論文 - 松根 英樹
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Synthesis and Characterization of Chitosan Cryogels Modified by Tripolyphosphate and Tannic Acid 査読あり 国際共著
Hardi, J., Kiyoyama, S., Matsune, H., & Shiomori, K.
Journal of Chemical Engineering of Japan 57 ( 1 ) 2024年8月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Takase H., Goya N., Kiyoyama S., Shiomori K., Matsune H.
Gels 10 ( 1 ) 2024年1月
掲載種別：研究論文（学術雑誌） 出版者・発行元：Gels
Hydrophobic cryogels with monolithic supermacropores based on poly-trimethylolpropane trimethacrylate (pTrim) containing 1-(2-Hydroxyl-5-nonyphenyl)ethanone oxime (LIX84-I) were successfully prepared by a cryo-polymerization technique using organic solvents with freezing points between room temperature and around 0 °C as solvents. The prepared cryogels were characterized in terms of macroscopic shape and porous structure. The cryogels had a monolithic supermacroporous structure and high contents of LIX84-I depending on the added amount of the extractant to the monomer solution. The amount of LIX84-I impregnated in the cryogel had a linear relationship with the added amount of LIX84-I in the monomer solution for cryo-polymerization. Cu(II) in the aqueous solution was immediately adsorbed into the cryogel containing LIX84-I.
DOI： 10.3390/gels10010009
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Synthesis of Silver Nanowires using N,N-Dimethylalkylamine 査読あり
Matsune H., Ueno Y., Wakamatsu T., Fujimoto M.A., Shiomori K., Yamamoto T., Kishida M.
Kagaku Kogaku Ronbunshu 50 ( 1 ) 27 - 34 2024年
掲載種別：研究論文（学術雑誌） 出版者・発行元：Kagaku Kogaku Ronbunshu
We report a novel method for the synthesis of silver nanowires (AgNWs). In this method, silver chloride (AgCl) and N,N-dimethyl-dodecylamine hydrochloride (C12H25NMe2·HCl) are used as a silver source and a protecting agent, respectively. Heating of both reagents in N,N-dimethyldodecylamine forms silver chlorocomplex, AgCl1‒nn solving homogeneously in the melting C12H25NMe2·HCl. The addition of the reducing agent, N,N-dibenzylhydroxyamine to the reaction mixture in order to reduce AgCl1‒nn to silver atom (Ag0) gives firstly multiplied twinned nanoparticles (MTPs), and then uniform silver nanowires (AgNWs) with the dimension of 50‒100 nm in thickness and >20 µm in length. Thermogravimetric analysis of the product reveals that highly pure AgNWs containing less organic residues are obtained. We investigate the effects of loading ratios of tertiary amine hydrochlorides to AgCl, the molecular structures of amines, and reaction temperature on the morphologies and yields of the generated AgNWs. We demonstrate that the MTPs are efficiently generated by the reduction reaction of AgCl1‒nn in the presence of tertiary amine hydrochlorides, and that tertiary amine hydrochlorides also play an important role in anisotropic crystal growth of Ag0 to AgNWs through the formation of the MTPs.
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Shiomori K., Matsune H., Inda N.I., Kiyoyama S., Takei T., Yoshida M.
AIP Conference Proceedings 2719 2023年5月
掲載種別：研究論文（学術雑誌） 出版者・発行元：AIP Conference Proceedings
Crosslinked-gel microcapsules immobilized small droplets of phenolic oxime extractant, 1-(2-hydroxy-5-nonylphenyl) ethanone oxime (LIX84-I) were prepared from O/W emulsion using falling-drop method followed by crosslinking of sodium alginate (Na-Alg) by Ca2+ ion and crosslinking of polyvinyl alcohol (PVA) by glutaraldehyde. A lot of fine droplets of LIX84-I were successfully immobilized in the microcapsules. The LIX84-I contents in the microcapsules increased with an increase in the LIX84-I amounts to the aqueous phase. The maximum extracted amounts of Cu(II) increased linearly with the LIX84-I contents with a slope of 1/2 which means two molecules of LIX84-I react with one Cu(II) ion. The extraction rate was not significantly affected by the size of the extractant droplets dispersed in the microcapsules. The microcapsules could be used repeatedly for the extraction and back-extraction of Cu(II).
DOI： 10.1063/5.0133362
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Batchuluun S., Matsune H., Shiomori K., Yasui K., Bayanjargal O.
AIP Conference Proceedings 2719 2023年5月
掲載種別：研究論文（学術雑誌） 出版者・発行元：AIP Conference Proceedings
In order to apply microcapsules as a functional material of cement composites, such as self-healing and heat-transfer-controlling materials, the effect of the addition of microcapsules on the mechanical properties of cement mortar was investigated. Polystyrene microcapsules containing CaCl2 aqueous solution as a microencapsulation substance with monocore and multicore structures were successfully prepared from solid-in-oil-in-water (S/O/W) emulsion by the solvent evaporation method. The compressive strengths of the mortars with and without the microcapsules were measured at various curing times. The compressive strength of the mortar without microcapsules increased with curing time. The compressive strength of the mortar with the microcapsules was lower than that without microcapsules and increased with time. The decrease in the compressive strength increased with the amount of the microcapsules added in the mortar. The self-healing effect of cracked mortar by CaCl2, which would be supplied from the microcapsules due to outer mechanical force making cracks in the mortar and on the microcapsules was not clearly shown in this experiment. However, permeation and leakage of Cl- ion to the surrounding mortar from the microcapsules was observed by mapping analysis of SEM-EDX.
DOI： 10.1063/5.0133363
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Takase H., Watanabe N., Shiomori K., Okamoto Y., Ciptawati E., Matsune H., Umakoshi H.
Colloids and Interfaces 7 ( 1 ) 2023年3月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Colloids and Interfaces
Here, we prepared hydrophobic cryogel particles with monolithic supermacropores based on poly-trimethylolpropane trimethacrylate (pTrim) by combining the inverse Leidenfrost effect and cryo-polymerization technique. The hydrophobic cryogel particles prepared by adopting this method demonstrated the separation of the stabilized O/W emulsion with surfactant. The prepared cryogel particles were characterized in terms of macroscopic shape and porous structure. It was found that the cryogel particles had a narrow size distribution and a monolithic supermacroporous structure. The hydrophobicity of the cryogel particles was confirmed by placing aqueous and organic droplets on the particles. Where the organic droplet was immediately adsorbed into the particles, the aqueous droplet remained on the surface of the particle due to repelling force. In addition, after it adsorbed the organic droplet the particle was observed, and the organic solvent was diffused into the entire particle. It was indicated that monolithic pores were distributed from the surface to the interior. Regarding the application of the hydrophobic cryogel particles, we demonstrated the separation of a stabilized oil-in-water emulsion, resulting in the successful removal of the organic solvent from the emulsion.
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Matsune H., Yoshida R., Ikemizu R., Shiomori K., Yamamoto T., Kishida M.
Chemistry Letters 52 ( 12 ) 870 - 873 2023年
掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
Colloidal nano-assemblies containing doxorubicin (DOX) are prepared for the first time by co-precipitation with gluconate. The spherical assembly is wrapped with a porous silica layer via sol-gel process, and confined in the formed cage by treatment with copper(II) ions (Cu2+). The reversible linking of DOX with Cu2+ is allowed to suppress the leakage of DOX, but quick release is turned on in response to glutathione (GSH). The synthesized stimulus-responsive nanocapsules are characterized, and examined in a release test with/without GSH and applied to living HeLa cells.
DOI： 10.1246/cl.230322
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Colloidal Trehalose Nanoparticles: Sacrifice Templates for Hollow Silica Nanospheres 査読あり
Yamamoto T., Matsune H., Ikemizu R., Shiomori K., Muraoka E., Kishida M.
Bulletin of the Chemical Society of Japan 96 ( 8 ) 813 - 815 2023年
掲載種別：研究論文（学術雑誌） 出版者・発行元：Bulletin of the Chemical Society of Japan
We demonstrate a trehalose nanoparticle (Tre NP) colloid first prepared by an injection method, and applied to a sacrifice template to create a hollow silica nanosphere. The Tre NP is successfully coated with a uniform layer of silica via sol-gel process, and removed simply by soaking in water, leading to the formation of the hollow nanostructure.
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Takase H., Shiomori K., Okamoto Y., Watanabe N., Matsune H., Umakoshi H.
ACS Applied Polymer Materials 4 ( 10 ) 7081 - 7089 2022年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：ACS Applied Polymer Materials
Here, we report a method to prepare cryogel particles with sponge-like mechanical properties, including high porosity and high elasticity. The preparation process of the cryogel particles of poly(2-hydroxythyl methacrylate) can be summarized in the two following steps: preparation of frozen droplets using the inverse Leidenfrost effect, followed by cryo-gelation by frozen polymerization. First, a polymer precursor was dropwise added into bulk liquid nitrogen (-196 °C). Then, frozen droplets were created by the inverse Leidenfrost effect, which were subsequently polymerized in liquid paraffine (-15 °C). After thawing and drying, the cryogel particles were obtained. The monolithic super-macroporous structure was observed by scanning electron microscopy (SEM). The mechanical properties of the cryogel particles were studied via compression-swelling tests. At maximum compression, the particles achieved 94.3% degree of deformation; remarkably, they returned to their original shape under the swelling state. The strategy proposed herein, which combines the inverse Leidenfrost effect with a cryo-polymerization technique, could be applied to prepare various polymer particles without employing surfactants.
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Preferential adsorption of L-tryptophan by L-phospholipid coated porous polymer particles 査読あり
Takase H., Suga K., Matsune H., Umakoshi H., Shiomori K.
Colloids and Surfaces B: Biointerfaces 216 2022年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Colloids and Surfaces B: Biointerfaces
Chiral selective adsorption of L-amino acid, tryptophan (Trp) was achieved using phospholipid membrane-coated porous polymer particles (PPPs). PPPs with numerous pores were prepared by in situ polymerization of divinylbenzene, and then coated with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC, L-phospholipid) via the impregnation method. Elemental mapping of energy dispersive X-ray (EDX) analysis revealed that DPPC molecules were distributed to the surface and the inner part of PPPs, where almost all the DPPC molecules applied for impregnation were deposited on PPPs. The phospholipid membrane properties of DPPC-PPPs were characterized using the fluorescence probe 6-lauroyl-2-dimethylaminonaphthalene (Laurdan). The results show that DPPC-PPPs possessed a lipid membrane-like environment similar to pure DPPC liposomes, especially at temperatures below 35 °C. DPPC-PPPs slightly adsorbed L-Trp and D-Trp at 45 °C, while DPPC-PPPs significantly adsorbed L-Trp but not D-Trp at 30 °C: enantio excess (e.e.) was 75.0%. The time course of Trp adsorption was investigated: for both enantiomers, similar adsorption behaviors were observed for 30 h, thus suggesting surface adsorption onto DPPC-PPPs. L-Trp adsorption continued after 30 h, suggesting that L-Trp could be distributed in the inner part of DPPC-PPPs. Interestingly, the reused DPPC-PPPs featured improved adsorption performance, suggesting that the deposited DPPC membranes on PPPs could act as chiral selectors for L-Trp. The optical resolution of L-/D-Trp was performed using DPPC-PPPs, resulting in the e.e. of D-Trp was > 60%. Thus, DPPC-PPPs have the potential of chiral selective adsorption of L-amino acid, which can be used as chiral separation materials.
