2021/10/26 更新

写真a

コダマ タツヤ
兒玉 竜也
KODAMA Tatsuya
所属
教育研究院 自然科学系 生産デザイン工学系列 教授
自然科学研究科 材料生産システム専攻 教授
工学部 工学科 教授
職名
教授
外部リンク

学位

  • 博士(理学) ( 1994年3月   東京工業大学 )

研究キーワード

  • Inorganic Material

  • 太陽熱化学

  • Catalyst

  • 触媒

  • 無機材料

  • 水素エネルギー

  • 資源利用化学

  • Energy Science

研究分野

  • ナノテク・材料 / エネルギー化学

  • ナノテク・材料 / 機能物性化学

  • ナノテク・材料 / 無機物質、無機材料化学

経歴(researchmap)

  • 新潟大学

    1997年 - 2003年

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  • 新潟大学工学部 助手   Faculty of Engineering

    1995年 - 1997年

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  • Niigata University, Faculty of Engineering, Research Associate

    1995年 - 1996年

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  • Post doctoral Fellows, Japan Society for the Promotion of Science

    1994年 - 1995年

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  • 日本学術振興会 特別研究員

    1994年 - 1995年

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経歴

  • 新潟大学   工学部 工学科   教授

    2017年4月 - 現在

  • 新潟大学   自然科学研究科 材料生産システム専攻   教授

    2004年4月 - 現在

  • 新潟大学   自然科学研究科 材料生産システム専攻   教授

    2004年4月 - 現在

  • 新潟大学   化学システム工学科   教授

    2003年4月 - 2017年3月

  • 新潟大学   工学部   助教授

    1997年4月 - 2003年3月

  • 新潟大学   工学部   助手

    1995年4月 - 1997年3月

▶ 全件表示

所属学協会

委員歴

  • 日本エネルギー学会   新エネルギー部門幹事  

    2003年   

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    団体区分:学協会

    日本エネルギー学会

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  • 生態工学会   理事  

    2001年   

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    団体区分:学協会

    生態工学会

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書籍等出版物

  • Efficient thermochemical cycle for CO<sub>2</sub> reduciton with coal using a reactive redox system of ferrite

    Studies in Suface Science and Catalysis  1998年 

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MISC

  • Stepwise production of CO-rich syngas and hydrogen via methane reforming by a WO3-redox catalyst

    T Kodama, T Shimizu, T Satoh, KI Shimizu

    ENERGY   28 ( 11 )   1055 - 1068   2003年9月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A two-step cyclic steam reforming of methane by a WO3/ZrO2 redox catalyst was performed to produce CO-rich syngas and hydrogen. The two-step cyclic processes could be repeated using a redox system of WO3 below 1273 K. The produced CO-rich syngas had the H-2/CO ratios of about two, which was suitable for methanol production. This endothermic syngas-production process will be used as a solar thermochemical process for converting concentrated solar radiation to chemical liquid fuel of methanol in the sun-belt regions. The solar syngas-production process using the WO3/ZrO2 catalyst was demonstrated in a laboratory scale under direct irradiation of the catalyst by a solar-simulated, high-flux visible light. (C) 2003 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0360-5442(03)00093-8

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  • Stepwise production of CO-rich syngas and hydrogen via methane reforming by a WO3-redox catalyst

    T Kodama, T Shimizu, T Satoh, KI Shimizu

    ENERGY   28 ( 11 )   1055 - 1068   2003年9月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A two-step cyclic steam reforming of methane by a WO3/ZrO2 redox catalyst was performed to produce CO-rich syngas and hydrogen. The two-step cyclic processes could be repeated using a redox system of WO3 below 1273 K. The produced CO-rich syngas had the H-2/CO ratios of about two, which was suitable for methanol production. This endothermic syngas-production process will be used as a solar thermochemical process for converting concentrated solar radiation to chemical liquid fuel of methanol in the sun-belt regions. The solar syngas-production process using the WO3/ZrO2 catalyst was demonstrated in a laboratory scale under direct irradiation of the catalyst by a solar-simulated, high-flux visible light. (C) 2003 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0360-5442(03)00093-8

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  • Fe3+-exchanged fluorotetrasilicic mica as an active and reusable catalyst for Michael reaction

    K Shimizu, M Miyagi, T Kan-no, T Kodama, Y Kitayama

    TETRAHEDRON LETTERS   44 ( 40 )   7421 - 7424   2003年9月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Fe3+-exchanged fluorotetrasilicic mica acts as a highly effective and reusable catalyst for the solventless Michael reaction of beta-ketoesters with vinyl ketones under mild condition. The immobilized catalyst shows higher activity than homogeneous Fe3+ catalysts, FeCl(3)(.)6H(2)O and Fe(NO3)(3)(.)9H(2)O. (C) 2003 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2003.08.048

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  • Ni-Mg-O catalyst driven by direct light irradiation for catalytically-activated foam absorber in a solar reforming receiver-reactor

    T Kodama, A Kiyama, T Moriyama, T Yokoyama, KI Shimizu, H Andou, N Satou

    ENERGY & FUELS   17 ( 4 )   914 - 921   2003年7月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    A nickel-magnesia solid solution Ni-Mg-O was examined as a catalyst for solar CO2 reforming of methane. The activity was tested in a laboratory-scale transparent (quartz) reactor under direct irradiation of the catalyst by high-flux visible light from a sun-simulator. The 8-11 wt % Ni-Mg-O catalyst gave the high reforming activity or about 100% of chemical conversion, with little coking, under a high-flux irradiation of 890 kW m(-2) and at a short residence time of about 0.15 s while passing a 1:1 CH4-CO2 gas mixture at 1 atm. The comparison of the activity data with those obtained in a light-irradiated, nontransparent (steel) reactor showed that the intensification of heat supply by the direct light irradiation of the Ni-Mg-O catalyst leads to considerable reaction rate enhancement. Applying this Ni-Mg-O catalyst, a new type of "catalytically activated" ceramic (alumina) foam absorber was prepared and tested on activity in a laboratory-scale volumetric receiver-reactor using the sun-simulator. This new absorber may be applied in solar receiver-reactor systems for converting concentrated solar high fluxes to chemical fuels via endothermic natural-gas reforming.

    DOI: 10.1021/ef020270y

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  • Ni-Mg-O catalyst driven by direct light irradiation for catalytically-activated foam absorber in a solar reforming receiver-reactor

    T Kodama, A Kiyama, T Moriyama, T Yokoyama, KI Shimizu, H Andou, N Satou

    ENERGY & FUELS   17 ( 4 )   914 - 921   2003年7月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    A nickel-magnesia solid solution Ni-Mg-O was examined as a catalyst for solar CO2 reforming of methane. The activity was tested in a laboratory-scale transparent (quartz) reactor under direct irradiation of the catalyst by high-flux visible light from a sun-simulator. The 8-11 wt % Ni-Mg-O catalyst gave the high reforming activity or about 100% of chemical conversion, with little coking, under a high-flux irradiation of 890 kW m(-2) and at a short residence time of about 0.15 s while passing a 1:1 CH4-CO2 gas mixture at 1 atm. The comparison of the activity data with those obtained in a light-irradiated, nontransparent (steel) reactor showed that the intensification of heat supply by the direct light irradiation of the Ni-Mg-O catalyst leads to considerable reaction rate enhancement. Applying this Ni-Mg-O catalyst, a new type of "catalytically activated" ceramic (alumina) foam absorber was prepared and tested on activity in a laboratory-scale volumetric receiver-reactor using the sun-simulator. This new absorber may be applied in solar receiver-reactor systems for converting concentrated solar high fluxes to chemical fuels via endothermic natural-gas reforming.

    DOI: 10.1021/ef020270y

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  • Catalytically activated metal foam absorber for light-to-chemical energy conversion via solar reforming of methane

    T Kodama, A Kiyama, KI Shimizu

    ENERGY & FUELS   17 ( 1 )   13 - 17   2003年1月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    CO2 reforming of methane was examined under direct irradiation of the catalytically activated metal foam absorber by solar-simulated, concentrated visible light in the small receiver- reactor system with a transparent window. Rh, Ru, or Ni was applied as the active metal on the aluminacoated or noncoated Ni-Cr-Al metal foam disk for the preparation of the absorber. Rh showed the best activity on the noncoated metal foam while Ru was the best on the alumina-coated one. The most active and stable RU Al2O3/Ni-Cr-Al-foam absorber yielded a maximum methane conversion of 73% at a GHSV of 8500 h(-1) and at ambient pressure, in which about 50% of the incident light energy reaching the absorber was stored as chemical enthalpy at a relatively low value of the average input-power density of radiation, rho = 180 kW m(-2) (the peak flux density of 274 kW m-2 at the center of the irradiated surface of the absorber). This catalytically activate metal foam absorber will be used in the receiver-reactor system for solar methane reforming at relatively low-energy fluxes of concentrated solar radiation.

    DOI: 10.1021/ef0200525

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  • Catalytically activated metal foam absorber for light-to-chemical energy conversion via solar reforming of methane

    T Kodama, A Kiyama, KI Shimizu

    ENERGY & FUELS   17 ( 1 )   13 - 17   2003年1月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    CO2 reforming of methane was examined under direct irradiation of the catalytically activated metal foam absorber by solar-simulated, concentrated visible light in the small receiver- reactor system with a transparent window. Rh, Ru, or Ni was applied as the active metal on the aluminacoated or noncoated Ni-Cr-Al metal foam disk for the preparation of the absorber. Rh showed the best activity on the noncoated metal foam while Ru was the best on the alumina-coated one. The most active and stable RU Al2O3/Ni-Cr-Al-foam absorber yielded a maximum methane conversion of 73% at a GHSV of 8500 h(-1) and at ambient pressure, in which about 50% of the incident light energy reaching the absorber was stored as chemical enthalpy at a relatively low value of the average input-power density of radiation, rho = 180 kW m(-2) (the peak flux density of 274 kW m-2 at the center of the irradiated surface of the absorber). This catalytically activate metal foam absorber will be used in the receiver-reactor system for solar methane reforming at relatively low-energy fluxes of concentrated solar radiation.

