The Experts below are selected from a list of 5898 Experts worldwide ranked by ideXlab platform
Yasukazu Saito - One of the best experts on this subject based on the ideXlab platform.
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Catalytic decalin deHydrogenation/naphthalene Hydrogenation pair as a Hydrogen Source for fuel-cell vehicle
International Journal of Hydrogen Energy, 2003Co-Authors: Shinya Hodoshima, Shigeki Takaiwa, Hiroshi Arai, Yasukazu SaitoAbstract:Abstract A catalytic decalin deHydrogenation/naphthalene Hydrogenation pair has been proposed as a Hydrogen Source for fuel-cell vehicles in the present study. In order to evolve Hydrogen from decalin efficiently under mild conditions, its catalytic deHydrogenation in a liquid-film type reactor was adopted with use of carbon-supported platinum-based fine particles under reactive distillation conditions. The catalyst layer was superheated in the liquid-film state, which gave much higher Hydrogen evolution rates and conversions at 210°C than those in the suspended state. Requirements concerning high-evolution rates of Hydrogen or high-power densities for practical fuel-cell vehicle operations would be fulfilled enough at around 280°C. As for the storage densities of Hydrogen on both weight and volume bases (7.3 wt %, 64.8 kg-H 2 / m 3 ) , it is to be noted that their magnitudes are higher than the storage densities (6.5 wt %, 62.0 kg-H 2 / m 3 ) targeted by the Department of Energy, USA (DOE).
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catalytic decalin deHydrogenation naphthalene Hydrogenation pair as a Hydrogen Source for fuel cell vehicle
International Journal of Hydrogen Energy, 2003Co-Authors: Shinya Hodoshima, Shigeki Takaiwa, Hiroshi Arai, Yasukazu SaitoAbstract:Abstract A catalytic decalin deHydrogenation/naphthalene Hydrogenation pair has been proposed as a Hydrogen Source for fuel-cell vehicles in the present study. In order to evolve Hydrogen from decalin efficiently under mild conditions, its catalytic deHydrogenation in a liquid-film type reactor was adopted with use of carbon-supported platinum-based fine particles under reactive distillation conditions. The catalyst layer was superheated in the liquid-film state, which gave much higher Hydrogen evolution rates and conversions at 210°C than those in the suspended state. Requirements concerning high-evolution rates of Hydrogen or high-power densities for practical fuel-cell vehicle operations would be fulfilled enough at around 280°C. As for the storage densities of Hydrogen on both weight and volume bases (7.3 wt %, 64.8 kg-H 2 / m 3 ) , it is to be noted that their magnitudes are higher than the storage densities (6.5 wt %, 62.0 kg-H 2 / m 3 ) targeted by the Department of Energy, USA (DOE).
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Catalytic decalin deHydrogenation/naphthalene Hydrogenation pair as a Hydrogen Source for fuel-cell vehicle
International Journal of Hydrogen Energy, 2003Co-Authors: Shinya Hodoshima, Shigeki Takaiwa, Hiroshi Arai, Yasukazu SaitoAbstract:A catalytic decalin deHydrogenation/naphthalene Hydrogenation pair has been proposed as a Hydrogen Source for fuel-cell vehicles in the present study. In order to evolve Hydrogen from decalin efficiently under mild conditions, its catalytic deHydrogenation in a liquid-film type reactor was adopted with use of carbon-supported platinum-based fine particles under reactive distillation conditions. The catalyst layer was superheated in the liquid-film state, which gave much higher Hydrogen evolution rates and conversions at 210°C than those in the suspended state. Requirements concerning high-evolution rates of Hydrogen or high-power densities for practical fuel-cell vehicle operations would be fulfilled enough at around 280°C. As for the storage densities of Hydrogen on both weight and volume bases (7.3 wt%,64.8 kg-H2/m3), it is to be noted that their magnitudes are higher than the storage densities (6.5 wt%,62.0 kg-H2/m3) targeted by the Department of Energy, USA (DOE). © 2003 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
Sejin Kwon - One of the best experts on this subject based on the ideXlab platform.