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Takase H., Watanabe N., Shiomori K., Okamoto Y., Matsune H., Umakoshi H.
ACS Omega 8 ( 1 ) 829 - 834 2022年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：ACS Omega
We have investigated the versatility of a two-step preparation method, without a detergent, that combines both the inverse Leidenfrost effect and the cryogelation technique by using the macroporous particles of different kinds of monomers (four vinyl monomers) or a natural polymer (agarose). First, the precursor of polymers was dropped into liquid nitrogen to prepare the spherical frozen droplet by the inverse Leidenfrost effect. Second, the frozen droplets were cryo-polymerized at the frozen temperature; then, cryogel particles were prepared after thawing. Subsequently, the basic characteristics of the macroporous polymer particles obtained above were compared, focusing on the appearances, porous morphologies, and mechanical properties. It was found that the similar polymer particles could be obtained by the two-step preparation method, while there was a slight difference in their characteristics, depending on the type of monomers. Especially for the mechanical properties, the cryogel particles of the hydrophilic polymer exhibited a shape memory function with sponge-like elasticity, whereas the hydrophobic polymer particles were observed to be cracked after compression (i.e., no shape memory function). This work provides a versatile method of adopting various kinds of monomers and natural polymers for the preparation of macroporous particles. Hence, the method possibly has a potential to prepare and design "tailor-made"macroporous polymer particles for the application purpose.
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Batchuluun S., Yasui K., Matsune H., Shiomori K., Kiyoyama S., Bayanjargal O.
Journal of Chemical Engineering of Japan 55 ( 5 ) 217 - 224 2022年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Chemical Engineering of Japan
Polystyrene microcapsules were prepared by using the solvent evaporation method from S/O/W emulsion which contains fine particles of CaCl2 in the organic phase. The microcapsules were fractionated by their size and permeability of the wall using settling difference in methanol. Further, phase change materials that have two different wet-ability characters were successfully impregnated. The hydrophobic compound was easily impregnated to microcapsules which have hydrophobic wall material. Meanwhile, the hydrophilic compound, which is salt hydrate, was not impregnated to the same microcapsules via direct impregnation but the salt hydrate was successfully impregnated by the volatile exchange impregnation method. Simple thermal properties of the prepared phase change material microcapsules were examined by TGA and DSC methods.
DOI： 10.1252/jcej.21we120
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Enkhzaya S., Matsune H., Shiomori K., Oyuntstseg B.
AIP Conference Proceedings 2360 2021年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：AIP Conference Proceedings
This study examined the adsorption of heavy metals and precious metals from aqueous solution by livestock biomass as biosorbents and their treatment effect with reducing chemicals. The adsorption of copper, lead and cadmium was carried out using sheep wool, sheep manure and sheep fat. The copper adsorption was highest among three biosorbents. Sheep wool was treated with an aqueous solution of Na2S, NaOH, NaHSO3, and NaBH4 to enhance the adsorption ability. The Na2S treatment of sheep wool dramatically enhanced the adsorption amount of Au(III) and Cr(III) and was several effective for Cu(II) and Cr(IV). All adsorption results were confirmed with the Langmuir isotherm model in the equilibrium and Pseudo-second order model in the kinetics. From the adsorption properties and ESCA analysis of sheep wool adsorbed each metal, it was confirmed that Au(III) interacted with thiol and amino groups, Cu(II) and Cr(III) with a carboxyl group, and Cr(VI) with the amino group of sheep wool.
DOI： 10.1063/5.0059664
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Batchuluun S., Matsune H., Shiomori K., Bayanjargal O., Baasankhuu T.
Journal of Chemical Engineering of Japan 54 ( 9 ) 517 - 524 2021年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Chemical Engineering of Japan
Most microcapsule preparation methods produce a population of microcapsules in a bulk solution. To control the microcapsule preparation or obtain an optimal preparation condition, the mechanism of the microcapsule preparation should be investigated. The mechanism is estimated via structure reformation during the preparation process because diameter and wall thickness are drastically altered in the solution. Considering microcapsule applications, some important properties, such as the mechanical properties of microcapsules and release rate of the encapsulated product, depend on the microcapsule structure. In this study, polystyrene microcapsules containing saline water droplets were prepared via the solvent evaporation method from a solid-in-oil-in-water (S/O/W) emulsion system. The microcapsules exhibited a specific structural distribution, which comprised monocore, multicore, and solidcore structures. The structural distribution was altered by the preparation condition. The monocore structure was absolutely dominant owing to the increase in the amount of calcium chloride added in the organic phase. The salt concentration is not the sole controlling factor of the microcapsule structure, as the surfactant and dispersion exerted a significant impact on the microcapsule structure. The structural distribution was automatically analyzed by a machine learning algorithm (MLA). The decision-making time for the microcapsules preparation was shortened by the accelerated structure determination, and the accuracy was improved by increasing the number of counting particles.
DOI： 10.1252/jcej.21we052
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Analysis of the microcapsule structure based on machine learning algorithm 査読あり
Batchuluun S., Matsune H., Shiomori K., Bayanjargal O., Baasankhuu T.
Journal of Physics: Conference Series 1763 ( 1 ) 2021年2月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Physics: Conference Series
For the microcapsules preparation process, the mechanism is estimated by structure reformation during the preparation process since diameter and wall thickness drastically changed. Microstructures are recently studied by machine learning techniques. The Hough transformation algorithm is used by other researchers for the preparation of the microcapsules but it is difficult to determine the mechanism by using only a diameter change of the microcapsules. Therefore, one additional way to establish the mechanism is the analysis of the formation of the microcapsule structure. In this study, The Hough transformation algorithm was used for the image segmentation, the simple feature extractions were checked and the support vector machine and the k-nearest neighbors algorithm were used as classifiers in order to analyze the structure of the microcapsules which were prepared by solvent evaporation method from a solid in oil in water, S/O/W, emulsion system. The structural distribution was analyzed by the developed detection method. The microcapsules had a specific structural distribution which are monocore, multicore, and other aggregated structures. The structural distribution was changed by the preparation condition. The monocore structure was dominant by increasing in the amount of water soluble solid particles added in the organic phase.
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Chromium adsorption on sodium sulfide treated sheep wool 査読あり
Enkhzaya S., Matsune H., Shiomori K., Oyuntsetseg B.
Journal of Physics: Conference Series 1763 ( 1 ) 2021年2月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Physics: Conference Series
Chromium adsorption from the aqueous phase was evaluated using Mongolian sheep wool as a biosorbent. The wool was chemically treated with sodium sulfide to enhance the adsorption capacity. The surface of the wool was analyzed by SEM. EDX and FTIR were also used for the analysis of differences in the wool after chromium adsorption. Chromium was detected in the wool after adsorption by EDX analysis. FTIR data indicated the intensity change in amide A and amide I, which shows chromium may be adsorbed to the amino and carboxyl groups of the wool. The sodium sulfide treated wool showed better adsorption capacity of chromium(III) than the untreated wool. In the case of chromium(III), the adsorption amount increased with the pH increased, while for chromium(VI), the adsorption value increased with the pH decreased. Kinetic analysis of the adsorption indicated that the removal of chromium followed pseudo-second order kinetic model for the whole contact time range. Langmuir isotherm model was used for the analysis of adsorption equilibrium and the adsorption followed well Langmuir isotherm. This study demonstrates the sodium sulfide treated wool is an effective and low-cost biosorbent for heavy metal adsorption.
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Recent developments of microcapsules and polymer particles for separation medium 査読あり
Shiomori K., Matsune H., Kiyoyama S., Takei T., Yoshida M., Umakoshi H.
Journal of Physics: Conference Series 1763 ( 1 ) 2021年2月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Physics: Conference Series
Microcapsules and porous polymer particles containing extractants, which are functional molecules to extract target ions or molecules by specific interaction using in solvent extraction process, are expected to be an effective separation medium of various substances from aqueous solution in hydrometallurgical process of harmful or valuable metals and in environmental protection processes from various pollutants. The preparation method, encapsulating materials and application area of these materials has been developed and extended in recent years. Recent topics of this field was been presented. The research on the polymeric particles for separation medium investigated by authors was introduced and showed the structural effect of the polymeric particles containing extractant on the separation performance of metal ion and chiral separation of amino acids by porous particles impregnated with phospholipids.
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Recent developments of microcapsules and polymer particles for separation medium
Shiomori, K., Matsune, H., Kiyoyama, S., Takei, T., Yoshida, M., Umakoshi, H.
Journal of Physics: Conference Series 1763 2021年2月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Chromium adsorption on sodium sulfide treated sheep wool 査読あり
Enkhzaya S, Matsune H, Shiomori K., Oyuntsetseg B.
Journal of Physics: Conference Series 1763 2021年2月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Analysis of the microcapsule structure based on machine learning algorithm 査読あり
Batchuluun S., Matsune H., Shiomori K., Bayanjargal O., Baasankhuu T.
Journal of Physics: Conference Series 1763 ( 1,2 ) 2021年2月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Yamamoto T., Uchiyama S., Matsune H., Kishida M.
IOP Conference Series: Materials Science and Engineering 778 ( 1 ) 2020年4月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：IOP Conference Series: Materials Science and Engineering
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Yokoo K., Matsune H., Kishida M., Tatebayashi J., Yamamoto T.
Powder Technology 355 657 - 666 2019年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Powder Technology
© 2019 A fluidized bed type particulate matter (PM) removal device has been developed by focusing on the adhesion force under condition of non-water vapor. This device efficiently collects fine PM and can be operated as a low-temperature continuous regeneration device. The exhaust gas of a combustor includes water vapor at concentrations of 5–15 vol%. To further develop this device, the effect of water vapor on the continuous regeneration was investigated. The collection efficiency increases due to the water vapor. The reaction rate constant increases with increasing water vapor and with decreasing PM diameter. It is shown that water vapor promotes PM combustion at 250–400 °C. A smaller PM suits PM collection and combustion because smaller PM results in relatively larger adhesion force and well contacts the oxidant by dispersing it on the bed particles. The continuous regeneration temperature decreases to 380 °C due to the water vapor under optimal conditions.
