ indicated that the products included a small amount of OH group or water in spite of no detection of potassium atom by EDX. The particle size of BiFeO₃ was ～ 10 μm and 10 ～ 20 μm for the products at 180 and 220 °C, respectively. The particle prepared at 220 °C was formed by aggregation of ～ 10 nm size particles with a cubic shape. From the pH dependence of ζ-potential the isoelectric point was about three.

DOI： 10.14723/tmrsj.38.53

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

The effect of dispersion of sepiolite in a sepiolite-NBR composite on the tensile strength of the composite was examined. Fibrous sepiolite was ultrasonically treated in distilled water with various types of dispersant. The ultrasonicated sepiolite was mixed with NBR latex to form a sepiolite-NBR complex. The tensile strength of the complex was examined to evaluate the degree of dispersion of sepiolite. The tensile strength results for the composites confirmed that a lower ultrasonication frequency produced a high strength in the composite. The tensile strength actually increased from 3 to 8 MPa as a result of ultrasonication at 28 kHz. To improve and stabilize the dispersion state, five kinds of dispersant were used. The addition of two dispersants in particular, ammonium polycarboxylate and amino alcohol polyphosphate, resulted in an increase of the strength from 8 to 15-16 MPa. When the composites were heated at 450 degrees C, the strengths of the composites produced with and without the dispersant were approximately 1.4-1.7 and 0.85 MPa, respectively. Thus, the dispersant still affected the strength of the heated samples. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.compositesb.2012.05.034

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

A new layered niobate, Mg 0.5NbO 2, was synthesized from LiNbO 2 through a cation-exchange reaction with Mg 2 at 450-550 °C. This is the first example of a topotactic reaction with an aliovalent cation between trigonal [NbO 2] - layers. It is proposed to be isostructural with LiNbO 2 (space group
P6 3/mmc) with lattice parameters of a=2.9052(6) Å, c=10.625(15) Å. The lattice parameters and formation energy of Mg 0.5NbO 2 crystallized in LiNbO 2 form and other layered CaNb 2O 4 one were calculated by density functional theory. © 2012 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jssc.2012.08.027

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI  

Alkaline earth metal titanates ATiO(3) (A: Mg, Ca, Sr, Ba) were prepared from two types of layered potassium titanates [K2Ti2O5 and K0.6Ti1.85O4 (hereafter, Lss)] by using alkaline earth metal molten salts [ACl(2) + A(NO3)(2) (1:1)]. For A = Ca a single phase of perovskite-type compound was prepared at 600 degrees C by using both starting compounds and the reaction temperature was lower than in 400 degrees C that of the solid state reaction with TiO2 (anatase) and CaCO3. A single phase of perovskite-type SrTiO3 was obtained at 600 and 700 degrees C for K2Ti2O5 and Lss, respectively and these temperatures were much lower than that (1200 degrees C) of the solid state reaction with TiO2 (anatase) and SrCO3. In the case of perovskite-type BaTiO3 a single phase of perovskite-type compound was prepared at 700 degrees C by using both starting compounds and also this temperature was much lower than that (above 1300 degrees C) of the solid state reaction with TiO2 (anatase) and BaCO3. Although neither K2Ti2O5 nor Lss could produce a single phase of ilmenite-type MgTiO3, it was prepared by the solid state reaction with TiO2 (anatase) and magnesium basic carbonate at 900 degrees C. A single phase of ilmenite-type CdTiO3 was prepared from K2Ti2O5 by using cadmium molten salts [CdCl2 + Cd(NO3)(2) (1:1)] at 500 degrees C. By taking account of the fact that ilmenite-type CdTiO3 transforms to perovskite-type structure, this preparative method using layered potassium titanates with molten salts preferred to crystallize perovskite-type titanates at lower temperature rather than ilmenite-type ones. (C)2013 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.121.74

Web of Science

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI  

One of the calcium aluminate, 12CaO center dot 7Al(2)O(3), was synthesized from calcium sulfite hemihydrate waste which was produced as a by-product of calcium polysulfide. The calcium sulfite waste was at first pre-treated by sodium salts, Na2CO3 and Na2C2O4. Then, the waste was converted to the CaCO3 and CaC2O4, respectively. From these pre-treated sample, 12CaO center dot 7Al(2)O(3) phase was formed at 850 degrees C for the converted CaCO3 from Na2CO3 and at 650 degrees C for the converted CaC2O4 from Na2C2O4. These crystallization temperatures are much lower than from reagent CaCO3 and CaC2O4 at 1250 and 850 degrees C, respectively. The reason of such reduction of crystallized temperature may result from impurity Fe2O3 including in the by-product. Actually, addition of Fe2O3 into the reagent CaCO3 posed decrease of crystallization temperature of 12CaO center dot 7Al(2)O(3) from 1250 to 1050 degrees C. (C)2013 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.121.31