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The proton exchange membrane fuel cell systems using methanolysis of sodium borohydride as a Hydrogen Source with cobalt catalysts
International Journal of Green Energy, 2016Co-Authors: Byeong Gyu Gang, Sejin KwonAbstract:ABSTRACTConstant Hydrogen generation via a Hydrogen generator is evaluated from the methanolysis of sodium borohydride (NaBH4) using Co/Al2O3 and MnOx/Al2O3 catalysts. Chemical borohydrides coupled with catalysts can be used for compact storage and to create efficient generation systems. Thus, we first report the catalytic activity of MnOx/Al2O3, which is synthesized using the simple wet-impregnation method, for the methanolysis reaction. The results indicate that both catalysts can effectively accelerate the methanolysis reaction and provide constant Hydrogen generation rates. Thus, we integrate this Hydrogen generation system into a proton exchange membrane fuel cell stack (PEMFC) to determine whether it can be used as a portable power supply. As a result, this fuel cell system operates at 40 W for 1 hr using the Hydrogen Source supplied from the catalytic methanolysis reaction.
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fuel cell system with sodium borohydride as Hydrogen Source for unmanned aerial vehicles
Journal of Power Sources, 2011Co-Authors: Sejin KwonAbstract:Abstract In this study, we design and fabricate a fuel cell system for application as a power Source in unmanned aerial vehicles (UAVs). The fuel cell system consists of a fuel cell stack, Hydrogen generator, and hybrid power management system. PEMFC stack with an output power of 100 W is prepared and tested to decide the efficient operating conditions; the stack must be operated in the dead-end mode with purge in order to ensure prolonged stack performance. A Hydrogen generator is fabricated to supply gaseous Hydrogen to the stack. Sodium borohydride (NaBH 4 ) is used as the Hydrogen Source in the present study. Co/Al 2 O 3 catalyst is prepared for the hydrolysis of the alkaline NaBH 4 solution at room temperature. The fabricated Co catalyst is comparable to the Ru catalyst. The UAV consumes more power in the takeoff mode than in the cruising mode. A hybrid power management system using an auxiliary battery is developed and evaluated for efficient energy management. Hybrid power from both the fuel cell and battery powers takeoff and turning flight operations, while the fuel cell supplies steady power during the cruising flight. The capabilities of the fuel-cell UAVs for long endurance flights are validated by successful flight tests.
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Fuel cell system with sodium borohydride as Hydrogen Source for unmanned aerial vehicles
Journal of Power Sources, 2011Co-Authors: Kyunghwan Kim, Kiseong Lee, Taegyu Kim, Sejin KwonAbstract:In this study, we design and fabricate a fuel cell system for application as a power Source in unmanned aerial vehicles (UAVs). The fuel cell system consists of a fuel cell stack, Hydrogen generator, and hybrid power management system. PEMFC stack with an output power of 100 W is prepared and tested to decide the efficient operating conditions; the stack must be operated in the dead-end mode with purge in order to ensure prolonged stack performance. A Hydrogen generator is fabricated to supply gaseous Hydrogen to the stack. Sodium borohydride (NaBH4) is used as the Hydrogen Source in the present study. Co/Al2O3 catalyst is prepared for the hydrolysis of the alkaline NaBH4 solution at room temperature. The fabricated Co catalyst is comparable to the Ru catalyst. The UAV consumes more power in the takeoff mode than in the cruising mode. A hybrid power management system using an auxiliary battery is developed and evaluated for efficient energy management. Hybrid power from both the fuel cell and battery powers takeoff and turning flight operations, while the fuel cell supplies steady power during the cruising flight. The capabilities of the fuel-cell UAVs for long endurance flights are validated by successful flight tests. © 2011 Elsevier B.V.
Kohki Ebitani - One of the best experts on this subject based on the ideXlab platform.