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Anomalous heat effects induced by metal nano-composites and hydrogen gas 査読あり
Iwamura Y., Itoh T., Kasagi J., Kitamura A., Takahashi A., Takahashi K., Seto R., Hatano T., Hioki T., Motohiro T., Nakamura M., Uchimura M., Takahashi H., Sumitomo S., Furuyama Y., Kishida M., Matsune H.
Journal of Condensed Matter Nuclear Science 29 119 - 128 2019年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Condensed Matter Nuclear Science
© 2019 ISCMNS. All rights reserved. Collaborative research among Technova Inc., Nissan Motor Co. Ltd., Kobe Univ., Kyushu Univ., Nagoya Univ. and Tohoku Univ. was done from Oct. 2015 to Oct. 2017. For this collaborative work, a new accurate oil mass-flow calorimetry system was developed at Tohoku University to replicate anomalous heat generation experiments reported by Technova and the Kobe Univ. Group. In this paper, we present evidence of anomalous excess heat effects obtained from experiments at our laboratory at Tohoku University. Excess energy experiments were done using nano-sized metal composites with H2 or D2 gas. Anomalous excess heat generation were observed for all the samples at elevated temperature (150-350°C) except for the palladium nanoparticles embedded in mesoporous SiO2 (PSn1). The amount of anomalous heat generation per hydrogen atom ranged from 15 eV/H or D to 2.1 keV/H or D, which is too much to be explained by any known chemical process. Coincident burst events of pressure and gas temperature were observed for all the experiments using the CuNi7Zr15-Ox with H2 gas, which suggested sudden energy releases in the reaction chamber. These observations suggest large local energy bursts. Excess heat experiments using the same material at Kobe and Tohoku Universities showed similar experimental results. Qualitative reproducibility between the Kobe and Tohoku experiments was good.
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Matsune H., Ono T., Yoshida R., Yamamoto T., Kishida M.
Chemistry Letters 48 ( 9 ) 1058 - 1061 2019年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
© 2019 The Chemical Society of Japan A new class of nanoparticle (NP) is fabricated by cross-linking amino-functionalized silsesquioxane units with zinc ions via coordination bonds to create a drug delivery nanocarrier exhibiting rapid drug-release together with self-decomposition in response to glutathione (GSH). Regarding doxorubicin-loaded NPs, characterization of the nanostructures, their responsiveness to GSH and their cellular uptake by HeLa cells are examined.
DOI： 10.1246/cl.190353
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Yokoo K., Matsune H., Kishida M., Tatebayashi J., Yamamoto T.
Advanced Powder Technology 31 ( 2 ) 718 - 729 2019年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Advanced Powder Technology
© 2019 The Society of Powder Technology Japan The size of particulate matter (PM) generated by combustion has decreased with the improvement of combustion technology. While small PM has a significant negative impact on the human body, it is difficult for a conventional PM removal device to collect small PM. We developed a fluidized bed type PM removal device with a focusing adhesion force. This device collects small PM effectively and can be operated as a continuous regeneration device at low temperature. To further develop this device, it is important to investigate the PM combustion characteristics in this device. The kinetic model constructed in conventional thermogravimetry could not accurately represent the combustion rates of the solid fuel in the fluidized bed. Therefore, a new thermogravimetric apparatus was constructed in this study that generates the direct collision of air with carbon to reproduce the fluidized bed combustion. The influence of the relative velocity between PM and gas on the combustion rate was investigated. The effect of relative velocity was represented as the mass transfer coefficient of kinetic model. It is observed that the combustion rate shows Arrhenius behavior, and kinetic parameters were determined by fitting. The kinetic model was applied to the numerical simulations of the PM removal device. The numerical collection efficiency was in good agreement with the experimental data. PM adhesion and combustion characteristics were investigated in numerical simulations. It is observed that the adhesion rate is high at a low void fraction and that the combustion rate is high at a high relative velocity. The PM combustion amount is high for the high adhesion and combustion rates. The total combustion amount is determined to be 55% of the total amount of PM deposition after 180 min at each set of conditions.
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Excess heat evolution from nanocomposite samples under exposure to hydrogen isotope gases 査読あり
Kitamura A., Takahashi A., Takahashi K., Seto R., Hatano T., Iwamura Y., Itoh T., Kasagi J., Nakamura M., Uchimura M., Takahashi H., Sumitomo S., Hioki T., Motohiro T., Furuyama Y., Kishida M., Matsune H.
International Journal of Hydrogen Energy 43 ( 33 ) 16187 - 16200 2018年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：International Journal of Hydrogen Energy
© 2018 Hydrogen Energy Publications LLC Anomalous heat effect by interaction of hydrogen isotope gas and metal nanocomposites supported by zirconia or by silica has been examined. Observed absorption and heat evolution at RT were not too large to be explained by some chemical processes. At elevated temperatures of 200–300 °C, most samples with binary metal nanocomposites produced excess power of 3–24 W lasting for up to several weeks. The excess power was observed not only in the D-Pd·Ni system but also in the H–Pd·Ni system and H–Cu·Ni system, while single-element nanoparticle samples produced no excess power. The Pd/Ni ratio is one of the keys to increase the excess power. The maximum phase-averaged excess heat energy exceeded 270 keV/D, and the integrated excess heat energy reached 100 MJ/mol-M or 90 MJ/mol-H. It is impossible to attribute the excess heat energy to any chemical reaction; it is possibly due to radiation-free nuclear process.
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Effect of microwave attenuation in microwave plasma assisted combustion of biogas 査読あり
Yamamoto T., Uchiyama S., Matsune H., Kishida M.
23rd International Congress of Chemical and Process Engineering, CHISA 2018 and 21st Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction, PRES 2018 2 908 - 910 2018年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：23rd International Congress of Chemical and Process Engineering, CHISA 2018 and 21st Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction, PRES 2018
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Park K., Matsune H., Kishida M., Takenaka S.
International Journal of Hydrogen Energy 42 ( 30 ) 18951 - 18958 2017年7月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：International Journal of Hydrogen Energy
© 2017 Hydrogen Energy Publications LLC Carbon-supported Pd catalysts (Pd/CBs) for oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs) were modified with transition metals to enhance their catalytic activity. Pd-M/CB(N) (M = Co, Cu, Y, and Ag) was prepared by the reduction of metal precursors with NaBH4 in the presence of ethylene glycol (EG) without heat treatment. Pd-Ag/CB(N) showed the highest catalytic activity for the ORR among all the Pd-based catalysts tested in the present study, and it had twice higher activity than Pd/CB. The Pd-Ag/CB(N) also had the higher ORR activity than the Pd-Ag/CB prepared by a conventional impregnation method (Pd-Ag/CB(I)) due to the formation of smaller Pd-Ag alloy particles with 1–2 nm diameters. Pd-Ag/CB(N) was covered with silica layers (SiO2/Pd-Ag/CB(N)) in order to improve their durability under severe cathode conditions. The SiO2/Pd-Ag/CB(N) had high catalytic activity for the ORR during the durability test because silica layers prevented the diffusion of metal species from the catalysts.
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Reduction of selenate with hydrazine monohydrate over Pt catalysts in aqueous solution 査読あり
Zhao J., Matsune H., Takenaka S., Kishida M.
Chemical Engineering Journal 308 963 - 973 2017年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemical Engineering Journal
© 2016 Elsevier B.V. This paper describes the activity of Pt catalysts supported on metal-oxides (TiO2, ZrO2 and Al2O3) for the reduction reaction of selenate with hydrazine monohydrate in aqueous solution. The Pt/TiO2 catalyst exhibited superior performance in the reduction reaction of selenate with hydrazine monohydrate, compared with the Pt/ZrO2 and Pt/Al2O3 catalysts. The deactivation of Pt/TiO2 catalyst was attributed to the coverage of Pt particles by reduction product Se metal. To overcome this problem, a Pt catalyst supported on carbon nanotubes (CNTs) coated with TiO2 (TiO2/CNT) was also prepared. The selenate conversion over the Pt/TiO2/CNT catalyst was much higher than that over the Pt/TiO2 catalyst of the same Pt loading. Incorporating CNTs significantly improved the catalytic activity and durability of the Pt catalyst for the reduction of selenate.
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Yamamoto T., Uchiyama S., Matsune H., Kishida M.
11th Asia-Pacific Conference on Combustion, ASPACC 2017 2017-December 2017年
記述言語：日本語 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：11th Asia-Pacific Conference on Combustion, ASPACC 2017
© 2018 Combustion Institute. All Rights Reserved. To utilize biogas validly, we have applied plasma assisted combustion using microwave to the combustion and reformulation of biogas. In this study, the characteristics of combustion and reformulation of biogas have been investigated by comparing of large and small nozzle. In case of small nozzle, the combustion and reformulation of biogas stably occurs over a wider equivalence ratio area than that in case of large nozzle, because the damping of microwave is inhibited. N2and OH radical decrease, and H, CO, CH and C2radicals increase as equivalence ratio. H2and CO concentrations increase, and CO2concentration decreases with increasing equivalence ratio. In this method, since the reaction of CO2+ e → CO + O occurs, the amount of CO2of produced gas is less than the amount of supplied CO2in high equivalence ratio region. Cold gas efficiency increases with increasing H2and CO concentrations. When CH4is completely reformed into H2and CO, cold gas efficiency is about 95 %. However, the maximum value of cold gas efficiency is approximately 110 % at small nozzle, because CO2, which does not have calorific value, is decomposed into CO, which has calorific value.
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Modification of catalytic performance of supported Pt catalysts by coverage with silica layers 査読あり
Takenaka S., Akiyama R., Kim I., Matsune H., Kishida M.
Chemistry Letters 46 ( 6 ) 851 - 854 2017年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
© 2017 The Chemical Society of Japan. Supported Pt catalysts were covered with hydrophilic or hydrophobic silica layers. Both silica-coated Pt catalysts showed high tolerance to high-temperature sintering of Pt metal particles. The coverage with hydrophobic silica enhanced the activity of Pt catalysts for alkene hydrogenation in hydrophilic solvents.
DOI： 10.1246/cl.170194
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Zhao J., Matsune H., Takenaka S., Kishida M.
Chemical Engineering Journal 325 270 - 278 2017年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemical Engineering Journal
© 2017 Elsevier B.V. The pre-oxidation of arsenite (As(III)) to arsenate (As(V)) is a critical step for the removal of toxic arsenic in wastewater. In this work, a Pt catalyst supported on metal oxide was applied to the pre-oxidation step of As(III) without UV irradiation. It is demonstrated that Pt catalyst can effectively promote the oxidation of As(III) using oxygen at neutral pH due to the catalytic activity of Pt itself. The Pt/ZrO2 catalyst possessed excellent stability and could be used repeatedly with high catalytic performance. The oxidation rate of As(III) was structure-insensitive to Pt particle size and obeyed pseudo-first-order kinetics in As(III). The apparent activation energy was about 31.1 kJ/mol, which was obtained on the premise of order of 0.5 with respect to oxygen.
