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Papers by Kazuki Nakanishi

Research paper thumbnail of Synthesis and electrochemical performance of hierarchically porous N-doped TiO2 for Li-ion batteries

New Journal of Chemistry, Mar 17, 2014

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Research paper thumbnail of Examination of Mesopore Structure of Hierarchically Macro/mesoporous Silica by Thermoporometry

MRS Proceedings, 2007

ABSTRACT Thermoporometry was employed to monitor the mesopore evolution in wet, drying and heat-t... more ABSTRACT Thermoporometry was employed to monitor the mesopore evolution in wet, drying and heat-treatment stages of monolithic macro/mesoporous silica with SBA-15 like structure. Direct comparison of mesopores in wet state was only possible with the samples extracted with sulfuric acid. In good agreement with the preceding study, the sulfuric acid not only removed the surfactant but also modified the silica gel network into that with reduced amount of micropores and increased stability against the drying stress. Thermoporometry revealed that the structural evolution takes place completely in the wet condition, which accompanies a decrease in the thickness of non-freezable water.

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Research paper thumbnail of Sol–gel synthesis of zinc ferrite-based xerogel monoliths with well-defined macropores

RSC Advances, 2013

ABSTRACT Starting from an aqueous solution, porous zinc ferrite-based xerogel monoliths have been... more ABSTRACT Starting from an aqueous solution, porous zinc ferrite-based xerogel monoliths have been prepared via a sol–gel route accompanied by phase separation mediated by propylene oxide in the presence of poly(acrylamide). The xerogels possess well-defined macropores, and the macroporous morphologies could be easily controlled (macropore size ranges from 0.55 to 1.29 μm) by simply changing the starting composition. As-dried xerogel samples were amorphous under X-ray diffraction, while heat-treatment in air brought about the formation of spinel type ferrite phase, ZnFe2O4. Calcination under Ar atmosphere allowed the crystallization of various iron-based phases/carbon composites (Fe3O4, Fe1-δO, Fe3N, Fe4N, Fe3C, and Fe). Samples heated under Ar flow exhibited hierarchical pore structures, including continuous macropores, in addition to mesopores and micropores embedded in the carbon-containing composite matrices.

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Research paper thumbnail of Elastic Aerogels and Xerogels Synthesized from Methyltrimethoxysilane (MTMS)

MRS Proceedings, 2008

ABSTRACT

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Research paper thumbnail of Water and Oil Repellent Soft, Porous Marshmallow-like Gel

Convertech E Print, Mar 1, 2014

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Research paper thumbnail of Crystalline ZrO2 Monoliths with Well-Defined Macropores and Mesostructured Skeletons Prepared by Combining the Alkoxy-Derived Sol-Gel Process Accompanied by Phase Separation and the Solvothermal Process

Chemistry of Materials, 2008

ABSTRACT

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Research paper thumbnail of Facile Preparation of Hierarchically Porous Ti02 Monoliths

Journal of the American Ceramic Society, 2010

ABSTRACT Monolithic titania (TiO2) with multiscale porous structures have been successfully prepa... more ABSTRACT Monolithic titania (TiO2) with multiscale porous structures have been successfully prepared via the sol–gel route accompanied by phase separation utilizing a chelating agent and mineral salt. The TiO2 gels obtained possess well-defined macropores derived from spinodal decomposition and mesopores as interstices of anatase TiO2 nanocrystallites. Most of the chelating agent were removed by hydrolysis and subsequent decarbonation through the gradual solvent exchange from ethanol to water. The TiO2 particles comprising TiO2 gel skeletons spontaneously converted from amorphous to anatase through the solvent exchange process in a mild condition at 60°C. The present method of the fabrication of porous TiO2 monoliths is advantageous for widespread applications because the reaction occurs under an almost neutral condition and does not require a hydrothermal process, which was indispensable to strengthen the monolith in the method previously reported.

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Research paper thumbnail of Octadecylsilylated Porous Silica Rods as Separation Media for Reversed-Phase Liquid Chromatography

Analytical Chemistry, Oct 1, 1996

Continuous porous silica rods consisting of a mesoporous (pore size, 14 or 25 nm) silica skeleton... more Continuous porous silica rods consisting of a mesoporous (pore size, 14 or 25 nm) silica skeleton of ∼1 μm size and through-pores of ∼1.7 μm were prepared and derivatized to C(18) phase by on-column reaction with octadecyldimethyl-(N,N-diethylamino)silane. The C(18) silica rods gave plate heights of 10-20 μm for aromatic hydrocarbons in 80% methanol and 20-40 μm for insulin in acetonitrile-water mixtures in the presence of trifluoroacetic acid. The performance of the silica rods was much better at a high flow rate than that of conventional columns packed with 5 μm C(18) silica particles having 12 and 30 nm pores, especially for high molecular weight species.