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base free chemoselective transfer Hydrogenation of nitroarenes to anilines with formic acid as Hydrogen Source by a reusable heterogeneous pd zrp catalyst
RSC Advances, 2014Co-Authors: Jaya Tuteja, Shun Nishimura, Kohki EbitaniAbstract:A highly efficient, chemoselective, environmentally-benign method is developed for the catalytic transfer Hydrogenation (CTH) of nitroarenes using FA as a Hydrogen Source. Various supported Pd catalysts were examined for this transformation, and Pd supported ZrP (Pd/ZrP) proved to be the best catalyst for CTH of nitrobenzene. Applicability of the Pd/ZrP catalyst is also explored for Hydrogenation of various substituted nitroarenes. The Pd/ZrP catalyst showed high specificity for Hydrogenation of nitro groups even in the presence of other reducible functional groups such as –CC, –COOCH3, and –CN. To investigate the reaction mechanism, a Hammett plot was obtained for CTH of p-substituted nitroarenes. The active site is thought to be in situ generated Pd(0) species as seen from XRD and TEM data. The Pd/ZrP catalyst is reusable at least up to 4 times while maintaining the same activity and selectivity. To the best of our knowledge, this is one of the best methodologies for CTH of nitroarenes under base-free conditions with high activity and chemoselectivity over heterogeneous Pd-based catalysts.
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production of γ valerolactone from biomass derived compounds using formic acid as a Hydrogen Source over supported metal catalysts in water solvent
RSC Advances, 2014Co-Authors: Shun Nishimura, Kohki EbitaniAbstract:γ-Valerolactone (GVL) is a key intermediate for production of fuels and chemicals. In this research, GVL is synthesized from biomass-derived compounds using formic acid (FA) as a Hydrogen Source over various supported metal catalysts which are prepared by a simple impregnation or co-precipitation method. Under optimum conditions, levulinic acid (LA) is almost converted to GVL by Ru/C, Ru/SBA, Au/ZrC and Au/ZrO2 catalysts with above 90% yield in water solvent. Especially, the Au/ZrO2 showed excellent activity and recyclability; the Au/ZrO2 catalyst can decompose completely FA to CO2 and H2, which gives high yield of GVL (ca. 97%) from Hydrogenation of LA, and can retain its activity for at least 5 recycle runs. GVL is also obtained from one-pot dehydration/Hydrogenation reaction of fructose in water solvent. In this reaction, FA plays two roles: an acid catalyst for dehydration of fructose to LA, and a Hydrogen Source for Hydrogenation of the obtained LA over supported metal catalysts. The Au/ZrO2 is the best catalyst for dehydration/Hydrogenation reaction with overall GVL yield of 48% and can be reused several times.
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Direct Synthesis of 1,6‐Hexanediol from HMF over a Heterogeneous Pd/ZrP Catalyst using Formic Acid as Hydrogen Source
Chemsuschem, 2013Co-Authors: Jaya Tuteja, Hemant Choudhary, Shun Nishimura, Kohki EbitaniAbstract:A new approach is developed for Hydrogenolytic ring opening of biobased 5-hydroxymethylfurfural (HMF), dehydration product of hexoses, towards 1,6-hexanediol (HDO) under atmospheric pressure. The highest yield of HDO, 43%, is achieved over reusable Pd/zirconium phosphate (ZrP) catalyst at 413 K in the presence of formic acid as Hydrogen Source. In comparison with various Brønsted and/or Lewis acidic supports, the specific Brønsted acidity on ZrP support effectively accelerated the cleavage of C-O bond in a furan ring.
Eli Ruckenstein - One of the best experts on this subject based on the ideXlab platform.
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Hydrogen Storage in LiNH2/Li3N Material for H2/CO2 Mixture Gas as Hydrogen Source
Industrial & Engineering Chemistry Research, 2008Co-Authors: Yun Hang Hu, Eli RuckensteinAbstract:Our previous work showed that the preaddition of LiNH2 into Li3N increases the reversible Hydrogen capacity up to about 6.8 wt % H2. Herein, we report that the H2/CO2 gas mixture can be directly used as Hydrogen Source for Hydrogen storage in LiNH2/Li3N. Furthermore, it was found that 20% CO2 in H2 did not affect the high Hydrogen capacity and the fast adsorption kinetics of LiNH2/Li3N. This material provides an opportunity to eliminate a preseparation step before Hydrogen storage, which can greatly reduce the Hydrogen storage cost.
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Hydrogen storage in linh2 li3n material for h2 co2 mixture gas as Hydrogen Source
Industrial & Engineering Chemistry Research, 2008Co-Authors: Yun Hang Hu, Eli RuckensteinAbstract:Our previous work showed that the preaddition of LiNH2 into Li3N increases the reversible Hydrogen capacity up to about 6.8 wt % H2. Herein, we report that the H2/CO2 gas mixture can be directly used as Hydrogen Source for Hydrogen storage in LiNH2/Li3N. Furthermore, it was found that 20% CO2 in H2 did not affect the high Hydrogen capacity and the fast adsorption kinetics of LiNH2/Li3N. This material provides an opportunity to eliminate a preseparation step before Hydrogen storage, which can greatly reduce the Hydrogen storage cost.