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Preparation of Metal Oxide Nanofilms Using Graphene Oxide as a Template 査読あり
Takenaka S., Miyake S., Uwai S., Matsune H., Kishida M.
Journal of Physical Chemistry C 119 ( 22 ) 12445 - 12454 2015年6月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Physical Chemistry C
© 2015 American Chemical Society. Two-dimensional (2D) materials have lately attracted significant attention, including nanosheets composed of metal oxide single crystallites that are typically prepared using a top-down synthesis method such as the exfoliation of layered metal oxides. In the present study, nanofilms composed of polycrystallites of metal oxides such as TiO<inf>2</inf>, ZrO<inf>2</inf>, Nb<inf>2</inf>O<inf>5</inf>, SnO<inf>2</inf>, and Ta<inf>2</inf>O<inf>5</inf> were prepared from the corresponding metal alkoxides using graphene oxide (GO) as a template, applying a bottom-up method. In this process, dried GO powder was dispersed in cyclohexane containing metal alkoxides and then treated at 453 K in an autoclave, such that the GO was converted into reduced GO (rGO) and metal oxide nanofilms were deposited on the rGO. Free-standing metal oxide nanofilms were subsequently obtained by calcination of the rGO/metal oxide composites in air at temperatures above 723 K. When dried GO was dispersed in cyclohexane containing metal alkoxides, the alkoxides adsorbed on the oxygen-containing functional groups of the GO were hydrolyzed by adsorbed or intercalated water in the dried GO and/or by water generated during the reduction of the GO, to form metal oxide nanofilms on the rGO. (Graph Presented).
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Takenaka S., Mikami D., Tanabe E., Matsune H., Kishida M.
Applied Catalysis A: General 492 60 - 67 2015年2月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Applied Catalysis A: General
© 2014 Elsevier B.V. All rights reserved. The surfaces of carbon nanotubes (CNTs) were covered with thin silica layers through the application of 3-aminopropyltriethoxysilane (APTES) in order to enhance the deposition of precious metal and transition metal oxide nanoparticles. Pt metal particles smaller than 2 nm in diameter could be deposited, using a conventional impregnation method, on CNTs coated with silica layers, whereas Pt particles supported on bare CNT surfaces were approximately 3 nm in diameter. Thus, coating CNTs with thin silica layers enhanced the catalytic activity of the Pt catalysts. In addition, CNTs with thin silica layers could be uniformly covered with transition metal oxide layers (ZrO2, Nb2O5 and Ta2O5) by hydrolysis of the corresponding metal alkoxides. In contrast, metal oxides were very difficult to deposit on bare CNTs. The thin silica layers produced on the CNTs via the use of APTES evidently function as adsorption sites for precursor metals and metal oxides, as well as nucleation sites for metals and metal oxides, allowing the formation of precious metal-CNT and transition metal oxide-CNT composites.
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Takenaka S., Miyazaki T., Matsune H., Kishida M.
Catalysis Science and Technology 5 ( 2 ) 1133 - 1142 2015年2月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Catalysis Science and Technology
© The Royal Society of Chemistry 2015. Carbon nanotube (CNT)-supported Pt catalysts (Pt/CNT) for use as cathode components in polymer electrolyte fuel cells (PEFCs) were covered with silica layers to prevent particle size increases during operation of the PEFC, either through the sintering of the Pt particles or the dissolution and redeposition of Pt ions. The formation of silica layers by the successive hydrolysis of 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS) significantly improved the durability of the Pt/CNT catalysts under cathodic conditions, although the activity of the silica-coated material for the oxygen reduction reaction was slightly lower than that of the uncoated catalyst. In contrast, a silica-coated Pt/CNT catalyst prepared by the successive hydrolysis of APTES and TEOS in the presence of NH2-(CH2)n-NH2(n = 6, 8 and 10) exhibited both high catalytic activity and excellent durability. The NH2-(CH2)n-NH2added during the silica coating process worked as a template for the formation of micropores in the silica layers and the resulting pore structures enhanced the diffusion of both reactants and products during oxygen reduction on the silica-coated Pt/CNT catalysts.
DOI： 10.1039/c4cy01301h
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Zhao J., Matsune H., Takenaka S., Kishida M.
Chemistry Letters 44 ( 11 ) 1563 - 1565 2015年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
© 2015 The Chemical Society of Japan. Although there has been no report on the catalytic reaction of selenate over heterogeneous catalysts in aqueous solution, we found that titania-supported Pt catalysts exhibited significantly high activity for the reduction of selenate with hydrazine. The Pt catalysts were deactivated during the reaction because of the deposition of Se metal, but showed excellent reusability. Therefore, it was firstly demonstrated that heterogeneous catalysts are effective for the removal of selenate from aqueous solution.
DOI： 10.1246/cl.150695
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Takenaka S., Miyamoto H., Utsunomiya Y., Matsune H., Kishida M.
Journal of Physical Chemistry C 118 ( 2 ) 774 - 783 2014年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Physical Chemistry C
Carbon nanotube-supported Pt catalysts (Pt/CNT) for the cathode in a polymer electrolyte fuel cell (PEFC) were covered with silica layers using tetraethoxysilane (TEOS) and also methyltriethoxysilane (MTEOS) to improve the catalyst durability under the severe conditions at the PEFC cathode. Both the silica-coated Pt/CNT catalysts had excellent durability for potential cycling between 0.6 and 1.0 V (vs RHE) in N2-purged 0.1 M HClO4 electrolyte, while Pt/CNT without silica coating was significantly deactivated due to an increase of the Pt metal particle size. Silica-coated Pt/CNT prepared from MTEOS had similar activity for the oxygen reduction reaction as Pt/CNT without silica coating, whereas the silica coverage obtained with TEOS slightly reduced the catalytic activity of the Pt/CNT catalyst. The silica layers prepared from MTEOS are more hydrophobic than those prepared from TEOS due to the presence of methyl groups. In addition, the silica layers prepared from MTEOS have larger pores than those prepared from TEOS. The hydrophobic silica layers with larger pores in the silica-coated Pt/CNT do not inhibit the diffusion of the reactants (oxygen) and the discharge of the products (water) during the oxygen reduction reaction. © 2013 American Chemical Society.
DOI： 10.1021/jp407928m
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Synthesis of silica-coated AgCl nanoparticles in aqueous poly(vinylpyrrolidone) solution 査読あり
Masuda K., Matsune H., Takenaka S., Kishida M.
Bulletin of the Chemical Society of Japan 87 ( 4 ) 573 - 575 2014年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Bulletin of the Chemical Society of Japan
Silica-coated AgCl nanoparticles are successfully prepared in an aqueous solution. AgCl nanoparticles are synthesized using poly(vinylpyrrolidone) as a protecting agent, and a silica layer is formed by hydrolysis and polycondensation of (3-aminopropyl)-triethoxysilane (APTS) and tetraethoxysilane. The results explain that APTS is a key material for the formation of the silica layer in the aqueous solution system. © 2014 The Chemical Society of Japan.
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Kurinobu S., Chigira O., Matsune K., Miura M., Naiem M.
Silvae Genetica 62 ( 1-2 ) 44 - 51 2013年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Silvae Genetica
Nine provenances of Albizia falcataria were planted at three square spacing levels (2, 3, and 4 m) in a split-plot design at Jember in East Java, Indonesia and measured annually for six years, which is three quarters of its rotation age. The effect of spacing on mean height development became progressively evident, due to the decline in growth at closer spacing caused by intensified competition, in six provenances, i.e., three provenances each from Java and East Indonesia, which were considered better adapted to the site because of their better growth and higher survival. On the contrary, the height growth curves of two provenances from New Guinea were almost identical, irrespective of spacing, indicating a lack of plasticity to the favorable environment at wider spacing. Dominant height was defined as the average of the five tallest trees per sub-plot (350 stems/ha), the growth curves at the three spacing levels were similar in the above-mentioned six provenances and were regarded as a single curve according to AIC-values. In contrast, dominant height growth curves of the New Guinea provenances were differentiated in the order of 2, 3, and 4 m spacing, approximately proportional to the intensity of choosing dominant trees per sub-plot. These results suggest that provenance variation exists for mean and dominant height and their response to different spacing. The cause of this variation was presumably attributable to the difference in competitive ability as well as the plasticity to the given environment. The use of dominant height for growth modeling of A. falcataria was found to be the most suitable for the adapted provenances.
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Bottom-up synthesis of titania and zirconia nanosheets and their composites with graphene 査読あり
Takenaka S., Uwai S., Ida S., Matsune H., Kishida M.
Chemistry Letters 42 ( 10 ) 1188 - 1190 2013年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
Simple impregnation of graphene oxide (GO) in cyclohexane containing Ti(OC4H9)4 or Zr(OC4H 9)4, followed by a solvothermal reaction, resulted in the deposition of nanosheets of TiO2 or ZrO2 a few nanometers thick on the reduced GO. In addition, free-standing nanosheets of TiO 2 or ZrO2 were formed by calcination of these composites in air. © 2013 The Chemical Society of Japan.
DOI： 10.1246/cl.130587
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Takenaka S., Tsukamoto T., Matsune H., Kishida M.
Catalysis Science and Technology 3 ( 10 ) 2723 - 2731 2013年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Catalysis Science and Technology
Carbon nanotube-supported Pd catalysts (Pd/CNT) as the cathode for polymer electrolyte fuel cells (PEFCs) were modified with various transition metals (Fe, Co, Ni and Cu) to improve their catalytic activity for the oxygen reduction reaction (ORR). Modification with these transition metals enhanced the activity of Pd/CNT for the ORR, especially the activity of Pd-Co/CNT, which was 2 times higher than that of Pd/CNT. X-ray diffraction and X-ray absorption spectroscopy indicated that the metal species in Pd-Co/CNT was mainly present as a Pd-Co alloy, which acts as catalytically active sites for the ORR. However, the Pd-Co/CNT catalysts were rapidly deactivated for the ORR in 0.1 M HClO 4 electrolyte due to the dissolution and diffusion of metal species out of the catalysts. Pd-Co/CNT was covered with silica layers with a thickness of a few nanometers, which prevented the diffusion of Co and Pd species into the HClO4 electrolyte. Thus, silica-coated Pd-Co/CNT catalysts exhibited high activity for the ORR and excellent durability under severe cathode conditions. © 2013 The Royal Society of Chemistry.
DOI： 10.1039/c3cy00446e
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Takenaka S., Iga A., Park K., Tanabe E., Matsune H., Kishida M.
