研究者詳細 - 中西　和樹

論文 - 中西　和樹

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Preparation of Hierarchically Porous Nanocrystalline CaTiO<sub>3</sub>, SrTiO<sub>3</sub> and BaTiO<sub>3</sub> Perovskite Monoliths 査読有り

Ruzimuradov, O; Hasegawa, G; Kanamori, K; Nakanishi, K

JOURNAL OF THE AMERICAN CERAMIC SOCIETY 94 巻 ( 10 ) 頁： 3335 - 3339 2011年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of the American Ceramic Society

Hierarchically porous nanocrystalline CaTiO3, SrTiO 3, and BaTiO3 ceramics have been produced by impregnating corresponding alkaline-earth metal ions into preformed macroporous TiO2 monoliths in a solution containing urea, followed by calcination. The macroporous TiO2 had been obtained via the sol-gel process accompanied by phase separation utilizing a chelating agent, ethyl acetylacetonate (EtAcAc), together with mineral salt and ammonium chloride, to decrease the reactivity of titanium alkoxide. Formations of CaCO3, SrCO3, and BaCO3 on the surface of TiO2 monoliths are promoted by CO2 generated by the concurrent two processes during impregnation; hydrolysis, and decarbonation of the chelating agent EtAcAc, and hydrolysis of urea at 60°C. The latter also raises pH of the impregnating solution which further promotes the mineralization of the carbonate salts. Calcination of the resultant monolithic composite of metal carbonate/TiO2 allows the crystallization of metal titanate. The addition of urea to the impregnating solution is found to be an effective strategy for the formation of perovskite monoliths by the impregnation process. This study provides a versatile approach to the preparation of hierarchically porous titania-based perovskites. © 2011 The American Ceramic Society.

DOI： 10.1111/j.1551-2916.2011.04613.x

Fabrication of highly crosslinked methacrylate-based polymer monoliths with well-defined macropores via living radical polymerization 査読有り

Hasegawa, G; Kanamori, K; Nakanishi, K; Yamago, S

POLYMER 52 巻 ( 21 ) 頁： 4644 - 4647 2011年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Polymer

Rigid methacrylate-based polymer monoliths with well-defined macropores have been synthesized from glycerol 1,3-dimethacrylate (GDMA) and trimethylolpropane trimethacrylate (Trim) by organotellurium-mediated living radical polymerization. In each system, poly(ethylene oxide) induced spinodal decomposition with the progress of polymerization of GDMA or Trim. Well-defined macroporous structure can be tailored by fixing the bicontinuous structure by the sol-gel transition. Both polymer monoliths possessed macropores with narrow size distributions and the macropore size can be controlled simply by varying the amount of poly(ethylene oxide). Starting from GDMA, polymer monoliths with unimodal macropores can be obtained due to the collapse of micro- and mesopores, which were originally embedded in macropore skeletons, by large shrinkage during drying. In contrast, starting from Trim, the obtained polymer monoliths include not only macropores but also micro- and mesopores, which lead to high specific surface area (470 m2 g-1), owing to the higher crosslinking density. © 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2011.08.028

Facile preparation of monolithic magnesium titanates with hierarchical porosity 査読有り

Ruzimuradov, ON; Hasegawa, G; Kanamori, K; Nakanishi, K

JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 119 巻 ( 1390 ) 頁： 440 - 444 2011年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of the Ceramic Society of Japan

In this study, we for the first time came up with a facile approach to fabricate hierarchically porous nano-crystalline monolithic magnesium titanates (MgTi2O5/MgTiO3) by impregnating magnesium chloride into hierarchically porous TiO2 monolith in a solution containing urea followed by appropriate heat-treatment. The formation of porous MgTi2O5/MgTiO3 monolithic materials took place by the solid-state reaction between original TiO2 networks and precipitated MgCO3. The MgCO3 is precipitated within the TiO2 wet gel by the reaction between impregnated Mg2+ and CO2, which is produced by hydrolysis and decarbonation of chelating agent in the TiO2 wet gels and by the hydrolysis of urea at 60°C. The resultant porous magnesium titanates retained narrow macropore size distribution centered at the diameter ̃1 μm. These porous monoliths produced by impregnation, a facile and the low-cost method, are expected to open various engineering applications owing to the low thermal expansion coefficients and high chemical and physical stabilities. © 2011 The Ceramic Society of Japan.