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Nitridation of oxides above 500 degrees C is a conventional route for the synthesis of various oxynitrides and nitrides. However, this technique has the disadvantages of requiring a high temperature to break the strong metal and oxygen bonds and of low utilization efficiency of nitrogen sources such as toxic ammonia. Here, we show a simple low-temperature synthesis of InN nanocrystals via the nitridation of LiInO2 by NaNH2 flux at 240 degrees C in a Teflon-lined autoclave. The NaNH2 flux converted irregular-shaped LiInO2 powder to 50-300 nm InN nanocrystals with well-developed facets. The product crystallized in the hexagonal wurtzite structure with lattice parameters of a = 3.545 angstrom and c = 5.717 angstrom. Lithium in the starting oxide was found to be essential for this low-temperature nitridation.

DOI： 10.1021/cg3007266

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

The stability of Chinese sepiolite with respect to acid, base, and heat treatments was examined based on changes that occur in its crystal structure, its morphology, its surface area, and the ions that leach into solution. Treatment in HCl for 3 h caused predominantly Mg2+ to leach and increased the surface area of the sepiolite. Increased temperature accelerated the leaching, resulting in the disappearance of the sepiolite phase above 100 degrees C. Treatment in NaOH caused Si4+ to be leached and this was accompanied by a minor change in the crystal structure of the sepiolite. Thermal treatment in air caused the manifestation of several types of dehydration behavior and the sepiolite was decomposed completely at above similar to 800 degrees C. Composite sheets of sepiolite and nitrile butadiene rubber were made from sepiolite after it had undergone various treatments. The tensile stress of each composite was measured and this is discussed with respect to its degradation features. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

DOI： 10.1016/j.ceramint.2012.02.050

Web of Science

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Porous materials were prepared from colored waste glass by hydrothermal treatment with Na2CO3 aqueous solution. The resultant specific surface area was approximately 140 m(2)/g at maximum. Specific surface area increased at first, reached a maximum, and decreased gradually to be constant at approximately 60 m(2)/g depending on the period of hydrothermal treatment, irrespective of the concentration of Na2CO3 aqueous solution. However, the period at which the specific surface area reached maximum shortened with an increase in Na2CO3 concentration. On the other hand, the mass of the sample decreased and eventually saturated at approximately 30 mass% of the initial weight during the hydrothermal treatment. Both the dissolution of the mother glass and the formation of crystalline deposits, which were identified as calcite, zeolite-P and analcime, affected the porous structure of the treated samples. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

DOI： 10.1016/j.ceramint.2011.10.057

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Partially substituted birnessite with Fe, Co, Ni and Cu for Mn was exfoliated to form nanosheet colloid and then their electrochemical properties were examined. The partially substituted birnessite can be exfoliated by tetrabutylammonium hydroxide acetonitrile solution. The electrodeposited films was grown from the exfoliated acetonitrile solution. The electrochemical capacitance of the films once increased at low substitution ratio and decreased with increase of the ratio. Within 10 atom% of the substitution ratio, the electrochemical capacitances are larger than that of non-substituted sample. Such increase seems to be related with DOS calculated by DV-X alpha. From calculated DOS curves, the band of 3d orbital of Mn4+ tends to broaden at low substitution ratio and be restored with further increase of the substituent. The broadening results from increase of another Mn4+ circumstance, Mn4+O6 octahedron surrounded by both Mn3+ and substituent cation. (C) 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.colsurfa.2012.01.021

Web of Science

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Partially substituted proton-type birnessite were prepared by solid state reaction and their structures were refined. The formed birnessite with no substitution is identified to rhombohedral phase. In the case of substitution treatment by V and Cr for Mn, birnessite phase was not formed. On substituting Fe, hexagonal phase increased with increase of the amount of the Fe. For Co and Ni-substitution, monoclinic phase emerged at substitution ratio of around 0.37 and 0.02, respectively. For the substitution of Cu, only the monoclinic birnessite formed irrespective of the ratio. The electric conductivity of the partially substituted birnessites was examined at room temperature. The general trend is lower conductivity with increasing ratio of contained substituents. On several mol% of the substitution by Ni and Cu, the conductivity slightly increased. From DOS calculation of these compounds, the partially substitution for Mn by Fe, Co and Ni in the birnessite poses splitting of crystal field to emerge new bands at around -1 and +1 eV by Mn(IV) 3d orbital. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.materresbull.2011.07.029