Applied Catalysis A: General 450 211 - 221 2013年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Applied Catalysis A: General
Fishbone-typed carbon nanofibers (CNFs) that were formed by methane decomposition over silica-supported Ni catalysts were used as catalytic supports for Pt or Pt-Co alloy nanoparticles. The treatment of CNFs with concentrated HNO3 led to the formation of porous structures as well as to the introduction of oxygen-containing functional groups. Pt metal particles of a few nanometers in diameter could be stabilized on the CNFs treated with HNO 3 and showed a high tolerance to sintering at high temperatures, whereas Pt metal particles supported on the CNFs without any treatment were seriously aggregated at high temperatures. The porous structures and functional groups in the CNFs worked as anchoring sites for Pt metal nanoparticles. Thus, Pt-Co alloy particles of a few nanometers in diameter could be prepared by using the CNF support since the CNFs inhibited the sintering of the alloy particles during the treatment at high temperatures to allow for alloy formation. © 2012 Elsevier B.V.
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Takenaka S., Miyata H., Tsukamoto T., Matsune H., Kishida M.
ECS Transactions 50 ( 2 ) 1715 - 1722 2012年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：ECS Transactions
We have previously demonstrated that silica-coated Pd cathode catalysts show high durability under severe cathode conditions in polymer electrolyte fuel cells (PEFCs), while Pd catalysts without silica-coating seriously deactivate under the same conditions due to the dissolution of Pd metal. However, the activity of silica-coated Pd catalysts for the oxygen reduction reaction (ORR) was inferior to that of Pt catalysts used in state of the art PEFCs. In the present study, the ORR activity of Pd catalysts was improved by addition of Cu. Cu-added Pd catalyst prepared with a conventional impregnation method using mixed aqueous solutions of PdCl2 and Cu(NO3)2 had an ORR activity twice that of Pd catalysts. XRD and XAFS studies showed alloy formation between Pd and Cu. Thus, Pd-Cu alloys showed higher activity for the ORR compared with Pd metal. © The Electrochemical Society.
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Takenaka S., Arike T., Matsune H., Kishida M.
Applied Catalysis B: Environmental 125 358 - 366 2012年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Applied Catalysis B: Environmental
TiO 2 nanoparticles were deposited on carbon nanotubes (CNTs) to improve their photocatalytic activity. The outer surface of the CNTs could be uniformly covered with TiO 2 nanoparticles using the hydrolysis of titanium tetraisopropoxide (Ti(O iPr) 4) in the presence of urea or glycine amide. The urea and glycine amide acted as linker molecules between the TiO 2 nanoparticles and the CNT surfaces. The TiO 2-coated CNTs showed a higher catalytic activity for the photodegradation of organic molecules than TiO 2 alone. The addition of the CNTs to the TiO 2 photocatalytic system retarded the recombination of the electron-hole pairs generated in the photo-irradiated TiO 2. When Pt metal particles were inserted in the cavities of the CNTs in the TiO 2-coated CNT catalyst system, further improvements in the photocatalytic activity were observed. The TiO 2-coated CNTs with Pt metal particles displayed a unique catalytic performance in the photocatalytic degradation of organic impurities in water. © 2012 Elsevier B.V.
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Mardwita, Matsune H., Takenaka S., Kishida M.
Journal of Chemical Engineering of Japan 45 ( 7 ) 493 - 497 2012年7月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Chemical Engineering of Japan
We investigated the addition of chromium to alumina-supported Pt catalysts and its effect on catalytic activity in methane combustion. The Pt and Cr binary alumina-supported catalysts exhibited much higher activity than those without Cr. Alumina-supported Cr catalysts contain two chromium species, Cr 3+ and Cr 6+. From XPS analysis, it was found that more Cr 6+ species existed in the binary catalysts than in the single alumina-supported Cr catalysts. Pt species in the binary catalysts may promote Cr oxidation. Since Cr 6+ species are known to be more active than Cr3ff species in oxidation reactions, the increase in Cr 6+ in the binary catalysts may contribute to their higher activity compared with the Pt/Al 2O 3 catalyst. © 2012 The Society of Chemical Engineers, Japan.
DOI： 10.1252/jcej.12we025
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Takenaka S., Arike T., Miyazaki T., Matsune H., Kishida M.
Chemistry Letters 41 ( 6 ) 617 - 619 2012年6月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
TiO 2 nanoparticles were deposited on carbon nanotubes (CNTs) for improvement of their photocatalytic activity. CNTs could be uniformly covered with TiO 2 nanoparticles by the hydrolysis of titanium tetraisopropoxide in the presence of urea. Urea worked as linker molecules between the CNT surface and the TiO 2 nanoparticles. The resultant TiO 2CNT composites showed a high catalytic activity for photodegradation of organic molecules. © 2012 The Chemical Society of Japan.
DOI： 10.1246/cl.2012.617
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Takenaka S., Matsumori H., Matsune H., Kishida M.
Applied Catalysis A: General 409-410 248 - 256 2011年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Applied Catalysis A: General
Carbon black-supported Pt (Pt/CB) catalysts that have been used at the cathode in state of the art polymer electrolyte fuel cell (PEFC) were covered with silica layers to improve the durability of the Pt catalysts under PEFC cathode conditions. The durability of silica-coated Pt/CB to potential cycling between 0.6 and 0.9 V (vs. reversible hydrogen electrode (RHE)) was strongly dependent on the thickness of the silica layers, i.e., the durability of Pt/CB improved after coverage with thick silica layers. However, the coverage of the whole surface of the Pt/CB catalysts with silica layers produced electrochemically inactive Pt catalysts. Silica-coated Pt/CB catalysts with an optimal silica layer thickness showed similar activity for the oxygen reduction reaction compared to Pt/CB catalysts without a silica coating, and they had excellent durability at the cathode in a PEFC single cell. Coverage with silica layers improved the durability of the Pt/CB cathode catalysts without a decrease in the catalytic activity for the oxygen reduction reaction. © 2011 Elsevier B.V. All rights reserved.
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Takenaka S., Miyamoto H., Susuki N., Matsune H., Kishida M.
ECS Transactions 41 ( 1 ) 2305 - 2312 2011年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：ECS Transactions
Carbon nanotube-supported Pd catalyst (Pd/CNT) was covered with silica layers a few nanometers thick by successive hydrolysis of 3- aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS) to improve the durability of the Pd catalyst under cathode conditions of polymer electrolyte fuel cells (PEFCs). The coverage with silica layers resulted in the improvement of durability of Pd/CNT during the potential cycling between 0.05 and 1.20 V (vs. RHE) in aqueous HClO 4 electrolyte. The catalytic activity and durability of silica-coated Pd/CNT strongly depended on silica layer thickness in the catalysts. The coverage with thicker silica layers improved the durability of Pd/CNT but the catalytic activity of the catalysts for the oxygen reduction reaction became lower with silica layer thickness. The coverage of Pd/CNT with silica layers of ca. 3 nm thickness is preferable from a viewpoint of the catalytic activity and durability. © 2011 ECS - The Electrochemical Society.
DOI： 10.1149/1.3635764
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Catalytic performance of pt metal particles at the tips of carbon nanotubes 査読あり
Takenaka S., Iguchi T., Tanabe E., Matsune H., Kishida M.
Catalysis Letters 141 ( 6 ) 821 - 825 2011年6月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Catalysis Letters
The catalytic performance of Pt metal at the tips of carbon nanotubes (CNT@Pt), which was prepared by ethylene decomposition over Pt/MgO, was compared with that of Pt metal on the outer surface of CNT (Pt/CNT). CNT@Pt showed excellent catalytic performance toward the hydrogenation of α, β-unsaturated aldehydes to unsaturated alcohols, which was similar to that of Pt/CNT and resulted from a strong interaction between Pt metal and the CNT. Graphical Abstract: Pt metal particles at the tips of CNTs showed excellent activity for the selective hydrogenation of α, β-unsaturated aldehydes to unsaturated alcohols similarly to Pt metal particles supported on the outer surface of CNTs.[Figure not available: see fulltext.] © 2011 Springer Science+Business Media, LLC.
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Takenaka S., Susuki N., Miyamoto H., Tanabe E., Matsune H., Kishida M.
Journal of Catalysis 279 ( 2 ) 381 - 388 2011年4月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Catalysis
Pd metal supported on carbon nanotubes (Pd/CNT) for use as a cathode catalyst in polymer electrolyte fuel cells was covered with silica layers a few nanometers thick to improve the durability of the catalyst under severe cathode conditions. The silica-coated Pd/CNT cathode catalyst showed similar activity for the oxygen reduction to Pd/CNT despite coverage of the Pd metal with a silica insulator. In addition, the silica-coated Pd/CNT was highly durable during potential cycling between 0.05 and 1.20 V (vs. reversible hydrogen electrode) in aqueous HClO4 while Pd/CNT suffered serious deactivation under the same conditions. The silica layers in the silica-coated Pd/CNT prevent the diffusion of dissolved Pd species from the Pd metal out of the layers. Therefore, silica-coated Pd/CNT was highly durable under the cathode conditions. Furthermore, coverage of Pd/CNT with silica layers inhibited the two-electron reduction of oxygen to H2O2. © 2011 Elsevier Inc. All rights reserved.
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Takenaka S., Susuki N., Miyamoto H., Tanabe E., Matsune H., Kishida M.
Chemical Communications 46 ( 47 ) 8950 - 8952 2010年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemical Communications
Pd cathode catalysts for polymer electrolyte fuel cells have been covered with silica layers a few nanometres thick. The silica-coated Pd catalysts showed high activity and excellent durability for the oxygen reduction under the severe cathode conditions of PEFCs, while Pd catalysts without silica-coating were seriously deactivated under the same conditions. The coverage of Pd metal with silica prevents the diffusion of Pd species out of the silica layers. © 2010 The Royal Society of Chemistry.
DOI： 10.1039/c0cc04055j
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Takenaka S., Hirata A., Tanabe E., Matsune H., Kishida M.
Journal of Catalysis 274 ( 2 ) 228 - 238 2010年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Catalysis
Pt-based alloy catalysts such as carbon black-supported Pt-Co catalysts (Pt-Co/CB) are used in the oxygen reduction reaction in polymer-electrolyte fuel cells (PEFCs) and are generally treated at high temperatures to allow for alloy formation. However, treatment of these catalysts at high temperatures results in serious aggregation of alloy particles. In this study, a Pt-Co/CB catalyst was covered with silica layers to inhibit the aggregation of alloy particles during treatment of the catalyst at high temperature for alloy formation. Coverage of Pt-Co/CB with silica promoted Pt-Co alloy formation with a high alloying degree and a small particle size, whereas the alloying degree of Pt-Co alloys in Pt-Co/CB without silica-coating was low, and these alloy particles were seriously aggregated during treatment at high temperature. These silica-coated Pt-Co/CB catalysts showed high activity and excellent durability for the oxygen reduction reaction. © 2010 Elsevier Inc. All rights reserved.
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Arike T., Takenaka S., Matsune H., Kishida M.