DOI： 10.2109/jcersj2.119.440

Performance evaluation of long monolithic silica capillary columns in gradient liquid chromatography using peptide mixtures 査読有り

Eghbali, H; Sandra, K; Detobel, F; Lynen, F; Nakanishi, K; Sandra, P; Desmet, G

JOURNAL OF CHROMATOGRAPHY A 1218 巻 ( 21 ) 頁： 3360 - 3366 2011年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Chromatography A

A systematic study is reported on the performance of long monolithic capillary columns in gradient mode. Using a commercial nano-LC system, reversed-phase peptide separations obtained through UV-detection were conducted. The chromatographic performance, in terms of conditional peak capacity and peak productivity, was investigated for different gradient times (varying between 90 and 1320min) and different column lengths (0.25, 1, 2 and 4m) all originating from a single 4m long column. Peak capacities reaching values up to n=103 were measured in case of the 4m long column demonstrating the high potential of these long monoliths for the analysis of complex biological mixtures, amongst others. In addition, it was found that the different column fragments displayed similar flow resistance as well as consistent chromatographic performance in accordance with chromatographic theory indicating that the chromatographic bed of the original 4m long column possessed a structural homogeneity over its entire length. © 2010 Elsevier B.V.

DOI： 10.1016/j.chroma.2010.10.045

Transition from transparent aerogels to hierarchically porous monoliths in polymethylsilsesquioxane sol-gel system 査読有り

Kanamori, K; Kodera, Y; Hayase, G; Nakanishi, K; Hanada, T

JOURNAL OF COLLOID AND INTERFACE SCIENCE 357 巻 ( 2 ) 頁： 336 - 344 2011年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Colloid and Interface Science

A transition from hierarchical pore structures (macro- and meso-pores) to uniform mesopores in monolithic polymethylsilsesquioxane (PMSQ, CH3SiO1.5) gels has been investigated using a sol-gel system containing surfactant Pluronic F127. The precursor methyltrimethoxysilane (MTMS) undergoes an acid/base two-step reaction, in which hydrolysis and polycondensation proceed in acidic and basic aqueous media, respectively, as a one-pot reaction. Porous morphology is controlled by changing the concentration of F127. Sufficient concentrations of F127 inhibit the occurrence of micrometer-scale phase separation (spinodal decomposition) of hydrophobic PMSQ condensates and lead to well-defined mesoporous transparent aerogels with high specific pore volume as a result of the colloidal network formation in a large amount of solvent. Phase separation regulates well-defined macropores in the micrometer range on decreasing concentrations of F127. In the PMSQ-rich gelling domain formed by phase separation, the PMSQ colloidal network formation forms mesopores, leading to monolithic PMSQ gels with hierarchical macro- and meso-pore structures. Mesopores in these gels do not collapse on evaporative drying owing to the flexible networks and repulsive interactions of methyl groups in PMSQ. © 2011 Elsevier Inc.

DOI： 10.1016/j.jcis.2011.02.027

Monolithic silica rod columns for high-efficiency reversed-phase liquid chromatography 査読有り

Miyazaki, S; Takahashi, M; Ohira, M; Terashima, H; Morisato, K; Nakanishi, K; Ikegami, T; Miyabe, K; Tanaka, N

JOURNAL OF CHROMATOGRAPHY A 1218 巻 ( 15 ) 頁： 1988 - 1994 2011年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Chromatography A

Chromatographic properties of a new type of monolithic silica rod columns were examined. Silica rod columns employed for the study were prepared from tetramethoxysilane, modified with octadecylsilyl moieties, and encased in a stainless-steel protective column with two polymer layers between the silica and the stainless-steel tubing. A 25cm column provided up to 45,000 theoretical plates for aromatic hydrocarbons, or a minimum plate height of about 5.5μm, at optimum linear velocity of ca. 2.3mm/s and back pressure of 7.5MPa in an acetonitrile-water (80/20, v/v) mobile phase at 40°C. The permeability of the column was similar to that of a column packed with 5μm particles, with K F about 2.4×10 -14m 2 (based on the superficial linear velocity of the mobile phase), while the plate height value equivalent to that of a column packed with 2.5μm particles. Generation of 80,000-120,000 theoretical plates was feasible with back pressure below 30MPa by employing two or three 25cm columns connected in series. The use of the long columns enabled facile generation of large numbers of theoretical plates in comparison with conventional monolithic silica columns or particulate columns. Kinetic plot analysis indicates that the monolithic columns operated at 30MPa can provide faster separations than a column packed with totally porous 3-μm particles operated at 40MPa in a range where the number of theoretical plates (N) is greater than 50,000. © 2010 Elsevier B.V.