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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

LiBiO(3), NaBiO(3), MgBi(2)O(6), KBiO(3), ZnBi(2)O(6), SrBi(2)O(6), AgBiO(3), BaBi(2)O(6) and PbBi(2)O(6) were synthesized by various processes such as hydrothermal treatment, heating and so on. These materials were examined for their photocatalytic activities in the decolorization of methylene blue and decomposition of phenol under visible light irradiation. For methylene blue decolorization, the presence of KBiO(3) resulted in complete decoloration within 5 min. For phenol decomposition, NaBiO(3) showed the highest activity, while LiBiO(3), SrBi(2)O(6) and BaBi(2)O(6) possessed almost comparable decomposition rates. Their decomposition rates were apparently higher than that by anatase (P25) under UV irradiation. (C) 2011 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jssc.2011.06.004

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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

A new pyrochlore-type Na0.32Bi1.68Ti2O6.46(OH)(0.44) with the cubic cell of a=10.339(5)angstrom was prepared by hydrothermal reaction using TiO2 (anatase) and Bi2O3 in NaOH solution. This compound was obtained when the molar ratio of NaOH/TiO2 was above 2 and the reaction temperature was above 240 degrees C. The TG-curve of as-prepared sample showed a mass loss of 0.8 mass% which was caused by release of OH group. This compound decomposed to a pyrochlore-type compound and a layered-type Na0.5Bi4.5Ti4O15 above 800 degrees C. The optical band gap of Na0.32Bi1.68Ti2O6.46(OH)(0.44) was estimated to be 2.5 eV. (C) 2011 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jssc.2011.04.035

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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI  

Metal-dispersed porous carbon was prepared from phenolic or furan resin mixed with Co or Ni naphthenate. The formed metal particles in these metal-dispersed porous carbons are apparently smaller than those in the metal-carbon composite prepared from metal nitrate. In the case of the metal-dispersed porous carbon prepared from phenolic resin and Co naphthenate, graphite phase was formed above 800 degrees C around Co nanoparticles. XRD patterns and TEM micrographs confirm that metal naphthenate works as a metal source from which dispersed nanosize metal particles formed. The porous carbons prepared from phenolic or furan resin with Co or Ni naphthenate have specific surface area of approx. 400 m(2)/g. For the porous carbon from phenolic resin, mesopore was formed within the sample by cracking or breaking up the large particles. These results indicate that mixing of phenol monomer and the naphthenate before polymerization results in development of mesopore. (C)2011 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.119.470

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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Single crystals of a new bismuth vanadate, Bi-3.33(VO4)(2)O-2 was prepared by hydrothermal reaction using a hydrated sodium bismuthate, NaBiO3 center dot nH(2)O as one of the starting compounds. The crystal structure was determined by using single crystal X-ray diffraction data. This compound crystallizes in the triclinic space group P (1) over bar (#2) with a = 7.114(1), b = 7.844(2), c = 9.372(2) angstrom, alpha = 106.090(7), beta = 94.468(7) and gamma = 112.506(8)degrees, Z = 2 and the final R factors are R1 = 0.052 and wR2 = 0.14 for 2085 unique reflections. The crystal structure is composed by four bismuth atoms with the coordination number of 6 or 8 and two VO4 tetrahedra, and one of four bismuth atoms is statistically distributed in the splitting sites with the distance of 0.83 angstrom. This compound exhibited photocatalytic behavior for decomposition of phenol under visible light irradiation and its activity was less than that of monoclinic BiVO4. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.materresbull.2011.02.009

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

alpha-Zirconium phosphate was chemically modified with 1,2-bis(dimethylchlorosilyl)ethane to graft organic chain, and then it was used as host material for inorganic nanosheet-polyaniline hybrid. The grafted alpha-zirconium phosphate was exfoliated in an acetonitrile solution with tetrabutylammonium salt and aniline. The electrodeposition in the presence of aniline was performed, and then it resulted in a formation of higher-order structure in which phosphate nanosheet was propped up by 1,2-bis(dimethylchlorosilyl)ethane with intrusion of polyaniline into the nanospace. The gravimetric capacitance of the alpha-zirconium phosphate without grafts and polyaniline hybrid film was around 194 F/g with the base on the amount of polyaniline mass. On the other hand, the alpha-zirconium phosphate nanosheet with grafts and polyaniline hybrid film provided larger capacitance of around 350 F/g in maximum. The nanospace formed by grafted phosphate nanosheet with 1,2-bis(dimethylchlorosily)ethane molecules gives increased amounts of polyaniline included and diffusion paths for ions.