Bulletin of the Chemical Society of Japan 83 ( 8 ) 953 - 959 2010年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Bulletin of the Chemical Society of Japan
Carbon nanotube-supported Ru (Ru/CNT) catalysts were covered with silica layers to inhibit the aggregation of Ru particles as well as the detachment of Ru particles from the CNTs during catalytic reactions. Coverage of the Ru/CNT with silica was performed by the successive hydrolysis of 3- aminopropyltriethoxysilane and tetraethoxysilane in the presence of CNT-supported Ru metal precursors, followed by reduction with hydrogen at 623 K. The diameter of the Ru particles in the silica-coated Ru/CNT ranged from 1 to 3 nm. The Ru particles and the CNTs in the silica-coated catalysts were uniformly covered with silica layers a few nanometers thick. The size of the Ru particles in the silica-coated catalysts did not change appreciably after treatment at 873 K, while the metal particles in the Ru/CNT were seriously aggregated after treatment at 873 K. The silica-coated Ru/CNT catalyzed the CO hydrogenation and the 1-hexene hydrogenation, despite the coverage of Ru particles with silica. In addition, the silica-coated Ru catalysts showed high durability toward Ru detachment from the CNTs during the repeated hydrogenation of 1-hexene, whereas the catalysts without silica layers were deactivated because of Ru detachment. Therefore, coverage of the Ru/CNT catalysts with silica layers prevented the deactivation of the catalysts. © 2010 The Chemical Society of Japan.
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Chemical synthesis of silver nanowires using N,N-dimethyldodecylamine oxide 査読あり
Matsune H., Kuramitsu Y., Takenaka S., Kishida M.
Chemistry Letters 39 ( 7 ) 717 - 719 2010年7月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
This paper describes a new approach for the synthesis of uniform silver nanowires (AgNWs) using zwitterionic amphiphile, N,N-dimethyldodecylamine oxide (DDAO). Heating of AgCl and DDAO in the presence of silver nanoparticles at 135°C for 3 h produces longer AgNWs. The DDAO serves as a source of both a reducing and capping agent in the process. © 2010 The Chemical Society of Japan.
DOI： 10.1246/cl.2010.717
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Takenaka S., Hirata A., Matsune H., Kishida M.
Chemistry Letters 39 ( 5 ) 458 - 459 2010年5月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
Carbon-supported Pt-Co catalyst for the oxygen reduction reaction was covered with silica layers to inhibit sintering of the metal particles. Coverage of the Pt-Co catalyst with silica layers promoted the formation of alloys with small diameters during treatment at 973 K. The silica-coated Pt-Co electrocatalyst showed a large electrochemically active surface area (ECSA) and excellent durability. © 2010 The Chemical Society of Japan.
DOI： 10.1246/cl.2010.458
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Matsumori H., Takenaka S., Matsune H., Kishida M.
Applied Catalysis A: General 373 ( 1-2 ) 176 - 185 2010年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Applied Catalysis A: General
Multi-walled carbon nanotube-supported Pt metal particle (Pt/CNT) catalysts were covered with silica layers with different thickness and density. In the present study, the Pt/CNT covered with silica layers (SiO2/Pt/CNT) was prepared by the successive hydrolysis of 3-aminopropyl-triethoxysilane (APTS) and tetraethoxysilane (TEOS). The thickness of silica layers in SiO2/Pt/CNT could be controlled by varying the concentration of silica sources during the preparation of SiO2/Pt/CNT. The density of silica layers in SiO2/Pt/CNT was changed by varying the treatment temperature for the catalysts as well as by adjusting the pH for the hydrolysis of silica sources during the preparation of the catalysts. The catalytic performance of these SiO2/Pt/CNT as cathode catalysts in polymer electrolyte fuel cells was examined. Pt/CNT covered with silica layers of adequate thickness (ca. 6 nm) and high density had a high electrochemically active surface area as well as excellent durability. Dense silica layers in SiO2/Pt/CNT prevented the diffusion of cationic Pt species dissolved from Pt metal particles out of the catalysts. © 2009 Elsevier B.V. All rights reserved.
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Nakagawa K., Takenaka S., Matsune H., Kishida M.
Studies in Surface Science and Catalysis 175 793 - 796 2010年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Studies in Surface Science and Catalysis
Silica-coated Pt-Ni alloys were prepared using a water-in-oil-type microemulsion. The silica-coated Pt-Ni alloys prepared without thermal treatment decomposed ethylene to form nanocomposites of carbon nanoflbers. © 2010 Elsevier B.V. All rights reserved.
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Effect of the lateral growth rate on wood properties in fast-growing hardwood species 査読あり
Kojima M., Yamamoto H., Okumura K., Ojio Y., Yoshida M., Okuyama T., Ona T., Matsune K., Nakamura K., Ide Y., Marsoem S., Sahri M., Hadi Y.
Journal of Wood Science 55 ( 6 ) 417 - 424 2009年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Wood Science
We investigated the feasibility of using several fast-growing tropical or subtropical hardwood species for timber production by measuring key wood qualities in relationship to the high rates of lateral growth. The trees tested were sampled from even-aged plantations of Acacia mangium, A. auriculiformis, hybrid Acacia (A. mangium × A. auriculiformis), Eucalyptus grandis, E. globulus, and Paraserianthes falcataria (Solomon and Java origin) that had already reached commercial harvesting age. The released strain of the surface growth stress (RS), xylem density (XD), microfibril angle (MFA), and fiber length (FL) were measured at the outermost part of the xylem at breast height in each tree. Results were then compared to the lateral growth rate (radius/age) at breast height, which provides a relative indicator of the amount of tree growth per year. Our findings indicated that RS was constant, regardless of lateral growth rate in each species. Similar results were observed for XD, MFA, and FL, with a few exceptions, suggesting that high growth rates do not intrinsically affect the wood properties of fast-growing tropical or subtropical species that have reached harvesting age. However, special attention must be paid to patterns of xylem maturation when developing plantations of such species. © The Japan Wood Research Society 2009.
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Excellent durability of carbon-supported Pt cathode catalysts covered with silica layers 査読あり
Matsumori H., Takenaka S., Matsune H., Kishida M.
ECS Transactions 25 ( 1 PART 1 ) 689 - 696 2009年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：ECS Transactions
Multi-walled carbon nanotube-supported platinum electrocatalysts (Pt/CNT) for cathode in polymer electrolyte fuel cells were covered with silica layers (SiO2/Pt/CNT) in order to improve the durability. SiO 2/Pt/CNT had a high catalytic activity in spite of uniform coverage of Pt metal with silica which was an insulator. The catalytic activity of SiO2/Pt/CNT did not change appreciably during the durability test (repeated potential cycling between 0.05 and 1.20V vs. RHE), whereas Pt/CNT was seriously deactivated. Silica layer which enveloped Pt metal particles in SiO2/Pt/CNT prevented the agglomeration of Pt metal particles as well as the growth of Pt metal particles in size through dissolution and redeposition of Pt metal. ©The Electrochemical Society.
DOI： 10.1149/1.3210620
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Dynamic Motion of Single Cells and its Relation to Cellular Properties 査読あり
Matsune H., Sakurai D., Hirukawa A., Takenaka S., Kishida M.
Molecular Nano Dynamics: Vol. I: Spectroscopic Methods and Nanostructures / Vol. II: Active Surfaces, Single Crystals and Single Biocells 2 689 - 702 2009年11月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Molecular Nano Dynamics: Vol. I: Spectroscopic Methods and Nanostructures / Vol. II: Active Surfaces, Single Crystals and Single Biocells
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Synthesis of hollow nanospheres consisting of amphiphilic block copolymers 査読あり
Matsune H., Sakurai D., Takenaka S., Kishida M.
Chemistry Letters 38 ( 7 ) 746 - 747 2009年7月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
Hollow polymeric nanospheres with shells consisting of inner hydrophilic and outer hydrophobic polymer chains are prepared by a surface-initiated living radical polymerization of 2-trimethylsilyloxyethyl acrylate and methyl methacrylate from initiator-modified silica nanoparticles; these nanospheres are subsequently prepared by intraparticle cross-linking and by dissolution of silica matrices with HF. The translation behavior of hydrophilic substrates from an aqueous phase to an oil phase through the nanocapsules is investigated. Copyright © 2009 The Chemical Society of Japan.
DOI： 10.1246/cl.2009.746
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Takenaka S., Matsumori H., Arike T., Matsune H., Kishida M.
Topics in Catalysis 52 ( 6-7 ) 731 - 738 2009年6月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Topics in Catalysis
Carbon nanotube (CNT)-supported Pt metal nanoparticles were covered with silica layers by hydrolysis of 3-aminopropyl-triethoxysilane (APTES) and/or tetraethoxysilane (TEOS). The hydrolysis of only APTES resulted in a uniform coverage of silica layers on Pt/CNT, but the thickness of the silica layers was very thin (<1 nm). Pt/CNT could also be coated with silica layers of a few nanometers in thickness by hydrolysis of TEOS, but exposed surfaces of CNTs in the sample were frequently observed. In contrast, the successive hydrolysis of APTES and TEOS brought about a uniform coverage of silica layers of a few nanometers in thickness on Pt/CNT. The silica-coated Pt/CNT showed high catalytic activity for electrochemical reactions in aqueous H2SO 4 electrolyte, in spite of a uniform coverage of Pt metal with silica layers. In addition, the coverage of Pt/CNT with silica layers improved its durability in electrochemical reactions. © Springer Science+Business Media, LLC 2009.
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Production of carbon nanotube by ethylene decomposition over silica-coated metal catalysts 査読あり
Iguchi T., Takenaka S., Nakagawa K., Orita Y., Matsune H., Kishida M.
Topics in Catalysis 52 ( 6-7 ) 563 - 570 2009年6月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Topics in Catalysis
Formation of carbon nanofibers (CNFs) and carbon nanotubes (CNTs) through the decomposition of ethylene at 973 K was achieved using various metal catalysts covered with silica layers. CNFs of various diameters were formed by ethylene decomposition over a Co metal catalyst supported on the outer surface of the silica. In contrast, silica-coated Co catalysts formed CNTs with uniform diameters by ethylene decomposition. Silicacoated Ni/SiO2 and Pt/carbon black also formed CNTs with uniform diameters, while CNFs and CNTs with various diameters were formed over Ni/SiO2 and Pt/carbon black without a silica coating. These results indicate that silica layers that envelop metal particles prevent sintering of the metal particles during ethylene decomposition. This results in the preferential formation of CNTs with a uniform diameter. © Springer Science+Business Media, LLC 2009.
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Takenaka S., Iguchi T., Tanabe E., Matsune H., Kishida M.