DOI： 10.1016/j.chroma.2010.11.032

Synthesis of hierarchical macro/mesoporous dicalcium phosphate monolith via epoxide-mediated sol-gel reaction from ionic precursors 査読有り

Tokudome, Y; Miyasaka, A; Nakanishi, K; Hanada, T

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY 57 巻 ( 3 ) 頁： 269 - 278 2011年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Sol-Gel Science and Technology

Starting from calcium chloride dihydrate (CaCl2•2H 2O), phosphoric acid (H3PO4), and poly(acrylic acid) (PAA) dissolved in a mixture of water and methanol (MeOH), dicalcium phosphate anhydrous (DCPA, CaHPO4) monoliths with co-continuous macropores and mesopores have been synthesized by the addition of propylene oxide. Macropores are formed as a result of phase separation, while mesopores as interstices between primary particles with the size of ca. 30 nm. Propylene oxide acts as a proton scavenger and leads to moderate pH increase in a reaction solution, which brings about gelation in several minutes. On the other hand, PAA acts as a crystal growth inhibitor as well as a phase separation inducer. The extensive crystal growth of DCPA is hindered by the addition of PAA which allows morphological control of the structure in micrometer range. Fourier transform infrared spectroscopy indicates that PAA and DCPA form composite via interaction between the carboxyl groups and the surface of crystals, and together form gel phase. The solvent phase, which is converted to macropores after evaporative drying, is mainly comprised of solvent. The degree of supersaturation in a reaction solution considerably influence on the crystallization process, and thereby, influences on the porous structure in nano- and micrometer ranges. © 2010 Springer Science+Business Media, LLC.

DOI： 10.1007/s10971-010-2184-y

Microscopic Characterizations 査読有り

Haruko Saito, Kazuyoshi Kanamori, Kazuki Nakanishi

Monolithic Silicas in Separation Science: Concepts, Syntheses, Characterization, Modeling and Applications, First Edition 頁： 81 - 102 2011年1月

Synthesis Concepts and Preparation of Silica Monoliths 査読有り

Kazuki Nakanishi

Monolithic Silicas in Separation Science: Concepts, Syntheses, Characterization, Modeling and Applications, First Edition 頁： 11 - 33 2011年1月

(3-Mercaptopropyl)trimethoxysilane-derived Porous Gel Monolith via Thioacetal Reaction-Assisted Sol-Gel Route 査読有り

Ito S., Nishi M., Kanamori K., Nakanishi K., Kurahashi T., Matsubara S., Shimotsuma Y., Miura K., Hirao K.

3RD INTERNATIONAL CONGRESS ON CERAMICS (ICC): NOVEL CHEMICAL PROCESSING SOL-GEL AND SOLUTION-BASED PROCESSING 18 巻 ( SYMPOSIUM 2A ) 2011年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IOP Conference Series: Materials Science and Engineering

Porous gel monolith was synthesized by reacting (3-mercaptopropyl) trimethoxysilane (MPTMS) with acetone on acidic conditions. It is known that MPTMS itself is difficult to turn into gel on acidic conditions and instead oligomers are obtained owing to the large mercaptopropyl group. In our system, the gels were obtained since acetone worked as a cross-linker via thioacetal reaction. Additionally, Au ions were selectively adsorbed on the obtained gel. When an obtained white gel was soaked in a chloroauric acid solution, the gel turned brown and was getting dark depending on the soaked time; on the other hand, the color of the solution turned from yellow to colorless. © 2011 Ceramic Society of Japan.

DOI： 10.1088/1757-899X/18/3/032003

その他リンク： http://orcid.org/0000-0002-8069-4780

Pore Structure and Mechanical Properties of Poly(methylsilsesquioxane) Aerogels 査読有り

Kanamori K., Hayase G., Nakanishi K., Hanada T.

3RD INTERNATIONAL CONGRESS ON CERAMICS (ICC): NOVEL CHEMICAL PROCESSING SOL-GEL AND SOLUTION-BASED PROCESSING 18 巻 2011年

Hierarchically Porous Carbon Monoliths with High Surface Area from Bridged Poly(silsesquioxane) without Thermal Activation Process 査読有り

Hasegawa G., Kanamori K., Nakanishi K., Hanada T.