DOI： 10.1021/la102198j

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Ternary hybrid film composed of. alpha-zirconium phosphate nanosheet, 1,2-bis(dimethylchlorosilyl)ethane and polypyrrole was prepared by anodic electrodeposition. In the hybrid film, ordered. alpha-zirconium nanosheets with grafts by silylation lay down parallel to the substrate and the polypyrrole molecules were intercalated between the nanosheets. The electrochemical measurements confirmed that the hybrid film indicated capacitive behavior and the redox activity increase by approximately 25%.

DOI： 10.3390/polym3010001

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Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Ultrafine magnetite was prepared in aqueous solution by reflux method with ethylenediamine as precipitant. On partial substitution of ethylenediamine for distilled water in the solution, the crystallite was reduced in size linearly. Ethylenediamine worked as not only a precipitant but also a inhibitor for crystal growth. Substituting ethyleneglycol for distilled water at the constant concentration of ethylenediamine, the crystallite was steeply reduced in size to around 2 nm. Specific surface area reached to around 340 m(2)/g. Such decrease of the crystallite size probably results from increase of viscosity of the solution. High viscosity of the solvent poses to decrease diffusion of iron cations to magnetite nuclei. The adsorption isotherms of O(2) and N(2) were measured at 298 K using each gas and mixed gas with ratio of 2:8. Under the existence of both the gases, the obtained magnetite adsorbed only O(2) with maximum amount of about 1.5 mass%. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.mseb.2010.01.035

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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI  

An electrodeposition was developed to prepare a hybrid film with a nano structure. An anionic nanosheet colloid solution can be prepared by the addition of quaternary ammonium with the nanosheets being electrodeposited on the anode. The redoxable electrodeposited films were grown from solutions of the manganese oxide nanosheet. On substituting from the manganese to nickel or copper with several atom % within the manganese oxide nanosheet, electric conductivity increased and the resultant electrochemical capacitance improved. Other redoxable films in which ordered phosphate nanosheets in polyaniline with monolayers were grown from solutions. These included a metal phosphate nanosheet and aniline monomer. The electrochemical capacitance of this hybrid films was approx. 180-200 F/g. Using an organo-grafted zirconium phosphate nanosheet, the graft worked as pillars to form nanovoids near to the polyaniline within the hybrid film. The resultant capacitance increased by approx. 1.8 times due to the development of an ion diffusion path. (C) 2010 The Ceramic Society of Japan All rights reserved

DOI： 10.2109/jcersj2.118.257

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Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI  

A reflux process was carried out for hybridization of aminopropyl-grafted mesoporous silica and metal cations at 110 and 140 degrees C. For the sample hybridized with Fe2+, Co2+ and Ni2+, magnetite, Co-2(OH)(3)Cl, and Ni-2(OH)(2)CO3 center dot 4H(2)O particles of approx. 5-30 nm in diameter were formed. The amount of metal compounds was approx. 9-12 mol%. These compounds formed a porous aggregate on the outer surface of the mesoporous silica particles. For the hybrid with Fe2+ and Fe3+, magnetite approx. 3 nm in diameter formed not only on the outer surface but also within the mesopores derived from the mesoporous silica. The amount of magnetite achieved approx. 30 mol%. This hybrid shows an O-2 adsorption property three times as high as the other samples. These results demonstrate that nanoscale magnetite shows significant O-2 adsorption competence at room temperature. (C) 2009 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.117.1180

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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2109/jcersj2.116.1222