Carbon 47 ( 5 ) 1251 - 1257 2009年4月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Carbon
Ethylene decomposition was performed over supported Pt catalysts to fabricate composites of Pt metal nanoparticles and carbon nanotubes (CNTs). All supported Pt catalysts (Pt/carbon black, Pt/CNT, Pt/MgO, Pt/Al2O3 and Pt/SiO2) showed catalytic activity for ethylene decomposition at 973 K to form CNTs. Pt metal particles were found at tips of CNTs. These results indicate that Pt metal particles have catalytic activity for growth of CNTs through hydrocarbon decomposition. A broad range (5-50 nm) of CNT diameters were formed from the use of supported Pt metal catalysts although Pt metal particles in the catalysts before ethylene decomposition were relatively uniform in size (2-5 nm). These results imply that Pt metal particles in the catalysts aggregated during ethylene decomposition at 973 K. Aggregation of Pt metal particles in catalysts during ethylene decomposition could be suppressed by covering catalysts with silica layers that were a few nanometers thick. Silica-coated Pt catalysts showed high activity for ethylene decomposition to form CNTs with uniform diameters (8-10 nm) despite the uniform coverage of Pt metal particles with silica layers. © 2009 Elsevier Ltd. All rights reserved.
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High resistance to carbon deposition of silica-coated Ni catalysts in propane stream reforming 査読あり
Takenaka S., Orita Y., Umebayashi H., Matsune H., Kishida M.
Applied Catalysis A: General 351 ( 2 ) 189 - 194 2008年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Applied Catalysis A: General
The catalytic performance of Ni metal catalysts uniformly covered with layers of silica for propane steam reforming was compared with the performances of Ni metal catalysts supported on substrates of magnesia (MgO), alumina (Al2O3) and silica (SiO2). The silica-coated Ni catalysts showed high activity for propane steam reforming at 873 K. This catalytic activity is higher than the activity of effective light alkane steam reforming Ni/Al2O3 and Ni/MgO catalysts and we found that the catalytic activity of the silica-supported Ni metal was poor. The coverage of Ni metal particles with silica thus improves their catalytic activity for this reaction. Carbon deposition on silica-coated Ni catalysts during the steam reforming of propane at 873 K was lower than that on Ni/MgO and Ni/Al2O3. Ni K-edge XANES and EXAFS spectra of silica-coated Ni catalyst showed a strong interaction between Ni metal and silica. This interaction prevents the sintering of Ni metal particles during the propane steam reforming, which results in the reduction of carbon deposition on silica-coated Ni catalysts. These properties of silica-coated Ni catalysts result in high catalytic activity and improved catalyst stability. © 2008 Elsevier B.V. All rights reserved.
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Takenaka S., Iguchi T., Tanabe E., Matsune H., Kishida M.
Chemistry Letters 37 ( 9 ) 944 - 945 2008年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
Pt metal particles supported on carriers such as MgO and SiO2 showed high activity for the formation of carbon nanotubes (CNTs) through ethylene decomposition at 973 K. However, these CNTs were not uniform in diameter because of the sintering of Pt metal particles during the reaction. Covering Pt catalysts with silica prevented the sintering of Pt metal particles during ethylene decomposition, resulting in the formation of CNTs with a uniform diameter. Copyright © 2008 The Chemical Society of Japan.
DOI： 10.1246/cl.2008.944
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Takenaka S., Matsumori H., Matsune H., Tanabe E., Kishida M.
Journal of the Electrochemical Society 155 ( 9 ) 2008年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of the Electrochemical Society
Multiwalled carbon nanotube (CNT)-supported Pt nanoparticles (Pt/CNT) were covered with silica layers by successive hydrolysis of 3-aminopropyl- triethoxysilane and tetraethoxysilane on CNTs with Pt metal precursors, followed by reduction with hydrogen. The Pt/CNT covered with silica layers (SiO 2/Pt/CNT) was used as a cathode catalyst for a proton exchange membrane fuel cell (PEMFC). The activity of SiO2/Pt/CNT catalyst for the oxygen reduction reaction in a single-cell PEMFC was similar to that of Pt/CNT, in spite of the uniform coverage of Pt with silica layers, indicating that the coverage of Pt/CNT with silica layers did not appreciably decrease the catalytic activity. In addition, SiO2/Pt/CNT electrocatalyst showed high stability during potential cycling from 0.05 to 1.20 V vs reversible hydrogen electrode in an aqueous H2SO4 electrolyte, whereas Pt/CNT significantly deactivated during the experiment. The structural change of Pt species in these electrocatalysts during potential cycling was investigated by transmission electron microscopy images and Pt L III-edge X-ray absorption fine structure. The crystallite size of Pt metal in SiO2/Pt/CNT did not change appreciably during the potential cycling, while Pt metal crystallites in Pt/CNT seriously aggregated. Silica layers enveloping Pt metal particles in SiO2/Pt/CNT prevent the dissolution and redeposition of Pt metal particles as well as the agglomeration of Pt metal particles on the supports. © 2008 The Electrochemical Society.
DOI： 10.1149/1.2952665
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Preparation of carbon nanotube-supported metal nanoparticles coated with silica layers 査読あり
Takenaka S., Arike T., Matsune H., Tanabe E., Kishida M.
Journal of Catalysis 257 ( 2 ) 345 - 355 2008年7月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Catalysis
Carbon nanotube (CNT)-supported Pt metal (Pt/CNT) was covered with silica layers using hydrolysis of 3-aminopropyl-triethoxysilane (APTES) and/or tetraethoxysilane (TEOS). The hydrolysis of APTES resulted in a uniform coverage of Pt/CNT with silica layers, but the silica layers were very thin. Pt/CNT could be coated with silica layers of a few nanometers thickness by hydrolysis of TEOS, but the thickness was not uniform. In contrast, the successive hydrolysis of APTES and TEOS resulted in a uniform coverage of Pt/CNT with silica layers of a few nanometers thickness. Pt metal particles in silica-coated Pt/CNT adsorbed CO chemically despite uniform coverage of Pt metal particles with silica layers. Therefore, silica-coated Pt/CNT demonstrated high catalytic activity in methane combustion. © 2008 Elsevier Inc. All rights reserved.
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Asahi T., Matsune H., Yamashita K., Masuhara H., Kasai H., Nakanishi H.
Polish Journal of Chemistry 82 ( 4 ) 687 - 699 2008年4月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Polish Journal of Chemistry
Single particle fluorescence spectroscopy coupled with AFM observation is reported for perylene nanocrystals. Fluorescence spectral measurement for individual nanocrystals with the size from 100 nm to 500 nm and fluorescence anisotropy analysis demonstrate that the size dependence in fluorescence is in the intrinsic nature of nanometer-sized crystal of perylene. Single nanoparticle fluorescence shows the enhanced monomer (M-) emission compared to the bulk crystal and a blue-shift of excimer (E-) emission peak wavelength by decreasing the nanoparticle size. It is found for the first time that the size dependence is correlated well to the surface-to-volume ratio of nanocrystal. The size-dependent fluorescence is not attributed to a quantum confinement effect of exciton, but to a change in the elastic properties of nanocrystal with size, which in turn affects excimer formation. We discuss the decrease in elastic constant of crystalline lattice due to large surface-to-volume ratio, and propose an empirical formula on the size-dependence of E-emission peak in the framework of the strong coupling model of exciton-phonon interaction.
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Matsune H., Sakurai D., Niidome Y., Takenaka S., Kishida M.
Journal of Bioscience and Bioengineering 105 ( 1 ) 58 - 60 2008年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Bioscience and Bioengineering
The degree of dynamic morphological change of murine embryonic stem cells is investigated through direct observation by microscopy. As a result, we find that the degree of dynamic morphological change is proportional to the increase in the ratio of the cellular population in subculture. © 2008 The Society for Biotechnology, Japan.
DOI： 10.1263/jbb.105.58
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Improvement in the durability of Pt electrocatalysts by coverage with silica layers 査読あり
Takenaka S., Matsumori H., Nakagawa K., Matsune H., Tanabe E., Kishida M.
Journal of Physical Chemistry C 111 ( 42 ) 15133 - 15136 2007年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Physical Chemistry C
Carbon nanotube (CNT)-supported Pt metal nanoparticles were covered with silica layers by utilizing the successive hydrolysis of 3-aminopropyl- triethoxysilane and tetraethoxysilane on CNTs with Pt hydroxide. The CNT-supported Pt metal particles covered with silica layers (denoted as SiO 2/Pt/CNT) were used as the electrocatalysts. SiO2/Pt/CNT electrocatalysts showed a high stability for the repeated potential cycling experiment, whereas Pt/CNT electrocatalysts were deactivated seriously for the experiment because of the growth of Pt metal particles in size. The silica layers in SiO2/Pt/CNT prevent the dissolution of Pt metal particles as well as the migration and agglomeration of Pt metal particles on the supports, which results in the improvement of the stability of Pt/CNT electrocatalysts. © 2007 American Chemical Society.
DOI： 10.1021/jp076120b
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Takenaka S., Orita Y., Arike T., Matsune H., Tanabe E., Kishida M.
Chemistry Letters 36 ( 10 ) 1250 - 1251 2007年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
Silica-coated Pt-based alloys (Pt-Co and Pt-Pd alloys) were prepared using a water-in-oil-type microemulsion. The silica-coated Pt-based alloys decomposed ethylene to form composites composed of the catalysts and carbon nanotubes. Copyright © 2007 The Chemical Society of Japan.
DOI： 10.1246/cl.2007.1250
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Takenaka S., Orita Y., Matsune H., Tanabe E., Kishida M.
Journal of Physical Chemistry C 111 ( 21 ) 7748 - 7756 2007年5月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Physical Chemistry C
Silica-supported Co catalysts were prepared by using microemulsion. The structure and state of the Co species in the catalysts were characterized by TEM, XRD, Co K-edge XANES/EXAFS, and diffuse reflectance UV-vis spectroscopy. Co species in the catalysts prepared using microemulsion were atomically dispersed as Co2+ with tetrahedral symmetry (CoO4), even after reduction of the catalysts with hydrogen at 773 K, while Co metal particles were supported on the silica surface for the catalysts prepared by a conventional impregnation method. The Co catalysts prepared using microemulsion selectively formed multi-walled carbon nanotubes with a uniform diameter by the decomposition of ethylene at 973 K, whereas silica-supported Co catalysts prepared by the impregnation method formed carbon nanofibers with various diameters. In addition, the Co catalysts prepared using microemulsion formed bundles of single- or double-walled carbon nanotubes by methane decomposition at 1073 K. Contact of the Co catalysts with hydrocarbons at the reaction temperatures (973 or 1073 K) resulted in the reduction of atomically dispersed Co oxide species to form small Co metal particles, which grew carbon nanotubes through hydrocarbon decomposition. © 2007 American Chemical Society.
DOI： 10.1021/jp070826o
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Production of CO-free hydrogen through the decomposition of LPG and kerosene over Ni-based catalysts 査読あり
Takenaka S., Kawashima K., Matsune H., Kishida M.