    DOI: 10.1021/ef0200525

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  • Novel Na-3-mica: Alkaline earth cation exchange and immobilization

    T Kodama, K Hasegawa, K Shimizu, S Komarneni

    SEPARATION SCIENCE AND TECHNOLOGY   38 ( 3 )   679 - 694   2003年

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    記述言語:英語   出版者・発行元:MARCEL DEKKER INC  

    The cation-exchange capacities for the alkaline earth metals Ba, Mg, and Ca, and their immobilization in the interlayers of a novel swelling fluorine mica (Na-3-mica) with a high-layer-charge density were studied. The mica was fully exchanged or saturated with Ba, Mg, and Ca ions and the cation-exchange capacities were determined to be 246, 338, and 322 meq(100 g)(-1), respectively, on anhydrous basis of mica. The chemical analyses of the saturated micas indicated that about three exchangeable interlayer sodium ions per unit cell existed in the mica as a result of the total negative layer charge due to both Mg vacancies in octahedral sheets and Al substitution in tetrahedral Si sheets of the silicate. The Ba, Mg, and Ca leachabilities of the saturated micas were investigated in 0.5 M NaCl background solutions at room temperature and these were compared to the Sr leachability of the Sr-saturated mica. The degree of the cation immobilization in the interlayers increased in the order of Ca &lt; Sr &lt; Ba &lt; Mg. This could be explained by the interlayer spacings and structures of the saturated micas.

    DOI: 10.1081/SS-120016659

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  • Novel Na-3-mica: Alkaline earth cation exchange and immobilization

    T Kodama, K Hasegawa, K Shimizu, S Komarneni

    SEPARATION SCIENCE AND TECHNOLOGY   38 ( 3 )   679 - 694   2003年

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    記述言語:英語   出版者・発行元:MARCEL DEKKER INC  

    The cation-exchange capacities for the alkaline earth metals Ba, Mg, and Ca, and their immobilization in the interlayers of a novel swelling fluorine mica (Na-3-mica) with a high-layer-charge density were studied. The mica was fully exchanged or saturated with Ba, Mg, and Ca ions and the cation-exchange capacities were determined to be 246, 338, and 322 meq(100 g)(-1), respectively, on anhydrous basis of mica. The chemical analyses of the saturated micas indicated that about three exchangeable interlayer sodium ions per unit cell existed in the mica as a result of the total negative layer charge due to both Mg vacancies in octahedral sheets and Al substitution in tetrahedral Si sheets of the silicate. The Ba, Mg, and Ca leachabilities of the saturated micas were investigated in 0.5 M NaCl background solutions at room temperature and these were compared to the Sr leachability of the Sr-saturated mica. The degree of the cation immobilization in the interlayers increased in the order of Ca &lt; Sr &lt; Ba &lt; Mg. This could be explained by the interlayer spacings and structures of the saturated micas.

    DOI: 10.1081/SS-120016659

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  • High-temperature solar chemistry for converting solar heat to chemical fuels

    T Kodama

    PROGRESS IN ENERGY AND COMBUSTION SCIENCE   29 ( 6 )   567 - 597   2003年

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    記述言語:英語   掲載種別:書評論文,書評,文献紹介等   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    This paper reviews the recent developments on thermochemical conversion of concentrated solar high temperature beat to chemical fuels. The conversion has the advantage of producing long term storable energy carriers from solar energy. This conversion also enables solar energy transportation from the sunbelt to remote population centers. The thermochemical pathway is characterized by a theoretical high efficiency. However, there are solar peculiarities in comparison to conventional thermochemical processes-high thermal flux density and frequent thermal transients because of the fluctuating insolation-, and conventional industrial thermochemical processes are generally not suitable for solar driven processes. Therefore, the adaptation to such peculiarities of solar thermochemical processes has been the important R&D task in this research field. Thermochemical water splitting, steam or CO2 gasification of coal, steam or CO2 reforming of methane, and hydrogenetive coupling of methane, are industrially important, endothermic processes to produce useful chemical fuels such as hydrogen, synthesis gas and C-2-hydrocarbons, which have been examined as solar thermochemical processes. The technical. developments and feasibilities to conduct these endothermic processes by utilizing concentrated solar radiation as the process heat are discussed here. My recent experimental results to improve the advanced solar thermochemical technologies are also given. (C) 2003 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/S0360-1285(03)00059-5

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  • High-temperature solar chemistry for converting soalr heat to chemical fuels

    Progress in Energy and Combustion Science   Vol. 29, pp. 567-597   2003年

  • Photocatalytic water splitting over spontaneously hydrated layered tantalate A(2)SrTa(2)O(7)center dot nH(2)O (A=H,K,Rb)

    K Shimizu, Y Tsuji, M Kawakami, K Toda, T Kodama, M Sato, Y Kitayama

    CHEMISTRY LETTERS   No.11, pp.1158-1159 ( 11 )   1158 - 1159   2002年11月

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    記述言語:英語   出版者・発行元:CHEMICAL SOC JAPAN  

    A series of layered perovskite-type tantalates with hydrated interlayer space, A(2)SrTa(2)O(7).nH(2)O (A=H, K, Rb), exhibited efficient photocatalytic activity for water splitting into H-2/O-2 mixture under UV irradiation without loading metal co-catalysts.

    DOI: 10.1246/cl.2002.1158

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  • Photocatalytic degradation of hexachlorocyclohexane (HCH) by TiO2-pillared fluorine mica

    F Murayama, K Shimizu, N Tsukada, A Shimada, T Kodama, Y Kitayama

    CHEMICAL COMMUNICATIONS   pp.2678-2679 ( 22 )   2678 - 2679   2002年11月

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    A significant effect of clay host was observed on the photocatalytic activity of TiO2; TiO2-pillared fluorine mica exhibited two orders of magnitude higher activity than TiO2 and TiO2-pillared montmorillonite for the photocatalytic degradation of gamma-HCH.

    DOI: 10.1039/b206825g

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  • Photocatalytic degradation of hexachlorocyclohexane (HCH) by TiO2-pillared fluorine mica

    F Murayama, K Shimizu, N Tsukada, A Shimada, T Kodama, Y Kitayama

    CHEMICAL COMMUNICATIONS   pp.2678-2679 ( 22 )   2678 - 2679   2002年11月

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    A significant effect of clay host was observed on the photocatalytic activity of TiO2; TiO2-pillared fluorine mica exhibited two orders of magnitude higher activity than TiO2 and TiO2-pillared montmorillonite for the photocatalytic degradation of gamma-HCH.

    DOI: 10.1039/b206825g

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  • Photocatalytic water splitting over spontaneously hydrated layered tantalate A(2)SrTa(2)O(7)center dot nH(2)O (A=H,K,Rb)

    K Shimizu, Y Tsuji, M Kawakami, K Toda, T Kodama, M Sato, Y Kitayama

    CHEMISTRY LETTERS   No.11, pp.1158-1159 ( 11 )   1158 - 1159   2002年11月

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    記述言語:英語   出版者・発行元:CHEMICAL SOC JAPAN  

    A series of layered perovskite-type tantalates with hydrated interlayer space, A(2)SrTa(2)O(7).nH(2)O (A=H, K, Rb), exhibited efficient photocatalytic activity for water splitting into H-2/O-2 mixture under UV irradiation without loading metal co-catalysts.

    DOI: 10.1246/cl.2002.1158

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  • Role of Intracrystalline Tunnels of Sepiolite for Catalytic Activity

    Studies in Surface Science and Catalysis   Vol.142, pp.675-682   2002年10月

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  • Fluidized bed coal gasification with CO2 under direct irradiation with concentrated visible light

    T Kodama, Y Kondoh, T Tamagawa, A Funatoh, KI Shimizu, Y Kitayama

    ENERGY & FUELS   16 ( 5 )   1264 - 1270   2002年9月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Solar CO2 gasification of coal was demonstrated under direct irradiation of the fluidized coal bed with the concentrated visible light from a solar furnace simulator in a small-scale quartz reactor. Pulverized Australian bituminous coal (the average particle size of 140 pm) was tested. The peak energy-flux density, FDpeak of the incident light beam was varied up to 1270 kW m(-2). The light-to-chemical (enthalpy) energy conversion via the solar gasification increased with increasing the energy-flux density of irradiation. The maximum energy conversion of 8% was obtained at the optimum gas velocity for fluidization of 0.96 N in min(-1).

    DOI: 10.1021/ef020053x

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  • Nickel catalyst driven by direct light irradiation for solar CO2-reforming of methane

    T Kodama, H Ohtake, KI Shimizu, Y Kitayama

    ENERGY & FUELS   16 ( 5 )   1016 - 1023   2002年9月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Catalytic activity and selectivity of Ni catalysts for solar CO2-reforming of methane were examined under direct irradiation of the catalyst by solar-simulated, concentrated Xe-arc lamp light, using a small-scaled transparent (quartz) packed-bed reactor. The Ni catalysts (17 wt %-Ni), supported with alpha-Al2O3, SiO2, ZrO2, and TiO2, were tested, and the Ni/alpha-Al2O3 showed the best activity and selectivity under the solar simulation, as well as under direct irradiation by infrared light. With the Ni/alpha-Al2O3 catalyst at the energy flux density of the incident light = 810 kW m(-2) and at the GHSV = 18700 h(-1), more than 90% of methane was chemically converted to syngas, in which 16% of the incident light energy wag stored as chemical enthalpy. The activity data were compared to those for the catalyst irradiated by infrared light or UV-cut Xe light at various reaction temperatures or incident energy flux densities. This comparison indicated that the solar-simulated reforming with the Ni/alpha-Al2O3 was scarcely enhanced by UV-photochemical effect and that the activity was mainly determined by the thermochemical effect or the catalyst-bed temperature.

    DOI: 10.1021/ef000226n

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  • Nickel catalyst driven by direct light irradiation for solar CO2-reforming of methane

    T Kodama, H Ohtake, KI Shimizu, Y Kitayama

    ENERGY & FUELS   16 ( 5 )   1016 - 1023   2002年9月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Catalytic activity and selectivity of Ni catalysts for solar CO2-reforming of methane were examined under direct irradiation of the catalyst by solar-simulated, concentrated Xe-arc lamp light, using a small-scaled transparent (quartz) packed-bed reactor. The Ni catalysts (17 wt %-Ni), supported with alpha-Al2O3, SiO2, ZrO2, and TiO2, were tested, and the Ni/alpha-Al2O3 showed the best activity and selectivity under the solar simulation, as well as under direct irradiation by infrared light. With the Ni/alpha-Al2O3 catalyst at the energy flux density of the incident light = 810 kW m(-2) and at the GHSV = 18700 h(-1), more than 90% of methane was chemically converted to syngas, in which 16% of the incident light energy wag stored as chemical enthalpy. The activity data were compared to those for the catalyst irradiated by infrared light or UV-cut Xe light at various reaction temperatures or incident energy flux densities. This comparison indicated that the solar-simulated reforming with the Ni/alpha-Al2O3 was scarcely enhanced by UV-photochemical effect and that the activity was mainly determined by the thermochemical effect or the catalyst-bed temperature.