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The preparation of hybrid films of metal (Ti and Sn) phosphate nanosheets and polyaniline by simultaneous electrophoretic and electrolytic deposition was performed in an acetonitrile solvent. Emeraldine polyaniline was intercalated. between the phosphate nanosheets with a monolayer arrangement. The obtained hybrid films were several tens of micrometers in thickness. The ratio of incorporated polyaniline to metal phosphate in the hybrid films reaches to around 0.45 and 0.30 at suitable concentrations of tetrabutylammonium hydroxide (TBAOH). These amounts correspond with occupancy of polyaniline in the interlayer, gallery of several tens percent. Fractions of voids in a horizontal direction were around 22 and 1% in titanium phosphate/polyaniline and-tin phosphate/polyaniline hybrid films, respectively. Thus, anodic electrodeposition makes it possible to form thick films of intercalation compounds of a-titanium and tin phosphates with polyaniline. These hybrid films were examined for redox activity. The cyclic voltammetry results of these films confirmed that the hybrid films have redox activity by polyaniline. For these voltammograms, the maximum current was observed in the tin phosphate/polyaniline hybrid deposited for 15 min. The redox activity of these hybrids possibly depends on the mesoscopic texture of the film, especially on the amount of voids in a horizontal direction.

DOI： 10.1021/la703886y

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Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Porous zirconium phosphate was prepared by silylation with organic silanes. Octylamine was intercalated into alpha-Zr(HPO4)(2)center dot H2O for expanding interlayer spacing and 1,2-bis(dimethylchlorosilyl)ethane (BMCE) was used for silylation of inorganic layers in toluene. The number of octhylamine molecules intercalated was similar to the number of phosphorus in the inorganic layers. On the other hand, that of BMCE molecule after silylating treatment was much smaller than that of phosphorus. The interlayer spacing of silylated compound was confirmed to expand via high-temperature XRD patterns and was preserved on thermal treatment up to around 500 degrees C. The maximum specific surface area of the silylated compound heated at 300 degrees C was around 70 m(2)/g, though that was smaller for silylated compounds heated at higher and lower temperature. (c) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.materresbull.2007.02.021

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DOI： 10.5182/jaie.18.604

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2109/jcersj2.115.541

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Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Porous properties of mesoporous silica silylated with various organic silanes were examined and their hydrogen adsorption properties were measured at 77 K. By silylation of the mesoporous silica, the specific surface area, pore radius and pore volume steeply decreased depending on both the size of the silane and the amount actually incorporated into the mesoporous framework. The pores reduced in size depending on the amount of modifying silane and vanished completely in the samples silylated with 3-aminopropyltrieth oxysilane and phenyltrichlorosilane. Hydrogen adsorption isotherms of the silylated samples were measured at 77 K. With the exception of the sample with phenyltrichlorosilane, hydrogen adsorption volumes were proportional to the surface area with a slope of around 1.1 molecules/2 nm. On the other hand, for the sample treated with phenyltrichlorosilane, a large hydrogen adsorption volume of around 38.1 molecules/nm(2) was obtained. On heating the silylated compounds at 500 degrees C, micropores formed and the hydrogen adsorption volume increased by 1.5 times or more due to the development of micropores. (C) 2007 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jssc.2007.01.013

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Silylation of layered zirconium hydroxy phosphate was carried out and its porous properties were examined. The novel layered hydroxy phosphate was protonated and intercalated by using octylamine to expand the interlayer space. Then, dimethyldichlorosilane, dichloromethylvinylsilane or 1,2-bisdimethylchlorosilylethane were used to silylate the interlayer space. In order to form micropores between layers, the silylated compounds were heated at the range from 100 degrees C to 1,000 degrees C to measure high-temperature XRD patterns. During heating, the interlayer spacing decreased at around 300 and 600-700 degrees C. The specific surface area reached around 180 m(2)/g as maximum area at 300 degrees C, while layered structure collapsed gradually above 400 degrees C. Micropore volume also became maximum at 300 degrees C.

DOI： 10.1007/s10853-006-1418-4

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Films of highly oriented alpha-zirconium phosphate and polyaniline- intercalated zirconium phosphate with controllable thickness in the micrometer range were grown anodically on Pt electrodes. To optimize the electrodeposition conditions, the exfoliation of alpha-zirconium phosphate by tetrabutylammonium (TBA) salts was investigated in several nonaqueous solvents. Acetonitrile was found to be the best solvent for making crack-free, oriented films because of its high vapor pressure, low viscosity, and relatively high permittivity. With TBA salts of neutral or weakly acidic anions (TBACl, TBABr, TBAI, TBA(HSO4), or TBA(H2PO4)), full exfoliation did not occur and alpha-zirconium phosphate and/or polyaniline were deposited as rough films. With basic anions (TBAF or TBAOH), dense, adherent films were obtained. X-ray diffraction patterns of the films showed that they were highly oriented along the stacking axis. The thickness could be controlled, up to about 40 Am, by limiting the time of the electrodeposition reaction. At monomer concentrations below 1.0 x 10(-2) mol/dm(3), the emeraldine form of the intercalated polymer was obtained. Electrodeposition thus provides a thick film alternative to layer-by-layer assembly for intercalation compounds of alpha-zirconium phosphate with a conducting polymer.