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Research paper thumbnail of A new hierarchically porous Pd@HSQ monolithic catalyst for Mizoroki–Heck cross-coupling reactions

New J Chem, Jan 6, 2014

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Research paper thumbnail of Size exclusion chromatography of standard polystyrenes with a wide range of molecular weight up to 7.45 x 106 on monolithic silica capillary columns

Polymer Journal, 2006

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Research paper thumbnail of Three-dimensional observation of macroporous silica gels and the study on structural formation mechanism

Colloids and Surfaces a Physicochemical and Engineering Aspects, Jun 1, 2007

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Research paper thumbnail of Sol-gel Synthesis of Macroporous YAG from Ionic Precursors via Phase Separation Route

Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi, 2007

ABSTRACT

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Research paper thumbnail of SilicaROD� � A new challenge in fast high-performance liquid chromatography separations

Trac, 1998

High performance liquid chromatography (HPLC) has become one of the most used methods for the ana... more High performance liquid chromatography (HPLC) has become one of the most used methods for the analysis of compound mixtures in industry, especially for the quality control of products. Nowadays productivity is the major and dominant upcoming issue, i.e. the goal is to drastically reduce the analysis time and cost per analysis. The solution of the task is higher throughput and faster HPLC methods. Here we describe a new monolithic type of HPLC column, the SilicaROD™ column, which permits the fast HPLC separation of compound mixtures within a few minutes.

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Research paper thumbnail of Chromatographic chip and method of fabrication thereof

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Research paper thumbnail of Synthesis of Hierarchically Porous HydrogenSilsesquioxane Monoliths and Embeddingof Metal Nanoparticles by On-Site Reduction

Advanced Functional Materials, Jun 6, 2013

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Research paper thumbnail of Facile Synthesis of Macroporous Cross-Linked Methacrylate Gels by Atom Transfer Radical Polymerization

Macromolecules, Oct 14, 2008

ABSTRACT

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Research paper thumbnail of Three-Dimensional Observation of Phase-Separated Silica-Based Gels Confined between Parallel Plates

Langmuir, Jul 1, 2003

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Research paper thumbnail of Phase Separation in Methylsiloxane Sol-Gel Systems in a Small Confined Space

Journal of Sol Gel Science and Technology, 2003

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Research paper thumbnail of Process for Producing Organic Porous Material and Organic Porous Column and Organic Porous Material

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Research paper thumbnail of Phase-Separation-Induced Titania Monoliths with Well-Defined Macropores and Mesostructured Framework from Colloid-Derived Sol−Gel Systems

Chem Mater, 2006

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Research paper thumbnail of Synthesis and electrochemical performance of hierarchically porous N-doped TiO2 for Li-ion batteries

New Journal of Chemistry, Mar 17, 2014

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Research paper thumbnail of Examination of Mesopore Structure of Hierarchically Macro/mesoporous Silica by Thermoporometry

MRS Proceedings, 2007

ABSTRACT Thermoporometry was employed to monitor the mesopore evolution in wet, drying and heat-t... more ABSTRACT Thermoporometry was employed to monitor the mesopore evolution in wet, drying and heat-treatment stages of monolithic macro/mesoporous silica with SBA-15 like structure. Direct comparison of mesopores in wet state was only possible with the samples extracted with sulfuric acid. In good agreement with the preceding study, the sulfuric acid not only removed the surfactant but also modified the silica gel network into that with reduced amount of micropores and increased stability against the drying stress. Thermoporometry revealed that the structural evolution takes place completely in the wet condition, which accompanies a decrease in the thickness of non-freezable water.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Sol–gel synthesis of zinc ferrite-based xerogel monoliths with well-defined macropores

RSC Advances, 2013

ABSTRACT Starting from an aqueous solution, porous zinc ferrite-based xerogel monoliths have been... more ABSTRACT Starting from an aqueous solution, porous zinc ferrite-based xerogel monoliths have been prepared via a sol–gel route accompanied by phase separation mediated by propylene oxide in the presence of poly(acrylamide). The xerogels possess well-defined macropores, and the macroporous morphologies could be easily controlled (macropore size ranges from 0.55 to 1.29 μm) by simply changing the starting composition. As-dried xerogel samples were amorphous under X-ray diffraction, while heat-treatment in air brought about the formation of spinel type ferrite phase, ZnFe2O4. Calcination under Ar atmosphere allowed the crystallization of various iron-based phases/carbon composites (Fe3O4, Fe1-δO, Fe3N, Fe4N, Fe3C, and Fe). Samples heated under Ar flow exhibited hierarchical pore structures, including continuous macropores, in addition to mesopores and micropores embedded in the carbon-containing composite matrices.