    DOI: 10.1021/ef000226n

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  • Fluidized bed coal gasification with CO2 under direct irradiation with concentrated visible light

    T Kodama, Y Kondoh, T Tamagawa, A Funatoh, KI Shimizu, Y Kitayama

    ENERGY & FUELS   16 ( 5 )   1264 - 1270   2002年9月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Solar CO2 gasification of coal was demonstrated under direct irradiation of the fluidized coal bed with the concentrated visible light from a solar furnace simulator in a small-scale quartz reactor. Pulverized Australian bituminous coal (the average particle size of 140 pm) was tested. The peak energy-flux density, FDpeak of the incident light beam was varied up to 1270 kW m(-2). The light-to-chemical (enthalpy) energy conversion via the solar gasification increased with increasing the energy-flux density of irradiation. The maximum energy conversion of 8% was obtained at the optimum gas velocity for fluidization of 0.96 N in min(-1).

    DOI: 10.1021/ef020053x

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  • Suzuki cross-coupling reaction catalyzed by palladium-supported sepiolite

    Ken-Ichi Shimizu, Toshiki Kan-No, Tatsuya Kodama, Hisahiro Hagiwara, Yoshie Kitayama

    Tetrahedron Letters   43 ( 32 )   5653 - 5655   2002年8月

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    記述言語:英語  

    Palladium-supported sepiolite clay has effectively catalyzed the Suzuki cross-coupling reaction of phenylboronic acid with aryl halide including less reactive electron-rich aryl bromides. © 2002 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(02)01132-2

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  • Synthesis of Novel Na-Rich Mica and Selective Strontium Ion Exchange and Fixation

    Separation Science and Technology   Vol.37, 1927-1942   2002年8月

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  • Selective oxidation of liquid hydrocarbons over photoirradiated TiO2 pillared clays

    Ken-Ichi Shimizu, Toshio Kaneko, Tomokazu Fujishima, Tatsuya Kodama, Hisao Yoshida, Yoshie Kitayama

    Applied Catalysis A: General   225 ( 1-2 )   185 - 191   2002年2月

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    記述言語:英語  

    Selective photo-oxidation of benzene and cyclohexane were investigated by using TiO2 pillared clays (mica, montmorillonite and saponite). The characterization results indicated that all the TiO2 pillared clays contain TiO2 with similar structure, anatase-like small particles, in the different silicate layers of clays. The solvent effect on the photo-oxidation of benzene on TiO2 pillared clay was significant
    both the activity and selectivity were increased by an addition of 10% water in acetonitrile solvent and they were further increased when the reaction was performed in an aqueous environment. In the latter condition, TiO2 pillared clays showed higher selectivity to oxygenates than TiO2 (Degussa P25). The product distribution among oxygenates also depends on the type of the clay host, indicating that the photocatalytic properties of TiO2 depend strongly on the type of clay host. For the cyclohexane photo-oxidation, TiO2 pillared clay showed much higher selectivity than TiO2, possibly because of the hydrophobic nature of pillared clay. © 2002 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0926-860X(01)00863-8

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  • Stepwise Productin of CO-Rich Syngas and Hydrogen via Solar Methane Reforming by Using a Ni(II)-Ferrite Redox System

    Solar Energy   Vol. 73, No. 5, pp. 363-374   2002年

  • Synthesis of Novel Na-Rich Mica and Selective Strontium Ion Exchange and Fixation

    Separation Science and Technology   Vol.37, 1927-1942   2002年

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  • Self-aldol condensation of unmodified aldehydes catalyzed by secondary-amine immobilised in FSM-16 silica

    Tetrahedron Letters   Vol. 43, pp.9073-9075   2002年

  • Stepwize produciton of CO-rich syngas and hydrogen via solar methane reforming by using a Ni(II)-ferrite redox system

    Solar Energy   Vol. 73, No. 5, pp. 363-374   2002年

  • Role of Intracrystalline Tunnels of Sepiolite for Catalytic Activity

    Studies in Surface Science and Catalysis   Vol.142, pp.675-682   2002年

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  • Selective Oxidation of Liquid Hydrocarbons over Photoirradiated TiO<sub>2</sub> Pillared Clays

    Applied Catalysis A: General   Vol.225, pp185-191   2002年

  • Stereoselective Hydrogenation of Linoleic Acid over Ir/FSM-16 Catalyst

    Applied Catalysis A: General   Vol.228, pp.75-82   2002年

  • Stereoselective hydrogenation of linoleic acid over Ir/FSM-16 catalyst

    Ken-ichi Shimizu, Toshiki Kan-no, Tsuyoshi Hatamachi, Shin-ichi Komai, Tatsuya Kodama, Yoshie Kitayama

    Applied Catalysis A: General   228 ( 1-2 )   75 - 82   2002年

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    記述言語:英語  

    Ir/FSM-16 catalysts, prepared by the impregnation method, were investigated in the selective hydrogenation of linoleic acid (cis-9, cis-12 18:2). The results of various characterizations (X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 sorption and X-ray photoelectron spectra (XPS)) indicated that Ir/FSM-16 catalysts contain Ir particles located to a large extent within the FSM-16 channels. For the catalytic hydrogenation of linoleic acid, the Ir/FSM-16 catalyst with relatively higher Ir loading (20 wt.%) produced cis-monoenoic acids (cis 18:1), while dienoic isomers mostly with trans configuration were predominantly produced over Ir supported on non-porous SiO2. The cis/trans ratio of monoenoic acids for the former catalyst was four times larger than that for the latter catalysts. The observed stereoselectivity may be due to an inhibition of the geometric isomerization by the limited space between Ir particles and pore wall of FSM-16. © 2002 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0926-860X(01)00954-1

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  • Suzuki cross-coupling reaction catalyzed by palladium-supported sepiolite

    Tetrahedron Letters   Vol.43, pp.5653-5655   2002年

  • Catalytic direct 1,4-conjugate addition of aldehydes to vinylketones on secondary-amines immobilised in FSM-16 silica

    K Shimizu, H Suzuki, E Hayashi, T Kodama, Y Tsuchiya, H Hagiwara, Y Kitayama

    CHEMICAL COMMUNICATIONS   pp.1068-1069 ( 10 )   1068 - 1069   2002年

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    Direct 1,4-conjugate addition of naked aldehydes to vinylketones is catalysed effectively by N-methyl-3-aminopropylated FSM-16 mesoporous silica, which can be regarded as a novel heterogeneous catalysis for a practical C-C bond formation reaction.

    DOI: 10.1039/b202488h

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  • Catalytic direct 1,4-conjugate addition of aldehydes to vinylketones on secondary-amines immobilised in FSM-16 silica

    K Shimizu, H Suzuki, E Hayashi, T Kodama, Y Tsuchiya, H Hagiwara, Y Kitayama

    CHEMICAL COMMUNICATIONS   pp.1068-1069 ( 10 )   1068 - 1069   2002年

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    Direct 1,4-conjugate addition of naked aldehydes to vinylketones is catalysed effectively by N-methyl-3-aminopropylated FSM-16 mesoporous silica, which can be regarded as a novel heterogeneous catalysis for a practical C-C bond formation reaction.

    DOI: 10.1039/b202488h

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  • Synthesis and Photocatalytic Activity of Titania Pillared Clays

    Journal of Porous Materials   Vol.8, pp.295-301   2001年12月

  • Kinetics of metal oxide-catalyzed CO2 gasification of coal in a fluidized-bed reactor for solar thermochemical process

    T Kodama, A Funatoh, K Shimizu, Y Kitayama

    ENERGY & FUELS   15 ( 5 )   1200 - 1206   2001年9月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Metal oxide-catalyzed CO2 gasification of coal was examined in a small-scale fluidized-bed reactor at 1073-1223 K and at atmospheric pressure, for the purpose of converting solar high-temperature heat to chemical fuels. The metal oxide powder of In2O3, ZnO, or Fe2O3 in the grain sizes of 4-9 mum was simply mixed with the ground bituminous coal (grain size &lt; 300 mum) and the catalytic effects of the metal oxide on the Boudouard reaction (C-CO2 reaction) in the coal gasification were kinetically studied. The initial coal gasification rate followed the homogeneous or shrinking core model. Gasification activity followed the order of In2O3 &gt; ZnO &gt; Fe2O3 at high temperatures above 1123 K while the order changed to In2O3 &gt; Fe2O3 &gt; ZnO at lower temperatures. The comparison on the Arrhenius parameters for the catalytic and noncatalytic gasification suggests that the gas species of In2O(g) and Zn(g) are the intermediates to react with CO2 in the cases of the In2O3- and ZnO-catalyzed gasifications, respectively. High-temperature separation of used ZnO catalyst from the remaining coal ash by Zn evaporation was demonstrated at 1423 K.

    DOI: 10.1021/ef0100404

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  • Kinetics of metal oxide-catalyzed CO2 gasification of coal in a fluidized-bed reactor for solar thermochemical process

    T Kodama, A Funatoh, K Shimizu, Y Kitayama

    ENERGY & FUELS   15 ( 5 )   1200 - 1206   2001年9月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Metal oxide-catalyzed CO2 gasification of coal was examined in a small-scale fluidized-bed reactor at 1073-1223 K and at atmospheric pressure, for the purpose of converting solar high-temperature heat to chemical fuels. The metal oxide powder of In2O3, ZnO, or Fe2O3 in the grain sizes of 4-9 mum was simply mixed with the ground bituminous coal (grain size &lt; 300 mum) and the catalytic effects of the metal oxide on the Boudouard reaction (C-CO2 reaction) in the coal gasification were kinetically studied. The initial coal gasification rate followed the homogeneous or shrinking core model. Gasification activity followed the order of In2O3 &gt; ZnO &gt; Fe2O3 at high temperatures above 1123 K while the order changed to In2O3 &gt; Fe2O3 &gt; ZnO at lower temperatures. The comparison on the Arrhenius parameters for the catalytic and noncatalytic gasification suggests that the gas species of In2O(g) and Zn(g) are the intermediates to react with CO2 in the cases of the In2O3- and ZnO-catalyzed gasifications, respectively. High-temperature separation of used ZnO catalyst from the remaining coal ash by Zn evaporation was demonstrated at 1423 K.

    DOI: 10.1021/ef0100404

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  • Selective exchange and fixation of strontium ions with ultrafine Na-4-mica

    T Kodama, Y Harada, M Ueda, K Shimizu, K Shuto, S Komarneni

    LANGMUIR   17 ( 16 )   4881 - 4886   2001年8月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    A simple preparation process of Na-4-mica (ideal brittle mica composition of Na4Mg6Al4Si4O20F4. xH(2)O) from kaolinite yielded a nearly pure and very fine Na-4-mica with a crystallite size of about 0.2 um. Strontium-sodium ion exchange in the hydrated interlayers of the Na-4-mica was demonstrated with this fine mica. The forward ion exchange of Sr2+ --&gt; 2Na(+) (Sr-ion adsorption) was determined after equilibration for 4 weeks, and the Sr exchange capacity reached a value of about 200 mequiv (100 g)(-1). The parabolic diffusion or modified Freundlich model described the forward exchange process well. Only a small reverse exchange 2Na(+) --&gt; Sr2+ (Sr-ion desorption) occurred from the hydrated Sr2+-saturated sample in 4 weeks. The irreversible sodium-strontium ion-exchange isotherm was obtained at room temperature after 4 weeks of equilibration. This mica showed much higher selectivities for Sr and Ba than for Mg and Ca, as expected. This selective Sr-ion exchanger with a large ion-exchange capacity and extremely low Sr leachability is expected to be useful for Sr-90 removal followed by its immobilization at room temperature.