DOI： 10.1021/ja065677m

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A perovskite-type BaCu1/3Nb2/3O3 was prepared by high temperature reaction using BaCO3, CuO and Nb2O5. The X-ray powder diffraction pattern of this compound was indexed with the tetragonal cell with the lattice parameters of a = 4.0464(4) and c = 4.1807(4) angstrom (c/a = 1.033). This compound had the tetragonal perovskite-type structure in which the B site was occupied statistically by Nb and Cu atoms. From high temperature X-ray powder diffraction patterns this compound had a phase transition from the tetragonal to cubic symmetry in the temperature range of 500-600 degrees C. The P-E and S-E hysteresis loops occurred at room temperature and the apparent maximum in the temperature dependence of the dielectric constant was observed at 520 degrees C. The temperature dependence of the inverse of magnetic susceptibility exhibited paramagnetic behavior. (c) 2006 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jssc.2006.08.008

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Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Polyaniline/mesoporous silica hybrids were prepared by chemical modification with aniline and their capacitances were examined for application to electrode of electrochemical capacitor. The chemical modification was performed by two kinds of processes, polymer insertion into pores and in-situ polymerization within pores. In the case of the polymer insertion process, since the mean pore sizes of the hybrid did not change, polyaniline molecules were not inserted. On the other hand, in the case of the in-situ polymerization process, the mean pore sizes decreased from that of mesoporous silica, while the XRD patterns became broad. Therefore, aniline molecules polymerized in the inside of pores, however, the mesoporous silica collapsed in part. Maximum capacitance measured in 1 mol/l H2SO4 aqueous solution was around 226 F per unit mass of polyaniline.

DOI： 10.1007/s10934-005-3132-z

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The crystal structures of two PbSb2O6-type compounds containing titanium, CdTi2O4(OH)(2) and LaTiSbO6 were refined by X-ray powder diffraction data. For both compounds structure refinements with the space group P3 I m were successful and the R-factors were Rwp = 6.46% and R rho = 4.90% for CdTi2O4(OH)(2) and Rwp = 9.55% and Rp = 7.17% for LaTiSbO6. These crystal structures were the same as that of the typical PbSb2O6-type compound in spite of the existence of protons in the interlayer or two different metal ions in the layer. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.materresbull.2005.03.024

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DOI： 10.1016/j.ssi.2004.02.019

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Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

In the present paper, we report a novel hydrothermal synthesis process for the preparation of A-site deficient perovskite-type solid solution in (1 - x)BaTiO(3)(.)xLa(2/3)TiO(3) (X = 0.1 - 1.0). The synthesized (1 - x)BaTiO(3)(.)xLa(2/3)TiO(3) have been characterized by powder X-ray diffraction (XRD), ICP elemental analysis, infrared spectroscopy and scanning electron microscopy. The diffractions of samples with x less than or equal to 0.7 were well indexed as a cubic structure, which is the same as a cubic perovskite-type BaTiO3. In the compositions of x greater than or equal to 0.8, the crystal structure changes from the cubic to an orthorhombic one. The effect of hydrothermal conditions has also been examined. In this work, it was observed that the optimum ratios of KOH/Ti, La/Ti, and La/Ba were 90, 0.6x and 0.9(1 - x), respectively, and the optimum crystallization temperature was 240 - 260 degreesC. (C) 2002 Elsevier Science B.V. All rights reserved.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

A novel one-dimensional zirconium phosphate inorganic polymer, [NH4](3)[Zr(OH)(2)(PO4)(HPO4)] has been synthesized in (HOCH2CH2)(2)O medium with F- ions in presence, and structurally characterized. The compound consists of macroanionic chains of [ZrP2O10H3](3-) separated by NH4+ cations.