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Steam-Reforming Product (H2/CO2 Mixture) Used as a Hydrogen Source for Hydrogen Storage in Li3N
Industrial & Engineering Chemistry Research, 2007Co-Authors: Yun Hang Hu, Eli RuckensteinAbstract:Hydrogen purification and storage are critical issues in the transportation application of Hydrogen fuel. Herein, we report that Hydrogen can be separated from other components during its storage in Li3N, when the steam-reforming product of natural gas is employed as the Hydrogen Source. The kinetics and capacity of Hydrogen absorption of Li3N are not affected by CO2, and only the kinetics is slightly affected by CO. During desorption, the Hydrogen stored in Li3N can be released, thus providing a pure Hydrogen Source for fuel cells or other applications. The simultaneous separation of Hydrogen during its storage tremendously reduces the cost of the Hydrogen fuel for transportation and also provides a novel process for Hydrogen purification.
Lijin Xu - One of the best experts on this subject based on the ideXlab platform.
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iridium catalyzed transfer Hydrogenation of 1 10 phenanthrolines using formic acid as the Hydrogen Source
Advanced Synthesis & Catalysis, 2016Co-Authors: Conghui Xu, Lingjuan Zhang, Chaonan Dong, Jianbin Xu, Yali Li, Hanyu Zhang, Huanrong Li, Zhiyong Yu, Lijin XuAbstract:The iridium-catalyzed highly regioselective transfer Hydrogenation of a variety of 2-substituted and 2,9-disubstituted 1,10-phenanthrolines under mild conditions with formic acid as the Hydrogen Source is described. In the presence of a catalytic amount of the iridium complex [Cp*IrCl2]2, the transfer Hydrogenation proceeded smoothly in 1,4-dioxane under ligand-free conditions, exclusively leading to a range of 1,2,3,4-tetrahydro-1,10-phenanthroline products in high yields. The catalyst generated in situ from [Cp*IrCl2]2 and (R,R)-(CF3)2C6H3SO2-dpen [N-(2-amino-1,2-diphenylethyl)-3,5-bis(trifluoromethyl)benzenesulfonamide] could efficiently catalyze the asymmetric transfer Hydrogenation of these 1,10-phenanthrolines in isopropyl alcohol (i-PrOH) to afford chiral 1,2,3,4-tetrahydro-1,10-phenanthrolines in high yields with up to >99% ee. The key to the success of the reduction is the choice of solvent and Hydrogen Source.
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Iridium‐Catalyzed Transfer Hydrogenation of 1,10‐Phenanthrolines using Formic Acid as the Hydrogen Source
Advanced Synthesis & Catalysis, 2016Co-Authors: Conghui Xu, Lingjuan Zhang, Chaonan Dong, Jianbin Xu, Yali Li, Hanyu Zhang, Huanrong Li, Zhiyong Yu, Lijin XuAbstract:The iridium-catalyzed highly regioselective transfer Hydrogenation of a variety of 2-substituted and 2,9-disubstituted 1,10-phenanthrolines under mild conditions with formic acid as the Hydrogen Source is described. In the presence of a catalytic amount of the iridium complex [Cp*IrCl2]2, the transfer Hydrogenation proceeded smoothly in 1,4-dioxane under ligand-free conditions, exclusively leading to a range of 1,2,3,4-tetrahydro-1,10-phenanthroline products in high yields. The catalyst generated in situ from [Cp*IrCl2]2 and (R,R)-(CF3)2C6H3SO2-dpen [N-(2-amino-1,2-diphenylethyl)-3,5-bis(trifluoromethyl)benzenesulfonamide] could efficiently catalyze the asymmetric transfer Hydrogenation of these 1,10-phenanthrolines in isopropyl alcohol (i-PrOH) to afford chiral 1,2,3,4-tetrahydro-1,10-phenanthrolines in high yields with up to >99% ee. The key to the success of the reduction is the choice of solvent and Hydrogen Source.