    DOI: 10.1021/la001774w

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  • 各種セビオライト中の炭酸塩の除去および不純物イオンの置換サイト

    粘土科学   Vol.41, pp.9-15   2001年7月

  • Synthesis of titania pillared mica in aqueous solution of acetic acid

    T Kaneko, M Fujii, T Kodama, Y Kitayama

    JOURNAL OF POROUS MATERIALS   8 ( 2 )   99 - 109   2001年3月

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    記述言語:英語   出版者・発行元:KLUWER ACADEMIC PUBL  

    The preparation of TiO2-pillared mica was carried out in a CH3COOH aqueous solution. Titanium ion species were obtained by an addition of Ti(C3H7O4 to an aqueous solution of CH3COOH and by subsequent aging of the solution for a prescribed time followed by intercalation of these ionic species into the interlayers of mica. Ti4+-intercalated mica was thus obtained by ion exchange. After the sample was calcined at 773 K in air, TiO2-pillared mica was produced. The pillaring of TiO2 in the interlayer of mica was confirmed by XPS. The surface area TiO2-pillared mica was about 100 times larger than that of mica alone. The basal spacings of the products heated above 523 K were in the range from 2.01 nm to 2.68 nm in the samples obtained under various conditions.

    DOI: 10.1023/A:1009634506284

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  • Thermochemical conversion of CH4 to C-2-hydrocarbons and H-2 over SnO2/Fe3O4/SiO2 in methane - Water co-feed system

    T Shimizu, Y Kitayama, T Kodama

    ENERGY & FUELS   15 ( 2 )   463 - 469   2001年3月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Highly endothermic conversion of methane to C-2-hydrocarbons and hydrogen was catalytically demonstrated over the SnO2/Fe3O4/SiO2 at 1173 K under co-feeding of methane and steam. The main products were C2H4, C2H6, CO, CO2, and hydrogen. At a low W/F value (a high GHSV), methane was selectively converted to C-2-hydrocarbons and hydrogen, while at a high W/F value (a low GHSV), steam reforming of methane to produce CO and hydrogen became dominant. At the GHSV = 4000-12000 h(-1), 87-94% of C-2 selectivity with 4-6% of methane conversion was obtained at the C-2-formation rate = 4-8 mmol-C h(-1) g(-1)-cat. This process offers the efficient conversion of natural gas to C-2-hydrocarbon and hydrogen utilizing high-temperature heat such as concentrated solar radiation below 1173 K.

    DOI: 10.1021/ef000200w

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  • Thermochemical conversion of CH4 to C-2-hydrocarbons and H-2 over SnO2/Fe3O4/SiO2 in methane - Water co-feed system

    T Shimizu, Y Kitayama, T Kodama

    ENERGY & FUELS   15 ( 2 )   463 - 469   2001年3月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Highly endothermic conversion of methane to C-2-hydrocarbons and hydrogen was catalytically demonstrated over the SnO2/Fe3O4/SiO2 at 1173 K under co-feeding of methane and steam. The main products were C2H4, C2H6, CO, CO2, and hydrogen. At a low W/F value (a high GHSV), methane was selectively converted to C-2-hydrocarbons and hydrogen, while at a high W/F value (a low GHSV), steam reforming of methane to produce CO and hydrogen became dominant. At the GHSV = 4000-12000 h(-1), 87-94% of C-2 selectivity with 4-6% of methane conversion was obtained at the C-2-formation rate = 4-8 mmol-C h(-1) g(-1)-cat. This process offers the efficient conversion of natural gas to C-2-hydrocarbon and hydrogen utilizing high-temperature heat such as concentrated solar radiation below 1173 K.

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  • CO<sub>2</sub> Reforming of Methane in Molten Carbonate Salt Bath for Use in Solar Thermochemical Processes

    Energy & Fuels   15   60・65   2001年

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  • Selective Exchange and Fixation of Strontium Ions with Ultrafine Na-4-mica

    Langmuir   17巻 4881-4886頁   2001年

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  • Thermochemical methane reforming using WO3 as an oxidant below 1173 K by a solar furnace simulator

    T Shimizu, K Shimizu, Y Kitayama, T Kodama

    SOLAR ENERGY   71 ( 5 )   315 - 324   2001年

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Thermochemical methane reforming by a reactive redox system of WO, was demonstrated under direct irradiation of the metal oxide by a concentrated, solar-simulated Xe-lamp beam below 1173 K, for the purpose of converting solar high-temperature heat to chemical fuels. In the proposed cycling redox process, the metal oxide is expected to react with methane as an oxidant to produce syngas with a H-2/CO ratio of two, which is suitable for the production of methanol, and the reduced metal oxide which is oxidized back with steam in a separate step to generate hydrogen uncontaminated with carbon oxide. The ZrO2-supported WO3 gave about 45% of CO yield and 55% of H-2 yield with a H-2/CO ratio of about 2.4 in a temperature range of 1080-1160 K at a W/F ratio of 0.167 g min Ncm(-3) (W is the weight of WO3 phase and F is the flow rate of CHO. The activity data under the solar simulation were compared to those for the WO3/ZrO2 heated by irradiation of an infrared light. This comparison indicated that the CO selectivity was much improved to 76-85% in the solar-simulated methane reforming, probably by photochemical effect due to WO, phase. The main solid product of WO2 in the reduced WO3/ZrO2 was reoxidized to WO3 with steam to generate hydrogen below 1173 K. (C) 2001 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0038-092X(01)00058-5

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  • Thermochemical methane reforming using WO3 as an oxidant below 1173 K by a solar furnace simulator

    T Shimizu, K Shimizu, Y Kitayama, T Kodama

    SOLAR ENERGY   71 ( 5 )   315 - 324   2001年

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Thermochemical methane reforming by a reactive redox system of WO, was demonstrated under direct irradiation of the metal oxide by a concentrated, solar-simulated Xe-lamp beam below 1173 K, for the purpose of converting solar high-temperature heat to chemical fuels. In the proposed cycling redox process, the metal oxide is expected to react with methane as an oxidant to produce syngas with a H-2/CO ratio of two, which is suitable for the production of methanol, and the reduced metal oxide which is oxidized back with steam in a separate step to generate hydrogen uncontaminated with carbon oxide. The ZrO2-supported WO3 gave about 45% of CO yield and 55% of H-2 yield with a H-2/CO ratio of about 2.4 in a temperature range of 1080-1160 K at a W/F ratio of 0.167 g min Ncm(-3) (W is the weight of WO3 phase and F is the flow rate of CHO. The activity data under the solar simulation were compared to those for the WO3/ZrO2 heated by irradiation of an infrared light. This comparison indicated that the CO selectivity was much improved to 76-85% in the solar-simulated methane reforming, probably by photochemical effect due to WO, phase. The main solid product of WO2 in the reduced WO3/ZrO2 was reoxidized to WO3 with steam to generate hydrogen below 1173 K. (C) 2001 Elsevier Science Ltd. All rights reserved.

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  • Thermochemical Methane Reforming Using WO<sub>3</sub> as An Oxidant below 1173 K by Solar Furnace Simulator

    Solar Energy   Vol. 71, No. 5, pp. 315-324   2001年

  • Synthesis of Na-2-mica from metakaolin and its cation exchange properties

    T Kodama, T Higuchi, T Shimizu, K Shimizu, S Komarneni, W Hoffbauer, H Schneider

    JOURNAL OF MATERIALS CHEMISTRY   11 ( 8 )   2072 - 2077   2001年

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    Na-2-mica of the ideal composition of Na2Mg6Al2Si6O20F4. xH(2)O was prepared from a mixture of NaF, magnesium nitrate, SiO2 and calcined kaolinite (the latter serving as a cost-effective aluminosilicate source) at 800 degreesC and was found to excel in Sr removal from solutions at room temperature. This mica was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and Al-27 and Si-29 magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. Fundamental studies of nNa(+) --&gt; Mn+ (Mn+ = Sr2+, Ca2+, Li+, K+ and Cs+) equilibria revealed a high selectivity and large capacity for Sr2+ ion uptake. A relatively low-temperature heat treatment (200 degreesC) of the Sr-exchanged mica resulted in collapse of the hydrated interlayer spacings of the mica, which will be useful to immobilize strontium in the stable unhydrated phase. This selective Sr-ion exchanger is expected to be useful for Sr-90 removal and its immobilization.

    DOI: 10.1039/b101186n

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  • Synthesis of Na-2-mica from metakaolin and its cation exchange properties

    J. Mater. Chem.   Vol. 11, pp. 2072-2077   2001年

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  • Crystal-size control and characterization of Na-4-mica prepared from kaolinite

    T Kodama, Y Harada, M Ueda, K Shimizu, K Shuto, S Komarneni, W Hoffbauer, H Schneider

    JOURNAL OF MATERIALS CHEMISTRY   11 ( 4 )   1222 - 1227   2001年

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    A simple and economical method for the synthesis of high-charge-density Na-4-mica (ideal chemical composition of Na4Mg6Al4Si4O20F4. xH(2)O) from kaolinite was investigated. Synthesis conditions were varied to control crystal size. This novel swelling Na-4-mica was synthesized from a mixture of kaolinite, magnesium nitrate (or ultrafine MgO) and NaF at 850 degreesC, and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), particle size analysis by laser diffraction and Al-27 and Si-29 magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. Decreasing the mass of NaF flux during the crystallization of Na-4-mica reduced the crystallite size from 2 to 0.2 mum. As the crystallite size decreased, the average particle size of the mica decreased from 5 to 2 mum. Al-27 MAS-NMR spectra showed that all or nearly all Al is in tetrahedral coordination whereas Si-29 MAS-NMR spectra showed that the nearest neighbour environment of Si is mainly in Si(3Al), as expected based on the Si:Al ratio.