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The kinetics of mullite crystallization from Al2O3-SiO2 glasses with chemical compositions ranging from 15 to 50 mol% Al2O3 were investigated under non-isothermal conditions using DTA. The glasses were prepared by ultra-quenching of molten droplets formed at the tip of a sintered aluminosilicate rod by an infra-red imaging furnace quenched by a twin-roller system. All the samples showed an exothermic peak at about 1000 degreesC associated with mullitization. This crystallization temperature increased slightly with decreasing Al2O3 content. The exothermic peak split into two peaks at a glass composition of about 25 mol% Al2O3. This splitting is thought to be related to phase separation of the glass preceding mullitization. The activation energies for the nucleation-growth mechanism of mullitization, calculated by the Kissinger method, were 900-1300 kJ/mol, in good agreement with those for glass fibers obtained under isothermal conditions. (C) 2001 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0955-2219(01)00266-7

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Textures formed by phase separation and crystallization of Al2O3-SiO2 glasses with 15, 25 and 50 mol% Al2O3 compositions were investigated by small angle X-rap scattering (SAXS) and TEM. From the Pored analysis of the SAXS patterns, droplet structures were found in glasses with Ii and 50 mol% Al2O3 compositions, whereas an interconnected structure was formed by spinodal decomposition in the glass with 25 mol% Al2O3. In the initial-stage crystallization of mullite, nucleation was considered to occur in the Al2O3-rich regions. The crystallites of mullite were of similar size to the phase separated region. The relationship between the annealing time and the size of the interconnected texture formed by spinodal decomposition was analyzed using Cahn's theory, giving good agreement with the result obtained by the Pored method. The distance distribution of the phase separated grains was obtained from the radial distribution function calculated by Fourier transformation of the SAXS patterns. The calculated intergrain distances increased with increasing annealing time and were in good agreement with those obtained from TER I observation. (C) 2001 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0022-3093(01)00315-5

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A soft-solution process for in situ coating of faujasite type zeolite crystals on glass fibers was investigated. Commercial SiO2-Al2O3 glass fibers (SA fiber) and SiO2 glass fibers (SO fiber) were reacted at 60-150 degrees C for various times with NaOH solutions containing NaCl as a mineralizer. The surface of glass fibers was initially leached by the solution but after a certain time crystals of faujasite type zeolite precipitated on the fibers. Eventually the fiber surface was completely coated because of an increase in the concentrations of Si and Al in the solution due to dissolution of the fibers, especially the SO fibers. The important experimental parameters for formation of faujasite type zeolite were found to be the mixing ratio of SA fiber/SO fiber, the reaction time, NaOH concentration and the amount of added NaCl. The lattice constant of the resulting faujasite type zeolite identified it as zeolite Na-X with a Si/Al ratio of 1.28. (C) 2000 Elsevier Science B.V. All rights reserved.

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DOI： 10.1557/JMR.2000.0030

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1111/j.1151-2916.1999.tb02171.x

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：KLUWER ACADEMIC PUBL  

Porous mullite fibers were prepared by crystallization and selective leaching of Al2O3-SiO2 glass fibers using buffered HF-NH4F(BHF) aqueous solutions. The optimum concentration of BHF solution for selective leaching of the fibers was 0.9 mass% HF and 17.0 mass% NH4F. By firing at 1000-1300 degrees C, the glass fibers changed into composite texture of mullite and glassy phase. Since the pores in the fibers were formed by selective leaching of glassy phase among mullite grains, they were tunable by changing the firing conditions of fibers. Pore size of the samples changed from around 4 nm in the 1100 degrees C fired sample to 16 and 40 nm in the 1200 and 1300 degrees C fired samples, respectively. The highest specific surface area obtained was around 30 m(2)/g, when the fibers were heat treated at 1200 degrees C for 24 h and leached for 20 h in 0.9 mass% HF-17.0 mass% NH4F solution. From the thermal stability tests of the porous mullite fibers, its specific surface area was found to be maintained up to 1200-1300 degrees C.

DOI： 10.1023/A:1009679321570

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In-situ coating of zeolite Na-A crystals on Al(2)O(3)-SiO(2) glass fibers was investigated by a low temperature chemical process. The glass fibers were reacted with various concentrations of NaOH solutions at 60-110 degrees C for various times. The surface of glass fibers was first leached by the solution but crystals of zeolite Na-A precipitated on the glass fibers after a certain reaction time because the concentrations of Si and Al components in the solution increased by dissolution of the glass fibers. The precipitated zeolite was identified to be Na-A type but nosean-cancrinite-type phase and/or hydroxysodalite coexisted with zeolite Na-A at longer reaction times. With higher concentration of NaOH solution, the formation rate of zeolite Na-A was faster, the formation temperature was lower and the grain size was smaller ca. 2-3 mu m. Dense zeolite Na-A coatings were produced when the glass fibers were reacted in 4 M NaOH solution at 60 degrees C for 18 h. The amount of zeolite Na-A formed on the fibers was about 20 mass%.