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Research paper thumbnail of Elastic Aerogels and Xerogels Synthesized from Methyltrimethoxysilane (MTMS)

MRS Proceedings, 2008

ABSTRACT

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Research paper thumbnail of Water and Oil Repellent Soft, Porous Marshmallow-like Gel

Convertech E Print, Mar 1, 2014

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Crystalline ZrO2 Monoliths with Well-Defined Macropores and Mesostructured Skeletons Prepared by Combining the Alkoxy-Derived Sol-Gel Process Accompanied by Phase Separation and the Solvothermal Process

Chemistry of Materials, 2008

ABSTRACT

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Facile Preparation of Hierarchically Porous Ti02 Monoliths

Journal of the American Ceramic Society, 2010

ABSTRACT Monolithic titania (TiO2) with multiscale porous structures have been successfully prepa... more ABSTRACT Monolithic titania (TiO2) with multiscale porous structures have been successfully prepared via the sol–gel route accompanied by phase separation utilizing a chelating agent and mineral salt. The TiO2 gels obtained possess well-defined macropores derived from spinodal decomposition and mesopores as interstices of anatase TiO2 nanocrystallites. Most of the chelating agent were removed by hydrolysis and subsequent decarbonation through the gradual solvent exchange from ethanol to water. The TiO2 particles comprising TiO2 gel skeletons spontaneously converted from amorphous to anatase through the solvent exchange process in a mild condition at 60°C. The present method of the fabrication of porous TiO2 monoliths is advantageous for widespread applications because the reaction occurs under an almost neutral condition and does not require a hydrothermal process, which was indispensable to strengthen the monolith in the method previously reported.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Octadecylsilylated Porous Silica Rods as Separation Media for Reversed-Phase Liquid Chromatography

Analytical Chemistry, Oct 1, 1996

Continuous porous silica rods consisting of a mesoporous (pore size, 14 or 25 nm) silica skeleton... more Continuous porous silica rods consisting of a mesoporous (pore size, 14 or 25 nm) silica skeleton of ∼1 μm size and through-pores of ∼1.7 μm were prepared and derivatized to C(18) phase by on-column reaction with octadecyldimethyl-(N,N-diethylamino)silane. The C(18) silica rods gave plate heights of 10-20 μm for aromatic hydrocarbons in 80% methanol and 20-40 μm for insulin in acetonitrile-water mixtures in the presence of trifluoroacetic acid. The performance of the silica rods was much better at a high flow rate than that of conventional columns packed with 5 μm C(18) silica particles having 12 and 30 nm pores, especially for high molecular weight species.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A new hierarchically porous Pd@HSQ monolithic catalyst for Mizoroki–Heck cross-coupling reactions

New J Chem, Jan 6, 2014

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Size exclusion chromatography of standard polystyrenes with a wide range of molecular weight up to 7.45 x 106 on monolithic silica capillary columns

Polymer Journal, 2006

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Three-dimensional observation of macroporous silica gels and the study on structural formation mechanism

Colloids and Surfaces a Physicochemical and Engineering Aspects, Jun 1, 2007

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Sol-gel Synthesis of Macroporous YAG from Ionic Precursors via Phase Separation Route

Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi, 2007

ABSTRACT

Bookmarks Related papers MentionsView impact

Research paper thumbnail of SilicaROD� � A new challenge in fast high-performance liquid chromatography separations

Trac, 1998

High performance liquid chromatography (HPLC) has become one of the most used methods for the ana... more High performance liquid chromatography (HPLC) has become one of the most used methods for the analysis of compound mixtures in industry, especially for the quality control of products. Nowadays productivity is the major and dominant upcoming issue, i.e. the goal is to drastically reduce the analysis time and cost per analysis. The solution of the task is higher throughput and faster HPLC methods. Here we describe a new monolithic type of HPLC column, the SilicaROD™ column, which permits the fast HPLC separation of compound mixtures within a few minutes.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Chromatographic chip and method of fabrication thereof

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Synthesis of Hierarchically Porous HydrogenSilsesquioxane Monoliths and Embeddingof Metal Nanoparticles by On-Site Reduction

Advanced Functional Materials, Jun 6, 2013

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Facile Synthesis of Macroporous Cross-Linked Methacrylate Gels by Atom Transfer Radical Polymerization

Macromolecules, Oct 14, 2008

ABSTRACT

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Three-Dimensional Observation of Phase-Separated Silica-Based Gels Confined between Parallel Plates

Langmuir, Jul 1, 2003

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Phase Separation in Methylsiloxane Sol-Gel Systems in a Small Confined Space

Journal of Sol Gel Science and Technology, 2003

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Process for Producing Organic Porous Material and Organic Porous Column and Organic Porous Material

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Phase-Separation-Induced Titania Monoliths with Well-Defined Macropores and Mesostructured Framework from Colloid-Derived Sol−Gel Systems

Chem Mater, 2006

Bookmarks Related papers MentionsView impact