    DOI: 10.1039/b009418h

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  • Crystal-size control and characterization of Na-4-mica prepared from kaolinite

    J. Mater. Chem.   Vol. 11, pp. 1222-1227   2001年

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  • Synthesis and Photocatalytic Activity of Titania Pillared Clays

    Journal of Porous Materials   Vol.8, pp.295-301   2001年

  • CO<sub>2</sub> Reforming of Methane in a Molten Carbonate Salt Bath for Use in Solar Thermochemical Processes

    Energy & Fuels   Vol. 15, pp. 60-65   2001年

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  • Metal-oxide-catalyzed CO2 gasification of coal using a solar furnace

    T Kodama, A Funatoh, T Shimizu, Y Kitayama

    ENERGY & FUELS   14 ( 6 )   1323 - 1330   2000年11月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Metal-oxide-catalyzed CO2 gasification of coal was demonstrated in small packed-bed and fluidized-bed reactors using a solar furnace simulator, for the purpose of converting solar high-temperature heat to chemical fuels. The catalytic activities of In2O3 and ZnO were investigated because used In2O3 or ZnO catalyst may be separated from remaining coal ash by In2O or Zn evaporation at high temperatures and at a reducing atmosphere. Bituminous coal with or without the metal-oxide catalyst in the quartz-tube reactor was directly irradiated by the concentrated Xe-lamp beam and CO2 was fed to the reactor at pCO(2) = 1.0. In the packed-bed reactor, In2O3 and ZnO much improved the chemical coal conversion by about 4-5 and 2-3 times at the catalyst loading of 17 wt %-In and 30 wt %-Zn in the coal-metal-oxide mixture, respectively, at temperatures around 1000-1400 K. In the fluidized-bed reactor at a small catalyst loading (8-10 wt %-metal in the coal-metal-oxide mixture) and at 1073-1163 K, In2O3 catalytically increased the coal-conversion rate by 3 times but ZnO scarcely showed the catalytic activity. This metal-catalyzed coal gasification process offers the efficient solar production of the syngas calorifically upgraded by solar energy.

    DOI: 10.1021/ef000169y

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  • Metal-oxide-catalyzed CO2 gasification of coal using a solar furnace

    T Kodama, A Funatoh, T Shimizu, Y Kitayama

    ENERGY & FUELS   14 ( 6 )   1323 - 1330   2000年11月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Metal-oxide-catalyzed CO2 gasification of coal was demonstrated in small packed-bed and fluidized-bed reactors using a solar furnace simulator, for the purpose of converting solar high-temperature heat to chemical fuels. The catalytic activities of In2O3 and ZnO were investigated because used In2O3 or ZnO catalyst may be separated from remaining coal ash by In2O or Zn evaporation at high temperatures and at a reducing atmosphere. Bituminous coal with or without the metal-oxide catalyst in the quartz-tube reactor was directly irradiated by the concentrated Xe-lamp beam and CO2 was fed to the reactor at pCO(2) = 1.0. In the packed-bed reactor, In2O3 and ZnO much improved the chemical coal conversion by about 4-5 and 2-3 times at the catalyst loading of 17 wt %-In and 30 wt %-Zn in the coal-metal-oxide mixture, respectively, at temperatures around 1000-1400 K. In the fluidized-bed reactor at a small catalyst loading (8-10 wt %-metal in the coal-metal-oxide mixture) and at 1073-1163 K, In2O3 catalytically increased the coal-conversion rate by 3 times but ZnO scarcely showed the catalytic activity. This metal-catalyzed coal gasification process offers the efficient solar production of the syngas calorifically upgraded by solar energy.

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  • Thermochemical methane reforming using a reactive WO3/W redox system

    T Kodama, H Ohtake, S Matsumoto, A Aoki, T Shimizu, Y Kitayama

    ENERGY   25 ( 5 )   411 - 425   2000年5月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The methane reforming process combined with metal oxide reduction was evaluated, for the purpose of converting solar high-temperature heat to chemicals below 1273 K. The metal oxide was endothermically reacted with methane, to produce CO, hydrogen and the component metal in the temperature range of 1173-1273 K. Of the metal oxide candidates, WO3 and V2O5 were found to be reactive and selective metal oxides for the purposes of methane reforming. The metallic tungsten produced by methane reforming could be used to split water and to generate hydrogen at a lower temperature of 1073 K. To improve the reactivities of WO3 for methane reforming and the subsequent splitting of water, supported tungsten oxides were examined in the temperature range of 1073-1273 K. The reactivities were much improved with the ZrO2-supported WO3, giving a methane conversion of 70% and a CO selectivity of 86%. Our findings indicate the possibility that the proposed two-step process using a WO3/W redox system may be a potentially new thermochemical path that produces useful energy carriers of processed metal, syngas and methanol for storing and transporting solar energy from the sun belt to remote population centers. (C) 2000 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0360-5442(99)00084-5

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  • Reactive metal-oxide redox system for a two-step thermochemical conversion of coal and water to CO and H-2

    A Aoki, H Ohtake, T Shimizu, Y Kitayama, T Kodama

    ENERGY   25 ( 3 )   201 - 218   2000年3月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A number of metal-oxide redox systems were examined for a two-step thermochemical conversion of coal and water to CO and H-2 for the purpose of utilizing solar high-temperature heat below 900 degrees C: metal oxide+CHn (coal)--&gt;metal+CO+n/2H(2), metal+H2O--&gt;metal oxide+H-2. In2O3 and SnO2 were found to be the most reactive oxidants for coal under an N-2 gas stream below 900 degrees C. These reactive metal oxides were tested for the proposed two-step cyclic process in the pulse feeding mode of H2O, with a temperature swing and under an N-2 gas stream. The two-step cyclic process using the In2O3/coal mixture could be repeated with high coal conversions of about 80% in the temperature range of 600-900 degrees C by resupplying the consumed coal to the system. The repeated two-step process via the In2O3/In redox system resulted in efficient performance of the net reaction CHn (coal)+H2O--&gt;CO+(n/2+1)H-2, while hydrogen was scarcely produced in the continuous feeding mode of H2O/N-2 over the In2O3/coal mixture, at a constant temperature of 900 degrees C. The separation of recovered In2O3 from the remaining coal ashes by In2O evaporation was also proposed, (C) 2000 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0360-5442(99)00067-5

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  • Synthetic clay excels in 90Sr removal

    J. Mater. Res.   Vol. 15, No. 6, pp. 1254-1256   2000年

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  • Na-4-mica: simplified synthesis from kaolinite, characterizaiton and Zn, Cd, Pb, Cu and Ba uptake kinetics

    J. Meter. Chem.   Vol. 10, pp. 1649-1653   2000年

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  • Simplified synthesis of Na-4-mica from kaolinite and its cation-exchange properties

    T Kodama, S Komarneni

    SEPARATION SCIENCE AND TECHNOLOGY   35 ( 8 )   1133 - 1152   2000年

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    記述言語:英語   出版者・発行元:TAYLOR & FRANCIS INC  

    The synthetic process of a high-charge-density sodium fluorophlogopite mica, Na-4-mica (with an ideal chemical composition of Na4Mg6Al4Si4O20F4. nH(2)O), using kaolinite as a raw material, has been investigated with respect to developing a simplified procedure and controlling crystal size. A fine and highly crystalline phase of the hydrated Na-4-mica, which is essential for practical applications, could be easily prepared from a mixture of kaolinite (or metakaolin) and magnesium nitrate using NaF flux at temperatures below 800 degrees C. An increased mass of NaF flux in the simplified process at 800 degrees C yielded somewhat larger and well-dispersed Na-4-mica crystals with hexagonal and plate-like shapes of 2-3 mu m in size. Cation-exchange equilibria was studied for alkaline earth metal ions of Sr, Ba, and Ca, as well as transition metal ions of Cu and Pb, at room temperature using the hydrated Na-4-mica synthesized by the simplified process. The order of selectivity for the alkaline earth metal ions was Ba2+ &gt;&gt; Sr2+ &gt; Ca2+, and the cation-exchange capacities were 197, 83, and 77 mequiv (100 g)(-1), respectively.

    DOI: 10.1081/SS-100100216

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  • Simplified Synthesis of Na-4-mica from Kaolinite and Its Cation-exchange Properties

    Separation Science and Technology   Vol. 35, No. 8, pp. 1133-1152   2000年

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  • Synthetic clay excels in <sup>90</sup>Sr removal

    J. Mater. Res.   15   1254 - 1256   2000年

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  • Thermochemical methane reforming using a reactive WO<sub>3</sub>/W redox System

    Energy   Vol. 25, pp. 411-425   2000年

  • Reactive metal-oxide redox system for a two-step tehrmochemical conversion of coal and water to CO and H<sub>2</sub>

    Energy   Vol. 25, pp. 201-218   2000年

  • Thermochemical CO<sub>2</sub> Gasification of Cool Using a Reactive Cool-In<sub>2</sub>O<sub>3</sub> System

    Energy&Fuels   14 ( 1 )   202 - 211   2000年

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  • Thermochemical CO<sub>2</sub> Gasification of Coal Using a Reactive Coal-In<sub>2</sub>O<sub>3</sub> System

    Energy & Fuels   Vol. 14, pp. 202-211   2000年

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  • Na-4-mica : simplified synthesis from kaolinite, characterization and Zn, Cd, Pb, Cu and Ba uptake kinetics

    J. Mater. Chem.   10 ( 7 )   1649 - 1653   2000年

  • Cyclodehydration of diethylene glycol (DEG) catalyzed by clay mineral sepiolite

    Y Kitayama, M Kamimura, K Wakui, M Kanamori, T Kodama, J Abe

    JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL   142 ( 2 )   237 - 245   1999年6月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE BV  

    Clay mineral sepiolite exhibited high selectivity for the catalytic conversion of diethylene glycol (DEG) into 1,4-dioxane. The selectivity for the 1,4-dioxane formation depended on weight hourly space velocity (WHSV) and the tunnel structure of sepiolite. When an excess DEG was supplied over the adsorption capacity of the tunnels in sepiolite, the selectivity for 1,4-dioxane formation from DEG decreased and by-products formation increased. These results indicate that cyclodehydration of DEG takes place in the internal space of the intracrystalline tunnels of sepiolite and by-products formation occurs on the outer surface of sepiolite. The Mg(II) ion along the tunnel wall of sepiolite acts as an active site for the cyclodehydration. (C) 1999 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S1381-1169(98)00290-8

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  • A reactive redox system of metal oxide for a two-step thermochemical cycle for converting coal to upgraded chemical fuels of CO/H-2

    T Kodama, T Shimizu, A Aoki, Y Kitayama

    JOURNAL DE PHYSIQUE IV   9 ( P3 )   343 - 348   1999年3月

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    記述言語:英語   出版者・発行元:E D P SCIENCES  

    A two-step thermochemical process using a redox system of metal oxides for converting coal to CO and H-2 with H2O/CO2 was studied for the propose of utilizing solar high-temperature heat below 1173 K. In the first step, metal oxide was reacted with coal as an oxidant to produce CO and H-2: metal oxide + CHn(coal) --&gt; metal + xCO + (l-x)CO2 + n/2H(2). The metal so formed was reoxidized with H2O or CO2 to generate H-2 or CO in the second step. A number of coal-metal oxide systems were thermodynamically examined and demonstrated at 1173 K. The coal-In2O3 and coal-SnO systems yielded 82 and 62%, respectively. With iron-based oxides, the In(III)-, Ni(II)- and Sn(II)-doped ferrites yielded 60-70% of coal conversions. In these coal-ferrite systems, magnetic separation of recovered ferrite from coal ashes can be expected. The proposed two-step process using In(III)-ferrite could be repeated with highly coal conversion of 60-90%. Our two-step process is superior to the conversions of coal and H2O/CO2 to H-2 and CO below 1173 K by the direct single-step reactions, CHn + H2O --&gt; CO + (n/2+1)H-2 and CHn + CO2 --&gt; 2CO + n/2H(2).