3RD INTERNATIONAL CONGRESS ON CERAMICS (ICC): NOVEL CHEMICAL PROCESSING SOL-GEL AND SOLUTION-BASED PROCESSING 18 巻 ( SYMPOSIUM 2A ) 2011年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IOP Conference Series: Materials Science and Engineering

Hierarchically porous carbon monoliths with high specific surface areas have been fabricated by removing nano-sized silica phase from carbon/silica composites pyrolyzed from bridged poly(silsesquioxane). This activation method improves the homogeneity between inner and outer parts of the monoliths compared to the conventional thermal activation methods. © 2011 Ceramic Society of Japan.

DOI： 10.1088/1757-899X/18/3/032005

その他リンク： http://orcid.org/0000-0002-8069-4780

Synthesis of new flexible aerogels from MTMS/DMDMS via ambient pressure drying 査読有り

Gen Hayase, Kazuyoshi Kanamori, Kazuki Nakanishi, Teiichi Hanada

IOP Conference Series: Materials Science and Engineering 18 巻頁： 032013 2011年

Monolithic electrode for electric double-layer capacitors based on macro/meso/microporous S-Containing activated carbon with high surface area 査読有り

Hasegawa, G; Aoki, M; Kanamori, K; Nakanishi, K; Hanada, T; Tadanaga, K

JOURNAL OF MATERIALS CHEMISTRY 21 巻 ( 7 ) 頁： 2060 - 2063 2011年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Materials Chemistry

Macro/meso/microporous carbon monoliths doped with sulfur have been prepared from sulfonated poly(divinylbenzene) networks followed by the activation with CO2 resulted in the activated carbon monoliths with high surface area of 2400 m2 g-1. The monolithic electrode of the activated carbon shows remarkably high specific capacitance (175 F g-1 at 5 mV s-1 and 206 F g-1 at 0.5 A g-1). © The Royal Society of Chemistry.

DOI： 10.1039/c0jm03793a

New flexible aerogels and xerogels derived from methyltrimethoxysilane/dimethyldimethoxysilane co-precursors 査読有り

Hayase, G; Kanamori, K; Nakanishi, K

JOURNAL OF MATERIALS CHEMISTRY 21 巻 ( 43 ) 頁： 17077 - 17079 2011年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Materials Chemistry

We report new flexible "marshmallow-like" aerogels and xerogels with a bendable feature from the methyltrimethoxysilane (MTMS) and dimethyldimethoxysilane (DMDMS) co-precursor systems. A 2-step acid/base sol-gel process and surfactant are employed to control the phase separation of the hydrophobic networks, which give porous monolithic gels. The obtained gels become softer and more flexible with increasing DMDMS fractions. © 2011 The Royal Society of Chemistry.

DOI： 10.1039/c1jm13664j

In situ SAXS observation on metal-salt-derived alumina sol-gel system accompanied by phase separation 査読有り

Tokudome, Y; Nakanishi, K; Kanamori, K; Hanada, T

JOURNAL OF COLLOID AND INTERFACE SCIENCE 352 巻 ( 2 ) 頁： 303 - 308 2010年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Colloid and Interface Science

The structure formation process of hierarchically porous alumina gels has been investigated by in situ small angle X-ray scattering (SAXS). The measurement was performed on the sol-gel solution containing aluminum chloride hexahydrate (AlCl3·6H2O), poly(ethylene oxide) (PEO), and propylene oxide (PO). The temporal divergence of scattering intensity in the low q regime was observed in the early stage of reaction, indicating that the occurrence of spinodal-decomposition-type phase separation. Detailed analysis of the SAXS profiles revealed that phase separation occurs between weakly branched polymerizing aluminum hydroxide (AH) and PEO. Further progress of the condensation reaction forms phase-separated two phases, that is, AH-rich phase and PEO-rich phase with the micrometer-range heterogeneity. The growth and aggregation of primary particles occurs in the phase-separated AH-rich domain, and therefore, the addition of PEO influences on the structure in nanometer regime as well as micrometer regime. The moderate stability of oligomeric species allows homogeneous condensation reaction parallel to phase separation and successful formation of hierarchically porous alumina gel. © 2010 Elsevier Inc.