Applied Catalysis A: General 321 ( 2 ) 165 - 174 2007年4月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Applied Catalysis A: General
The catalytic performance of Ni-based catalysts for the decomposition of hydrocarbons of C3-C8 into CO-free hydrogen and carbon fibers was investigated in order to produce CO-free hydrogen as a fuel for PEFC from liquefied petroleum gas (LPG) and kerosene. The addition of Cu or Pd into Ni/SiO2 catalyst elongated its catalytic life for the propane decomposition. Especially, Ni-Pd/SiO2 catalyst showed higher activity and longer life for the decomposition of propane at 823 and 873 K, compared to Ni/SiO2 and Ni-Cu/SiO2 catalysts. Ni-Pd/SiO2 catalyst was deactivated gradually with time on stream during the decomposition of propane due to the deposition of large amounts of carbon. However, the activity of the catalyst for the propane decomposition was recovered completely by the gasification of deposited carbon with CO2 into CO. This result suggested that CO-free hydrogen and CO could be produced successively through the decomposition of hydrocarbons and the subsequent gasification of deposited carbon with CO2. Ni-Pd/SiO2 showed high catalytic activity for the decomposition of hydrocarbons of C6-C8 to form CO-free hydrogen. Thus, CO-free hydrogen was produced through the decomposition of commercial kerosene over Ni-Pd/SiO2 catalyst. © 2007 Elsevier B.V. All rights reserved.
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Nakagawa K., Takenaka S., Imagawa S., Matsune H., Kishida M.
Chemistry Letters 36 ( 2 ) 252 - 253 2007年2月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
Carbon nanofibers with uniform diameter of 10-15 nm were produced by the decomposition of ethylene over silica-supported Ni catalysts covered with silica layers. Copyright © 2007 The Chemical Society of Japan.
DOI： 10.1246/cl.2007.252
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Takenaka S., Umebayashi H., Tanabe E., Matsune H., Kishida M.
Journal of Catalysis 245 ( 2 ) 392 - 400 2007年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Catalysis
Silica-supported Ni catalysts were prepared by using water-in-oil typed microemulsion. By preparation using the microemulsion, Ni metal particles with diameters < ca. 5 nm were covered uniformly with silica layers with thickness of ca. 10 nm, whereas Ni metal particles were supported on the outer surface of silica by a conventional impregnation method. The Ni metal covered with silica (coat-Ni) showed excellent catalytic performance for the partial oxidation of methane into synthesis gas. Coat-Ni showed a high activity and a long life for the partial oxidation of methane at temperatures above 973 K to form CO and hydrogen, whereas Ni metal catalyst supported on silica was rapidly deactivated for the reaction. Ni K-edge XANES/EXAFS and temperature-programmed reduction for these catalysts showed that Ni metal particles in coat-Ni strongly interacted with silica. The strong interaction of Ni metal particles with silica would improve their catalytic performance for the partial oxidation of methane into synthesis gas. © 2006 Elsevier Inc. All rights reserved.
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One-pot synthesis and characterization of laccase-entrapped magnetic nanobeads 査読あり
Matsune H., Jogasaki H., Date M., Takenaka S., Kishida M.
Chemistry Letters 35 ( 12 ) 1356 - 1357 2006年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
We report the simple one-pot synthesis of magnetic nanoparticles coated with silica-gel layers that entrap laccase (Lc) by the water-in-oil microemulsion method. The amorphous porous structure of the silica layer enables the entrapped Lc to react with substrates in solution. The enzymatic activity is studied using Michaelis-Menten kinetics. The reusability of the magnetic nanoparticles is examined. Copyright © 2006 The Chemical Society of Japan.
DOI： 10.1246/cl.2006.1356
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Matsune H., Tago T., Shibata K., Wakabayashi K., Kishida M.
Journal of Nanoparticle Research 8 ( 6 ) 1083 - 1087 2006年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Nanoparticle Research
A nonionic reverse-micelle based approach is described for fabrication of a network structure consisting of chain-like arrays of gold nanoparticles followed by coating process with a uniform silica layer using a sol-gel method. The hexadecyl-poly (ethylene oxide-15) ether (designated C16E 15) is used as a template for this study. The effects of a water-to-surfactant molar ratio (w) as well as the concentration of tetraethyl orthosilicate ([TEOS]oil) are investigated on the resulting organized structures. © Springer Science+Business Media Inc. 2006.
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Asahi T., Volkov V., Matsune H., Kawai H., Masuhara H.
Proceedings - Electrochemical Society PV 2004-22 150 - 161 2006年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Proceedings - Electrochemical Society
We have developed a dark-field optical microspectrscopic system coupled with AFM measurement, and applied it to 1, 6-di(N-carbazolyl)-2-4-hexadiyne (DCHD) nanocrystal systems. We revealed clearly the size and shape dependent peak of the polymer-backbone electronic transition of individual poly-DCHD nanocrystals. It was found that the peak energy of the resonant Rayleigh scattering spectra shifted to a lower energy for nanocrystals having larger cross-section against its long axis. In situ observation of photopolymerization of individual monomer DCHD nanocrystals is also descried. It has been successfully demonstrated that the morphological of fibrous nanocrystal changes upon polymerization. Our single particle results demonstrate that far-field microscopy coupled with AFM is a reliable experimental approach for investigating optical properties and photochemistry of organic nanoparticles.
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Hori K., Matsune H., Takenaka S., Kishida M.
Science and Technology of Advanced Materials 7 ( 7 ) 678 - 684 2006年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Science and Technology of Advanced Materials
Pt-SiO2 catalysts were prepared by using water-in-oil type microemulsion. The catalysts were prepared by hydrolysis of tetraethylorthosilicate in the microemulsion containing Pt species, followed by calcination in air and reduction with H2. This preparation method for Pt-SiO2 provided Pt metal nanoparticles with a diameter of ca. 6 nm covered uniformly with silica layers, while a conventional impregnation method formed Pt metal particles supported on the silica surface. The Pt catalysts coated with silica (coat-Pt) showed different catalytic performance for the competitive oxidation of mixed hydrocarbons from Pt catalysts supported on silica (imp-Pt), i.e. in the competitive oxidation of methane and iso-butane, coat-Pt catalysts preferentially oxidized methane, while iso-butane was oxidized selectively over imp-Pt catalysts. The results of the adsorption of Ar on coat-Pt showed that silica in coat-Pt had porous structures of pore diameters <1 nm. Because the porous structure of silica, which wrapped Pt metal particles, controlled the diffusion rate of reactant molecules, coat-Pt showed a specific catalytic performance for competitive oxidation. © 2006.
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Imagawa S., Inoke K., Kaneko K., Matsune H., Nakagawa K., Takenaka S., Kishida M.
Chemistry Letters 35 ( 7 ) 816 - 817 2006年7月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
Novel submicron scale composites with hollow hexagonal cylinder structures were prepared by hydrolysis of tetraethyl orthosilicate in a micelle solution composed of polyoxyethylene (n = 15) cetyl ether/cyclohexane/water containing Co-N 2H 4 compound nanoparticles. Copyright © 2006 The Chemical Society of Japan.
DOI： 10.1246/cl.2006.816
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Takenaka S., Hori K., Matsune H., Kishida M.
Studies in Surface Science and Catalysis 162 585 - 592 2006年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Studies in Surface Science and Catalysis
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Takenaka S., Hori K., Matsune H., Kishida M.
Chemistry Letters 34 ( 12 ) 1594 - 1595 2005年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry Letters
Pt metal catalyst covered with silica layers oxidized methane preferentially in the competitive oxidation of methane and isobutane with gaseous oxygen. Selectivity in the competitive oxidation of mixed hydrocarbons over the catalyst was controlled by the diffusion rates of the reactants in the silica layers which wrapped Pt metal particles. Copyright © 2005 The Chemical Society of Japan.
DOI： 10.1246/cl.2005.1594
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Wei Z., Ujiiye-Ishii K., Masuhara A., Kasai H., Okada S., Matsune H., Asahi T., Masuhara H., Nakanishi H.
Journal of Nanoscience and Nanotechnology 5 ( 6 ) 937 - 944 2005年11月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Nanoscience and Nanotechnology
Monodispersed polymer/polydiacetylene composite particles were synthesized by soap-free seeded emulsion polymerization of styrene and methyl methacrylate; the products were characterized by XRD, SEM, TEM, UV-visible spectroscopy, and single particle scattering spectroscopy. In the synthesis process, polydiacetylene nanocrystals were found to act as inhibitor, and consequently a relatively low concentration was necessary. Different monomers lead to the differences in reaction condition and particle morphology; the PMMA composite particles were simpler in preparation than polystyrene particles, but the latter have better spherical morphology. The composite particles were composed of polymer shells and polydiacetylene cores, which kept their crystal structure and optical properties. A high percentage of cored particles could be achieved with optimized reaction conditions where the amount of seed was sufficient and the oily oligomer by-product was suppressed. Copyright © 2005 American Scientific Publishers All rights reserved.
DOI： 10.1166/jnn.2005.121
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Matsune H., Asahi T., Masuhara H., Kasai H., Nakanishi H.
Materials Research Society Symposium Proceedings 846 263 - 268 2005年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Materials Research Society Symposium Proceedings
This paper presents single particle fluorescence spectroscopy of perylene nanocrystals coupled with AFM observation of their topographic shapes. The fluorescence spectra of individual nanocrystals confirmed clearly and precisely a blue-shift in the excimer emission maximum on the reduction of their volume. The result can be explained in terms of "lattice softening", which makes intermolecular interaction weaker and modified the energy level of the excimer state in nanocrystal. © 2005 Materials Research Society.
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Yonezawa T., Matsune H., Kimizuka N.
Advanced Materials 15 ( 6 ) 499 - 503 2003年3月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Advanced Materials
A general strategy for preparing a stable assembly of nanoparticles was demonstrated. It was emphasized that almost all the titanium dioxide-wrapped particles could be dispersed independently using this technique and their aggregation was not observed. As such, this nanoparticle assembly and wrapping technology can be widely applied to other metal and semiconductor particles as well as to nanosized materials.
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Layered nanocomposite of close-packed gold nanoparticles and TiO<inf>2</inf> gel layers 査読あり
Yonezawa T., Matsune H., Kunitake T.
Chemistry of Materials 11 ( 1 ) 33 - 35 1999年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Chemistry of Materials
A study is conducted to demonstrate how layered nanocomposite of close-packed gold nanoparticles and TiO2 gel layers. The study demonstrates the preparation of alternate layers of ultrathin TiO2 films and modified gold nanoparticles. The modified gold nanoparticle possesses surface hydroxyl groups, and they behave as an active component in the surface sol-gel process. Nanocomposites obtained from these components will be composed of high concentrations of nanoparticles in metal oxide thin films. Gold nanoparticles are prepared by reduction of HAuCl4 by NaBH4 in methanol/acetic acid in the presence of (SC11OH)2. Each particle had a spherical shape of a uniform size.
DOI： 10.1021/cm980687a