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  • A two-step thermochemical conversion of CH4 to CO, H-2 and C-2-hydrocarbons below 1173 K

    A Aoki, T Shimizu, Y Kitayama, T Kodama

    JOURNAL DE PHYSIQUE IV   9 ( P3 )   337 - 342   1999年3月

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    記述言語:英語   出版者・発行元:E D P SCIENCES  

    A high-temperature thermochemical process using a redox system of metal oxide is proposed for converting CH4 to CO, H-2, and C-2-hydrocarbons (C-2-HCs). Reactions were performed in a two-step redox cycle. In the first high-temperature and endothermic step, methane is reacted with metal oxide to produce C2-HCs and the reduced metal oxide:
    2CH(4)+ metal oxide --&gt; C2Hn + (4-n/2)H2O + reduced metal oxide
    In the second step, H2O or CO2 is reacted with the reduced metal oxide to generate H-2 or CO at lower temperatures:
    H2O + reduced metal oxide --&gt; H-2 + metal oxide
    CO2 + reduced metal oxide --&gt; CO + metal oxide
    The net reactions are 2CH(4) --&gt; C2H(n) + (4-n/2)H-2, and 2CH(4) + (4-n/2)CO2 --&gt; C2Hn + (4-n/2)(CO + H2O). A thermodynamic analysis showed that redox systems of Fe3O4/FeO, SnO2/SnO and WO3/WO2 are promising for the two-step process. The redox system of Fe3O4 was experimentally examined. Methane was selectively converted to C-2-HCs, H-2, and CO by the two-step process using the Sig-supported Fe3O4 (Fe3O4/SiO2) in the temperature range from 1123 to 1173 K. It was found that the high-temperature methane decomposition to bulk carbon was efficiently suppressed over Fe3O4/SiO2 This process offers the efficient endothermic net reaction for converting natural gas to C2H4, H-2, and CO with upgraded calorific values. utilizing concentrated solar radiation as the energy source of high-temperature process heat below 1173 K.

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  • A two-step thermochemical conversion of CH<sub>4</sub> to CO, H<sub>2</sub> and C<sub>2</sub>-hydrocarbons below 1173 K

    J. Phys. IV France   Vol. 9, Pr3-337-342   1999年

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  • Na-4-mica: Cd<sup>2+</sup>, Ni<sup>2+</sup>, Co<sup>2+</sup>, Mn<sup>2+</sup>, Zn<sup>2+</sup> ion exchange

    J. Mater. Chem.   Vol. 9, pp. 533-539   1999年

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  • A reactive redox system of metal oxide for a two-step thermochemical cycle for converting coal to upgraded chemical fuels of CO/H<sub>2</sub>

    J. Phys. IV France   Vol. 9, Pr3-343-348   1999年

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  • Selective Cu<sup>2+</sup> and Pb<sup>2+</sup> exchange with highly charged cation exchanger of Na-4-mica

    Separation Science and Technology   Vol. 34, No. 12, pp. 2275-2292   1999年

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  • Na-4-mica: Cd2+, Ni2+, Co2+, Mn2+ and Zn2+ ion exchange

    Tatsuya Kodama, Sridhar Komarneni

    Journal of Materials Chemistry   9 ( 2 )   533 - 539   1999年

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    記述言語:英語  

    Selective cation exchange for divalent transition metals of Cd, Ni, Co, Mn and Zn has been investigated with the high-charge-density sodium fluorophlogopite mica, Na-4-mica. The Na-4-mica was easily and economically prepared by the crystallization from a mixture of NaF, MgO and metakaolin, the latter serves as an inexpensive aluminosilicate source. Ion exchange isotherms for Cd2+, Ni2+, Co2+, Mn2+ and Zn2+ were obtained at room temperature and the thermodynamic functions of the ion exchange equilibria were calculated. The 2Na+ → M2+ exchange with the Na-4-mica showed the following selectivity: Zn2+ &gt
    Ni2+ ≃Co2+ ≃Cd2+ &gt
    Mn2+. The interlayer structure of the hydrated Na-4-mica with the open interlayer space in the range 12.1-13.9 Å was retained during the ion-exchange reaction, indicating the possibility of the reversible 2Na+ ⇆M2+ exchange. The basic selective cation exchange studies of the high-charge-density ion exchanger are of relevance in recovery of metals from waste solution, and waste water treatment and disposal.

    DOI: 10.1039/a806758i

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  • Alkali-Metal and Alkaline Earth Metal Ion Exchange with Na-4-Mica prepared by a New Synthetic Route from Kaolinite

    J. Mater. Chem.   9 ( 10 )   2475 - 2480   1999年

  • Alkali metal and alkaline earth ion exchange with Na-4-mica prepared by a new synthetic route from kaolinite

    J. Mater. Chem.   Vol. 9, pp. 2475-2480   1999年

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  • Selective Cu2+ and Pb2+ exchange with highly charged cation exchanger of Na-4-mica

    T Kodama, S Komarneni

    SEPARATION SCIENCE AND TECHNOLOGY   34 ( 12 )   2275 - 2292   1999年

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    記述言語:英語   出版者・発行元:TAYLOR & FRANCIS INC  

    Selective cation exchange for Cu and Pb has been demonstrated with the high-charge-density sodium fluorophlogopite mica, Na-4-mica. The 2Na(+) --&gt; M2+ exchange reaction (M = Cu or Pb) was investigated with Na-4-micas prepared by two different synthetic processes. One was easily and economically prepared by crystallization from a mixture of NaF, MgO, and metakaolin, the latter serves as an inexpensive aluminosilicate source. Another was prepared by solution-sol-gel processing. Ion-exchange isotherms for Cu2+ and Pb2+ were obtained at room temperature. The thermodynamic functions for the initial ion-exchange reactions were calculated because the isotherms were not completed. High selectivities for both copper and lead exchange were found on the highly crystallized Na-4-mica prepared from metakaolin. Their ion-exchange capacities were 225 and 257 milliequivalents per 100 g of dry clay for Cu2+ and Pb2+, respectively. This high level decontamination of copper and lead with the highly crystallized Na-4-mica from metakaolin will be a very important separation required for purification of drinking water as well as for wastewater treatment and disposal.

    DOI: 10.1081/SS-100100772

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  • Structure refinement of lithium ion conductors Li3Sc2(PO4)(3) and Li3-2x(Sc1-xMx)(2)(PO4)(3) (M = Ti, Zr) with x = 0.10 by neutron diffraction

    T Suzuki, K Yoshida, K Uematsu, T Kodama, K Toda, ZG Ye, M Ohashi, M Sato

    SOLID STATE IONICS   113   89 - 96   1998年12月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE BV  

    The crystal structure of lithium ion conductors, Li3Sc2(PO4)(3) and Li3-2x(Sc1-xMx)(2)(PO4)(3) (M = Ti, Zr) with x = 0.10, were refined by Rietveld analysis for neutron diffraction patterns in order to confirm the site location and site occupancy for Li ions. The Rietveld refinement confirmed that a high disorder was introduced to three kinds of Li sites in the high temperature superionic conduction phase of Li3Sc2(PO4)(3). The high temperature phase was stabilized at room temperature by substituting Ti4+ or Zr4+ for Sc3+ sites. The stabilized materials were also found to have similar high disorder over the Li sites. (C) 1998 Published by Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0167-2738(98)00279-3

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  • Synthesis of titania pillared saponite in aqueous solution of acetic acid

    Y Kitayama, T Kodama, M Abe, H Shimotsuma, Y Matsuda

    JOURNAL OF POROUS MATERIALS   5 ( 2 )   121 - 126   1998年5月

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    記述言語:英語   出版者・発行元:KLUWER ACADEMIC PUBL  

    The preparation of TiO2-pillared saponite was carried out in a CH3COOH aqueous solution. Titanium ion species to intercalate into the interlayer of saponite were obtained by an addition of Ti(C3H7O)(4) to an aqueous solution of CH3COOH and by subsequent aging of the solution for a prescribed time. Ti4+-intercalated saponite including organic materials was obtained by ion exchange. After the sample was calcined at 500 degrees C in air, TiO2-pillared saponite was obtained. The resulting TiO2-pillared saponite (Ti-Sapo) possessed surface areas in the range 300-400 m(2)/g and a sharp pore size distribution with the pore radius of 1.2 nm, The basal spacing of the product heated at temperature &gt;250 degrees C was about 2.45 nm. The pillar height of TiO2 in the Ti-Sapo was estimated to be 1.5 nm.

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  • Synthesis of Sn-incorporated folded sheets mesoporous materials (Sn-FSM-16)

    Y Kitayama, H Asano, T Kodama, J Abe, Y Tsuchiya

    JOURNAL OF POROUS MATERIALS   5 ( 2 )   139 - 146   1998年5月

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    記述言語:英語   出版者・発行元:KLUWER ACADEMIC PUBL  

    Sn-incorporated folded sheets mesoporous materials (Sn-FSM-16) with various contents of Sn were synthesized by using a mixture of water glass, SnCl4 and NaOH as starting materials. Hexadecyltrimethyl-ammonium chloride (surfactant) was used to intercalate into the layered silicate. The reaction process was followed by measurements of XRD patterns of intermediates. The Sn-FSM-16 was formed via the following mechanism: (1) layered silicates such as alpha-, beta- and delta-Na2Si2O5 were formed as intermediates by the calcination of the mixture of the starting materials; (2) the surfactant was intercalated into the layered silicates; (3) the surfactant-silicate complex with hexagonal structure was obtained as a precursor of Sn-FSM-16; (4) the precursor was calcined to decompose the surfactant in the interlayer and was changed to Sn-FSM-16. The structural aspect of Sn in Sn-FSM-16 was studied by XPS profiles of Sn 3d(5/2) and Si-2p, Si-29 MAS NMR and FTIR. The content of Sn in Sn-FSM increased with increasing concentrations of both Sn and NaOH in the starting materials. The surface area of Sn-FSM-16 decreased with an increase of Sn content in Sn-FSM (1160-620 m(2)/g).