DOI： 10.1016/j.jcis.2010.08.041

Synthesis of high-silica and low-silica zeolite monoliths with trimodal pores 査読有り

Tokudome, Y; Nakanishi, K; Kosaka, S; Kariya, A; Kaji, H; Hanada, T

MICROPOROUS AND MESOPOROUS MATERIALS 132 巻 ( 3 ) 頁： 538 - 542 2010年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Microporous and Mesoporous Materials

Using macroporous alumina as an aluminum source as well as structural support, high- and low-silica zeolites with trimodal pores have been fabricated in a monolithic form. Trimodally porous zeolites are obtained by the hydrothermal treatment of a monolithic alumina support impregnated with a mixture of AEROSIL 200, H2O, and sodium hydroxide or tetrapropylammonium hydroxide. The results of XRD measurement and 27Al NMR analysis reveal the formation of zeolites and the incorporation of Al into zeolite frameworks in tetrahedrally-coordinated environment. Low-silica zeolites, such as PHI- and ANA-type zeolites are formed when sodium hydroxide is utilized as a base and a structure directing agent (SDA). On the other hand, MFI-type zeolites are crystallized from highly supersaturated solutions with the use of tetrapropylammonium hydroxide. High alkaline resistance of alumina support enables the choice of wide range of OH-/SiO2 ratio, and moreover, the choice of desirable degree of supersaturation. As a result, the homogeneous crystallization of zeolites onto the alumina support has been successfully achieved. © 2010 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.micromeso.2010.04.005

Sol-gel preparation of Ni/TiO<sub>2</sub> catalysts with bimodal pore structures 査読有り

Numata, M; Takahashi, R; Yamada, I; Nakanishi, K; Sato, S

APPLIED CATALYSIS A-GENERAL 383 巻 ( 1-2 ) 頁： 66 - 72 2010年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Applied Catalysis A: General

Ni/TiO2 with bimodal pore structure was prepared from nickel nitrate and titanium alkoxide by a sol-gel process under acidic conditions in the presence of formamide. The Ni/TiO2 has continuous macropores which are formed by fixing the transitional structure of phase separation. Although the addition of nickel nitrate in the sol-gel reaction of titanium alkoxide steeply decreases the phase separation tendency, the macropore size can be controlled by changing the composition of preparation. The Ni/TiO 2 prepared by sol-gel has higher dispersion of Ni compared with that prepared by impregnation, and shows catalytic activity for the selective hydrogenation of crotonaldehyde: selectivity in the hydrogenation of C=C bond is much higher than that of C=O bond over sol-gel-derived Ni/TiO2. © 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.apcata.2010.05.025

Fabrication of activated carbons with well-defined macropores derived from sulfonated poly(divinylbenzene) networks 査読有り

Hasegawa, G; Kanamori, K; Nakanishi, K; Hanada, T

CARBON 48 巻 ( 6 ) 頁： 1757 - 1766 2010年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Carbon

Poly(divinylbenzene) (PDVB) monoliths with well-defined macropores that have been sulfonated and carbonized to obtain macroporous carbon monoliths. The original macroporous PDVB networks have been synthesized by living radical polymerization accompanied by spinodal decomposition. Sulfonation prevents polymer networks from large shrinkage and weight loss during carbonization by heat-treatment in an inert atmosphere. In the case of PDVB gels sulfonated at 120 °C using conc. H2SO4, mesopores in the original skeletons as well as macropores are retained after carbonization. The obtained carbon monoliths are subsequently activated by CO2, which resulted in activated carbons. The specific surface area of the obtained activated carbons reaches up to 2360 m2 g-1. © 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carbon.2010.01.019

その他リンク： http://orcid.org/0000-0002-8069-4780

A new route to monolithic macroporous SiC/C composites from biphenylene-bridged polysilsesquioxane gels 査読有り

Hasegawa G., Kanamori K., Nakanishi K., Hanada T.

Chemistry of Materials 22 巻 ( 8 ) 頁： 2541 - 2547 2010年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemistry of Materials

Macroporous polysilsesquioxane monoliths have been synthesized from biphenylene-bridged alkoxysilane via the sol-gel transition and concurrent phase separation both induced by the polycondensation reaction. The obtained polysilsesquioxane gels have been subsequently converted to macroporous SiC/C composites by the carbothermal reduction. The SiC/C monoliths thus obtained involve no visible cracks and their porosity reaches as high as >90%. In addition, according to the nitrogen adsorption-desorption measurement results, the micro- and mesopore characteristics of the samples did not undergo a significant change during the carbothermal reduction and the SiC/C composites have large specific surface areas owing to the microporous carbons in the skeletons. These composites therefore are more suitable for the applications to gas storage and catalyst supports compared to pure SiC. © 2010 American Chemical Society.

DOI： 10.1021/cm9034616

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