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Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2019.3

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2019.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2019.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2019.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2019.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2019.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2019.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2019.1

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2018.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2018.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2018.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2018.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2018.9

Language：English   Presentation type：Poster presentation  

Event date： 2018.9

Language：English   Presentation type：Poster presentation  

Event date： 2018.9

Language：English   Presentation type：Poster presentation  

Event date： 2018.9

Language：English   Presentation type：Poster presentation  

Event date： 2018.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2018.9

Language：Japanese   Presentation type：Poster presentation  

Event date： 2018.9

Language：Japanese   Presentation type：Poster presentation  

Event date： 2018.9

Language：Japanese   Presentation type：Poster presentation  

Event date： 2018.6

Language：English   Presentation type：Oral presentation(invited, special)  

Venue：Ghent  

Event date： 2018.6

Language：English   Presentation type：Poster presentation  

Event date： 2018.6

Language：Japanese   Presentation type：Poster presentation  

Event date： 2018.6

Language：English   Presentation type：Poster presentation  

Event date： 2018.3

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2018.3

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2018.3

Language：English   Presentation type：Poster presentation  

Event date： 2018.3

Language：English   Presentation type：Poster presentation  

Event date： 2018.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2018.3

Language：English   Presentation type：Poster presentation  

Event date： 2018.3

Language：English   Presentation type：Poster presentation  

Event date： 2018.1

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2018.1

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2018.1

Language：English   Presentation type：Oral presentation(general)  

Event date： 2018.1

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2018.1

Language：English   Presentation type：Oral presentation(general)  

Event date： 2017.12

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Event date： 2017.11

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2017.11

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2017.10

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.10

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.10

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.10

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.10

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2017.9

Language：English   Presentation type：Poster presentation  

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2017.9

Language：English   Presentation type：Poster presentation  

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2017.9

Language：English   Presentation type：Poster presentation  

Venue：Budapest, Hungary  

Event date： 2017.9

Language：English   Presentation type：Poster presentation  

Venue：Budapest, Hungary  

Event date： 2017.9

Language：English   Presentation type：Poster presentation  

Venue：Budapest, Hungary  

Event date： 2017.9

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2017.8

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2017.8

Language：English   Presentation type：Poster presentation  

Venue：Yokohama  

Event date： 2017.8

Language：English   Presentation type：Poster presentation  

Venue：Yokohama  

Event date： 2017.7

Language：English   Presentation type：Poster presentation  

Event date： 2017.7

Language：English   Presentation type：Poster presentation  

Event date： 2017.7

Language：English   Presentation type：Poster presentation  

Event date： 2017.7

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.3

Language：English   Presentation type：Poster presentation  

Event date： 2017.3

Language：English   Presentation type：Poster presentation  

Event date： 2017.3

Language：English   Presentation type：Poster presentation  

Event date： 2017.3

Language：English   Presentation type：Oral presentation(general)  

Event date： 2017.3

Language：English   Presentation type：Poster presentation  

Event date： 2017.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2017.1

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2017.1

Language：English   Presentation type：Oral presentation(general)  

Event date： 2017.1

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2017.1

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2017.1

Language：English   Presentation type：Oral presentation(general)  

Event date： 2016.11

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2016.10

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2016.10

Language：Japanese   Presentation type：Poster presentation  

Event date： 2016.10

Language：English   Presentation type：Poster presentation  

Event date： 2016.10

Language：English   Presentation type：Poster presentation  

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2016.9

Language：English   Presentation type：Oral presentation(general)  

Event date： 2016.9

Language：English   Presentation type：Oral presentation(general)  

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2016.9

Language：English   Presentation type：Oral presentation(general)  

Event date： 2016.9

Language：English   Presentation type：Poster presentation  

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2016.6

Language：English   Presentation type：Oral presentation(general)  

Event date： 2016.3

Language：English   Presentation type：Oral presentation(general)  

Event date： 2016.3

Language：Japanese   Presentation type：Other  

Event date： 2016.3

Language：Japanese   Presentation type：Other