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  • Efficient two-step tehrmochemical process using highly reactive metal oxides for conversion of high-temperature heat to chemical fuels

    Recent Res. Devel. in Mat. Sci.   Vol. 1, pp. 109-121   1998年

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  • Gas-Liquid Chromatographic Analysis of Geometrical and Positional Octadecenoic and Octadecadienoic Acid Isomers Produced by Catalytic Hydrogenation of Lenoleic Acid or Ir/Al<sub>2</sub>O<sub>3</sub>

    J. Am. Oil Chem. Soc.   75 ( 1 )   27 - 32   1998年

  • Efficient Two-Step Thermochemical Process Using Highly Reactive Metal Oxide for Conversion of High-Temperature Heat to Chemical Fuels

    Recent Res. Devel. in Mat. Sci.   1   109 - 121   1998年

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  • Efficient Thermochemical Cycle for Co<sub>2</sub> Reduction with Coal Using a Reactive Redox System of Ferrite

    Studies in Surface Science and Catalysis   114   383 - 386   1998年

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  • Oxidative Coupling of Methane Using H<sub>2</sub>O as an Oxidant over Ferrite Catalysts

    J. Mag. Soc. Jpn   22 ( S1 )   400 - 402   1998年

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  • New Ferrite Application for a Thermochemical CO<sub>2</sub> Reduction with Coal

    J. Mag. Soc. Jpn   22 ( S1 )   403 - 405   1998年

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  • New Synthesis Method of Ultrafine Ferrite by Reduction of Fe(III)-Tartrate Chelate Solution

    J. Mag. Soc. Jpn   22 ( S1 )   440 - 442   1998年

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  • Efficient Thermochemical Cysle for CO<sub>2</sub> Gasification of Coal Using a Redox System of Reactive Iron-Based Oxide. (Jointly Worked)

    Energy & Fuels   12 ( 4 )   775 - 781   1998年

  • Efficient thermochemical cycle for CO<sub>2</sub> gasification of coal using a redox system of reactive iron-based oxide

    Energy & Fuels   Vol. 12, pp. 775-781   1998年

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  • Thermochemical conversion of coal and water to CO and H-2 by a two-step redox cycle of ferrite

    T Kodama, S Miura, T Shimizu, Y Kitayama

    ENERGY   22 ( 11 )   1019 - 1027   1997年11月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Redox systems of iron-based oxides (ferrites) mixed with coal powder have been studied to determine the most reactive and selective working materials for thermochemical conversion of coal and water to CO and H-2. Reactions were performed in a two-step redox cycle in which the ferrites were reacted with coal powder at 900 degrees C to produce CO, H-2, and reduced ferrites (coal-gasification step); these were then reoxidized with water vapor to generate H-2 at 700 degrees C in a separate step (water-decomposition step). Magnetite and Mg(II)-, Mn(II)-, Ni(II)-, Zn(II)-, and In(III)-ferrites have been screened for reactivity and selectivity in the coal-gasification step. The In(III)-ferrite showed the greatest reactivity and selectivity for CO formation from coal at 900 degrees C. The CO-production rate in the coal-In(III)-ferrite reaction was 3.5 times as fast as that in the single-step direct coal-H2O reaction. The metallic phase of alpha-Fe and In, produced by the coal-In(III)-ferrite reaction, was reoxidized to the ferrite phase to generate I-I, in the water-decomposition step at 700 degrees C. The amount of H-2 evolved using In(III)-ferrite was 5 times larger than that using magnetite. The processes were repeated in the temperature range 700-900 degrees C, with the highly efficient net reaction CHtau(coal) + H2O --&gt; CO + (tau/2 + 1)H-2. (C) 1997 Elsevier Science Ltd.

    DOI: 10.1016/S0360-5442(97)00041-8

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  • High-temperature conversion of CH4 to C-2-hydrocarbons and H-2 using a redox system of metal oxide

    T Kodama, T Shimizu, A Aoki, Y Kitayama

    ENERGY & FUELS   11 ( 6 )   1257 - 1263   1997年11月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    A high-temperature thermochemical process using a redox system of metal oxide is proposed for converting CH4 to C-2-hydrocarbons (C-2-HCs) and H-2. Reactions were performed in a two-step redox cycle. In the first high-temperature and endothermic step, methane is reacted with metal oxide to produce C-2-HCs and the reduced metal oxide. The reduced metal oxideis reoxidized with water to generate H-2 at a low temperature in the second step. A thermodynamic analysis showed that redox systems of Fe3O4/FeO, SnO2/SnO, and WO3/WO2 are promising for the two: step process. The redox system of Fe3O4 was experimentally examined. Highly selective conversion could be repeated with SiO2-supported Fe3O4 (Fe3O4/SiO2) to produce C-2-HCs (mainly C2H4) and H-2 alternately in the different steps at temperatures from 1123 to 1173 K; evolution of COx and deposition of bulk carbon were scarcely observed. Experimental studies using unsupported Fe3O4 showed that the formation of C-2-HCs in the first high-temperature step occurred favorably for the reduction from Fe3O4 to FeO in comparison to that from FeO to alpha-FeO. The two-step process using Fe3O4/SiO2 is superior to the production efficiencies of C-2-HCs and H-2 obtained by the direct single-step conversion of CH4; which offers the efficient conversion of natural gas utilizing high-temperature heat such as concentrated solar radiation.

    DOI: 10.1021/ef9700691

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  • High-temperature conversion of CH4 to C-2-hydrocarbons and H-2 using a redox system of metal oxide

    T Kodama, T Shimizu, A Aoki, Y Kitayama

    ENERGY & FUELS   11 ( 6 )   1257 - 1263   1997年11月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    A high-temperature thermochemical process using a redox system of metal oxide is proposed for converting CH4 to C-2-hydrocarbons (C-2-HCs) and H-2. Reactions were performed in a two-step redox cycle. In the first high-temperature and endothermic step, methane is reacted with metal oxide to produce C-2-HCs and the reduced metal oxide. The reduced metal oxideis reoxidized with water to generate H-2 at a low temperature in the second step. A thermodynamic analysis showed that redox systems of Fe3O4/FeO, SnO2/SnO, and WO3/WO2 are promising for the two: step process. The redox system of Fe3O4 was experimentally examined. Highly selective conversion could be repeated with SiO2-supported Fe3O4 (Fe3O4/SiO2) to produce C-2-HCs (mainly C2H4) and H-2 alternately in the different steps at temperatures from 1123 to 1173 K; evolution of COx and deposition of bulk carbon were scarcely observed. Experimental studies using unsupported Fe3O4 showed that the formation of C-2-HCs in the first high-temperature step occurred favorably for the reduction from Fe3O4 to FeO in comparison to that from FeO to alpha-FeO. The two-step process using Fe3O4/SiO2 is superior to the production efficiencies of C-2-HCs and H-2 obtained by the direct single-step conversion of CH4; which offers the efficient conversion of natural gas utilizing high-temperature heat such as concentrated solar radiation.

    DOI: 10.1021/ef9700691

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  • Methanation of CO<sub>2</sub> Using Ultrafine Ni<sub>x</sub>Fe<sub>3-x</sub>O<sub>4</sub> (Jointly Worked)

    Energy   22 ( 2/3 )   183 - 187   1997年

  • High-temperature reactions of metal oxides of CH<sub>4</sub> with H<sub>2</sub>O to form C<sub>2</sub>H<sub>4</sub>, CO and H<sub>2</sub>

    Energy   Vol. 22, No. 9, pp. 859-866   1997年

  • Thermochemical conversion of coal and water to CO and H<sub>2</sub> by a two-step redox cycle of ferrite

    Energy   Vol. 22, No. 11, 1019-1027   1997年

  • High-Temperature Reactions on Metal Oxides of CH<sub>4</sub> with H<sub>2</sub>O to Form C<sub>2</sub>H<sub>4</sub>, CO and H<sub>2</sub> (Jointly Worked)

    Energy   22 ( 9 )   859 - 866   1997年

  • Reactive and selective redox system of Ni(II)-ferrite for a two-step CO and H-2 production cycle from carbon and water

    T Kodama, Y Watanabe, S Miura, M Sato, Y Kitayama

    ENERGY   21 ( 12 )   1147 - 1156   1996年12月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A number of redox systems composed of carbon and bivalent metal-ferrites, MFe(2)O(4)(M = bivalent metal ions), were studied to find the most reactive and selective working materials for a thermochemical water-decomposition cycle combined with CO production from a carbon compound. Magnetite and Mg(II)-, Mn(II)-, Co(II)-, Ni(II)-, and Zn(II)-ferrites mixed with carbon powder have been screened for reactivity and selectivity in the CO-production step (first step) and subsequent water-decomposition step (second step). The Ni(II)-ferrite showed the most reactivity and selectivity for CO formation from carbon in the first step at temperatures above 700 degrees C. The Ni(II)-ferrite could be completely reduced with carbon to the metallic phase of the Ni-Fe alloy and Ni in the first step although only a small portion of magnetite was reduced to wustite under similar conditions. The ferrites reduced in the first step were oxidized with water vapor to generate H-2 in the second step. The highest conversion of H2O to H-2 was obtained using the Ni(II)-ferrite. The total amount of evolved H-2 using Ni(II)-ferrite was 10 times larger than for the magnetite at 500 degrees C. The processes could be repeated using the phase transition between Ni(II)-ferrite and Ni-Fe alloy in the temperature range 700-800 degrees C, with the highly efficient net reaction H2O + C --&gt; H-2 + CO. Copyright (C) 1996 Elsevier Science Ltd.

    DOI: 10.1016/0360-5442(96)00058-8

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  • セピオライト結晶格子のMg(II)のCu(II)による水溶液中での置換反応(共著)

    北山 淑江, 村岡 雅弘, 児玉 竜也, 尾身 尚弘, 大泉 学

    粘土科学   35 ( 4 )   188 - 191   1996年

  • Preparation and CO<sub>2</sub> Methanation Activity of an Ultrafine Ni(II) Ferrite Catalyst (Jointly Worked)

    Journal of Catalysis   164 ( 2 )   315 - 321   1996年

  • Synthesis and Characterization of Ultrafine Mn(II)-Bearing Ferrite of Type Mn<sub>x</sub>Fe<sub>3-x</sub>O<sub>4</sub> by Co-Precipitation (Jointly Worked)

    Material Research Bulletin   31 ( 12 )   1501 - 1512   1996年

  • Catalytic Acceleration for CO<sub>2</sub> Decomposition into Carbon by Rh, Pt or Ce Impregnation onto Ni(II)-Bearing Ferrite (Jointly Worked)

    Applied Catalysis A   142 ( 1 )   31 - 45   1996年

  • Preparation of large Surface Area Nickel Magnesium Silicate and Its Catalytic Activity for Conversion of Ethanol into Buta-1,3-diene (Jointly Worked)

    Catalysis Letters   36   95   1996年

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  • Characterization of Ultrafine Ni<sub>x</sub>Fe<sub>3-x</sub>O<sub>4</sub> Particles Synthesized by Co-Precipitation : Size Requlation and Magnetic Properties (Jointly Worked)

    T. Kodama, Y. Kitayama, M. Tsuji, Y. Tamaura

    Journal of the Magnetics Society of Japan   20 ( 2 )   305 - 308   1996年

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  • Reactive and selective redox system of Ni(II)-ferrite for a two-step CO and H<sub>2</sub> production cycle from carbon and water

    Energy   Vol. 21, No. 12, pp. 1147-1156   1996年

  • Reaction Condition for the Synthesis of Ultrafine Particles of the High-Vacancy-Content Zn(II)-Bearing Ferrites from Iron(III) Tartrate Solution (Jointly Worked)

    Journal of the American Ceramic Society   78 ( 5 )   1335 - 1342   1995年

  • CO<sub>2</sub> Decomposition to Carbon with Ferrite-Derived Metallic Phase at 300℃ (Jointly Worked)

    Carbon   33 ( 10 )   1443 - 1447   1995年

  • XRD and M(]E88D8[)ssbauer Studies on Oxygen-Deficient Ni(II)-Bearing Ferrite with a High Reactivity for CO<sub>2</sub> Decomposition to Carbon (Jointly Worked)

    Journal of Solid State Chemistry   120 ( 1 )   64 - 69   1995年

  • Synthesis and Characterization of Ultrafine Nickel(II)-bearing Ferrites (Ni<sub>x</sub> Fe<sub>3-x</sub>O<sub>4</sub>, x=0.14-1.0) (Jointly Worked)

    Journal of Materials Chemistry   5 ( 9 )   1413 - 1418   1995年

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  • CO<sub>2</sub> Decomposition to Carbon by Ultrafine Ni(II)-Bearing Ferrite at 300℃(Jointly Worked)

    Materials Research Bulletin   30 ( 8 )   1039 - 1048   1995年

  • Synthesis of Hydrotalcite with High Layer Charge for CO<sub>2</sub> Adsorbent (Jointly Worked)

    Energy Conversion and Management   36 ( 6/9 )   637 - 640   1995年

  • Decomposition of carbon dioxide to carbon by hydrogen-reduced Ni(II)-bearing ferrite

    H. Kato, T. Kodama, M. Tsuji, Y. Tamaura, S. G. Chang

    Journal of Materials Science   29 ( 21 )   5689 - 5692   1994年1月

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    記述言語:英語   出版者・発行元:Kluwer Academic Publishers  

    Hydrogen-activated Ni(II)-bearing ferrite, Ni0.37 2+Fe0.49 2+Fe2.09 3+O4.00, showed a high rate of decomposition of carbon dioxide to carbon at 300°C. This is based on the redox process of the Ni(II)-bearing ferrite with the spinel type of crystal structure. The rates of both activation by hydrogen gas and oxidation in carbon dioxide gas were much improved in the Ni (II)-bearing ferrite. The rate of decomposition was 0.178 mol h-1 for the activated Ni(II)-bearing ferrite and 0.005 92 mol h-1 for the activated magnetite in the batch mode, being 30 times larger. The rate of carbon dioxide decomposition was 16 times higher in the flow system in comparison with that of the activated magnetite. © 1994 Chapman &amp
    Hall.

    DOI: 10.1007/BF00349965

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  • Decomposition of CO<sub>2</sub> to Carbon by H<sub>2</sub>-reduced Ni(II)-and Co(II)-bearing Ferrites at 300℃ (Jointly Worked)

    Journal of Materials Research   9 ( 2 )   462 - 467   1994年

  • Methanation of CO<sub>2</sub> on H<sub>2</sub>-reduced Ni(II)-or Co(II)-bearing Ferrites at 200℃ (Jointly Worked)

    Journal of Materials Science   29 ( 23 )   6227 - 6230   1994年

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  • CO<sub>2</sub> Decomposition with Mangano-Wustite (Jointly Worked)

    Journal of Materials Science   29 ( 4 )   999 - 1003   1994年

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  • Carbon Dioxide Decomposition into Carbon with the Rhodium-bearing Maynetite Activated by H<sub>2</sub>-reduction (Jointly Worked)

    Journal of Materials Science   28 ( 4 )   860 - 864   1993年

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  • Methanation of CO<sub>2</sub> with the H<sub>2</sub>-reduced Magnetite (Jointly Worked)

    Journal of Materials Science   28 ( 5 )   1220 - 1226   1993年

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  • CO<sub>2</sub> Decomposition with Oxygen-deficient Mn(II) Ferrite (Jointly Worked)

    Journal of Materials Science   28 ( 4 )   971 - 974   1993年

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  • Decomposition of CO<sub>2</sub> and CO into Carbon with Active Wustite Prepared from Zn(II)-bearing Ferrite (Jointly Worked)

    Journal of Materials Science   28 ( 2 )   547 - 552   1993年

  • HIGH-VACANCY-CONTENT ZINC(II)-BEARING FERRITES FROM IRON(III) TARTRATE IN STRONGLY ALKALINE-SOLUTIONS

    T KODAMA

    JOURNAL OF MATERIALS CHEMISTRY   2 ( 5 )   525 - 528   1992年5月

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    Zn(II)-bearing ferrites with spinel-type structure have been synthesized in strongly alkaline solutions of iron(III) tartrate containing Zn(II) ions at 100-degrees-C. The Zn(II)-bearing ferrites contain few Fe(II) ions, but have a high cation vacancy content (high-vacancy-content Zn(II)-bearing ferrite). The ferrites are solid solutions represented by x(ZnFe2O4)-y(Fe3O4)-z(gamma-Fe2O3), where x + y + z = 1 (0.16 less-than-or-equal-to x less-than-or-equal-to 0.90, 0.01 less-than-or-equal-to y less-than-or-equal-to 0.02, 0.09 less-than-or-equal-to z less-than-or-equal-to 0.82). The cation vacancies are replaced with the Zn(II) ions in the reaction solution, and the replaced number increases with an increase in the concentration of the Zn(II) ions. The high-vacancy-content Zn(II)-bearing ferrites have an ultrafine particle size, &lt; 20 nm. The crystal growth of the ferrite particles is accelerated with the Zn(II) ions in the reaction solution.

    DOI: 10.1039/jm9920200525

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  • Decomposition of Carbon Dioxide to Carbon with Active Wustite at 300℃ (Jointly Worked)

    Journal of American Ceramic Society   75 ( 5 )   1287 - 1289   1992年

  • Adsorption of CO<sub>2</sub> on Oxygen-deficient Magnetite : Adsorption Enthalpy and Adsorption Isotherm (Jointly Worked)

    Journal of Chemical Society, Faraday Transactions   88 ( 18 )   2771 - 2773   1992年

  • Characterization of Zinc(II)-bearing Ferrites from the Strongly Alkaline Solutions of Fe(III)-tartrate, and Dextrose (Jointly Worked)

    Ceramic Transactions   22   603   1991年

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  • High-vacancy-content ferrite with fine particles

    T. Kodama, T. Itoh, M. Tabata, Y. Tamaura

    Journal of Applied Physics   69 ( 8 )   5915 - 5917   1991年

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    記述言語:英語  

    The high-vacancy-content ferrites represented by x(MFe2O 4)·y(Fe3O4)·z(γ-Fe 2O3), where x+y+z=1 (z≳0.50), were obtained in the clear and strongly alkaline solutions of Fe(III) and M(II) tartrate [M(II)=Zn(II), Ni(II), and Cd(II)] or dextrose at 100°C. The vacancies were replaced with the bivalent metal ions in the reaction solutions, and the replaced number increased with an increase in the concentration of the bivalent metal ions. The ferrite particle size was dependent on the bivalent metal species and the content (x,y). The Fe(II) ions enhanced the crystal-growth rate. The particle size of the magnetites (x=0) increased from 100 to 800 Å with an increase in the Fe(II) ion content (y=0.10-0.35). The high-vacancy-content magnetite was transferred from superparamagnetic to ferrimagnetic particles as the size increased. The Zn(II), Ni(II), and Cd(II) ions did not enhance the growth rate so much as compared to the Fe(II) ions. The particle sizes were less than 200 Å, and most of the particles were superparamagnetic. The saturation magnetizations were lower than the theoretical values, and increased with an increase in the particle size, indicating the surface effect.

    DOI: 10.1063/1.347838

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  • The Formation of High-vacancy-content M(II)-bearing Ferrites (M=Ni and Cd) from the Strongly Alkaline Solutions of Fe(III)-tartrate, and Dextrose (Jointly Worked)

    Ceramic Transactions   22   609   1991年

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  • High-vacancy-content Magnetites and Zinc-bering Ferrites from Iron(III) tartrate in Strongly Alkaline Solution (Jointly Worked)

    Journal of American Ceramic Society   73 ( 8 )   2539 - 2542   1990年

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Works(作品等)

  • Study on solar methane reforming and coal gasificatin to produce hydrogen

    2003年

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  • 反応性セラミックによる集光熱/水素エネルギー転換に関する研究

    1997年

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  • 新規膨潤性マイカのイオン交換に関する研究

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  • 集光太陽熱による天然ガス改質・石炭ガス化による水素製造に関する研究

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  • Study on solar thermochemical water splitting cycle

    1997年

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  • Study on nevel inorganic ion exchangers

    1997年

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受賞

  • 財団 手島工業教育資金団工業技術研究賞

    2002年  

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    受賞国:日本国

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  • 第70春季年会講演奨励賞

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    受賞国:日本国

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共同研究・競争的資金等の研究

  • 無機層状化合物のイオン交換

    1997年

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    資金種別:競争的資金

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  • Study on solar thermochemical water splitting cycle for H<sub>2</sub> production

    1997年

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    資金種別:競争的資金

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  • Study on solar thermochemical, natural-gas reforming and coal gasification to produce hydrogen

    1997年

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    資金種別:競争的資金

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  • Ion Exchange by novel inorganic materials

    1997年

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    資金種別:競争的資金

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  • 水分解熱化学サイクルの研究

    1997年

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    資金種別:競争的資金

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  • 太陽熱による天然ガス改質・石炭ガス化水素製造システムの研究

    1997年

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    資金種別:競争的資金

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