The Experts below are selected from a list of 11298 Experts worldwide ranked by ideXlab platform
Philippe Miele - One of the best experts on this subject based on the ideXlab platform.
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lithium hydrazinidoborane a polymorphic Material with potential for chemical Hydrogen Storage
ChemInform, 2014Co-Authors: Romain Moury, Takayuki Ichikawa, Umit B Demirci, Voraksmy Ban, Yaroslav Filinchuk, Liang Zeng, Kiyotaka Goshome, Philippe MieleAbstract:Polymorphic LiN2H4BH3 (LiHB) Hydrogen Storage Material is prepared mechanochemically from equimolar amounts of N2H4BH3 and LiH (ball milling, 200 rpm, 18 x 10 min).
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a simple preparation method of sodium amidoborane highly efficient derivative of ammonia borane deHydrogenating at low temperature
International Journal of Hydrogen Energy, 2011Co-Authors: Fabien Sandra, Umit B Demirci, Romain Moury, Rodica Chiriac, Philippe MieleAbstract:Abstract The present work reports the straightforward preparation of sodium amidoborane NaNH2BH3, an ammonia borane derivative (NH3BH3). NaNH2BH3 is a promising solid-state Hydrogen Storage Material, known to deHydrogenate in milder conditions than its parent compound. The preparation was made from sodium hydride NaH and NH3BH3 according to three different energy-efficient routes: namely, ball-milling, grinding in a mortar, and simple mixing with a spatula. In each case, NaNH2BH3 was formed. In other words, it has been demonstrated that the solid–solid reaction between NaH and NH3BH3 can take place by simple contact of these molecules, owing to the basic character of the former and the acidity of the latter. The as-formed Materials deHydrogenate to a high extent at low temperature, with ca. 2 equivalent Hydrogen H2 (NH3-free in our conditions) evolving at temperatures up to 95 °C. An effective gravimetric Hydrogen density of ca. 7.4 wt% was calculated, which may correspond to an effective capacity of 3.7 wt% (assuming the weight of NaNH2BH3 amounts to 50% of the weight of the whole Storage system). Such performance confirms the high potential of amidoboranes as Hydrogen Storage Material, especially when compared to NH3BH3.
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chemical Hydrogen Storage Material gravimetric capacity versus system gravimetric capacity
Energy and Environmental Science, 2011Co-Authors: Umit B Demirci, Philippe MieleAbstract:Chemical Hydrogen Storage Materials (CHSMs), owing to their high Hydrogen content, are presented as having high potential to achieve high gravimetric Hydrogen Storage capacities in the prospect of technological applications (e.g. vehicle). However, this raises two questions. Is the Storage capacity viewed at the Material level or at the system level? Do we talk about absolute, excess or net capacities? Being exact in the terms used is all important so the US Department of Energy has set well-defined, precise technical requirements for vehicle application at the system level. This Minireview focuses on the terms that have been used in the open literature to present the Storage capacities of the CHSMs. It stands out, through several typical cases, that the terms are generally misused and mislead the reader on the real capacities. For instance, the Material level and the system level are often lumped together. Herein, we re-define the much-used terms and expressions, and propose a set of expressions to systematically use in order to avoid any future misuse, misleading terms and misunderstanding.
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sodium borohydride versus ammonia borane in Hydrogen Storage and direct fuel cell applications
Energy and Environmental Science, 2009Co-Authors: Umit B Demirci, Philippe MieleAbstract:Since the late 1990s, sodium borohydride (NaBH4, denoted SB) is presented as a promising Hydrogen Storage Material and an attractive fuel (aqueous solution) of the direct fuel cell (or direct liquid-feed fuel cell). In 2007, the U.S. Department of Energy recommended a no-go for SB for vehicular applications and suggested work on ammonia borane (AB), another promising Hydrogen Storage Material, which is also considered as a fuel for the direct fuel cell. Both boron hydrides in Hydrogen and fuel cell applications are the topics of the present paper. The basics, issues, solutions to the issues and state-of-the-art are tackled but the discussion aims to compare the hydrides for either application. It is shown that there are many similarities between SB and AB in their features and applications. Nevertheless SB and AB as Hydrogen Storage Materials do not compete. Rather, SB is intended more to portable technologies while AB to vehicular applications. Otherwise, when these hydrides are utilised as fuels of direct fuel cell, one question arises: what can be the advantage of developing the AB-powered fuel cell when it seems to be less effective, practical, and more complex than the SB-powered fuel cell? These aspects are discussed. However that may be, it is concluded that both SB and AB are not mature enough for the applications considered.
Umit B Demirci - One of the best experts on this subject based on the ideXlab platform.
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lithium hydrazinidoborane a polymorphic Material with potential for chemical Hydrogen Storage
ChemInform, 2014Co-Authors: Romain Moury, Takayuki Ichikawa, Umit B Demirci, Voraksmy Ban, Yaroslav Filinchuk, Liang Zeng, Kiyotaka Goshome, Philippe MieleAbstract:Polymorphic LiN2H4BH3 (LiHB) Hydrogen Storage Material is prepared mechanochemically from equimolar amounts of N2H4BH3 and LiH (ball milling, 200 rpm, 18 x 10 min).
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a simple preparation method of sodium amidoborane highly efficient derivative of ammonia borane deHydrogenating at low temperature
International Journal of Hydrogen Energy, 2011Co-Authors: Fabien Sandra, Umit B Demirci, Romain Moury, Rodica Chiriac, Philippe MieleAbstract:Abstract The present work reports the straightforward preparation of sodium amidoborane NaNH2BH3, an ammonia borane derivative (NH3BH3). NaNH2BH3 is a promising solid-state Hydrogen Storage Material, known to deHydrogenate in milder conditions than its parent compound. The preparation was made from sodium hydride NaH and NH3BH3 according to three different energy-efficient routes: namely, ball-milling, grinding in a mortar, and simple mixing with a spatula. In each case, NaNH2BH3 was formed. In other words, it has been demonstrated that the solid–solid reaction between NaH and NH3BH3 can take place by simple contact of these molecules, owing to the basic character of the former and the acidity of the latter. The as-formed Materials deHydrogenate to a high extent at low temperature, with ca. 2 equivalent Hydrogen H2 (NH3-free in our conditions) evolving at temperatures up to 95 °C. An effective gravimetric Hydrogen density of ca. 7.4 wt% was calculated, which may correspond to an effective capacity of 3.7 wt% (assuming the weight of NaNH2BH3 amounts to 50% of the weight of the whole Storage system). Such performance confirms the high potential of amidoboranes as Hydrogen Storage Material, especially when compared to NH3BH3.
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chemical Hydrogen Storage Material gravimetric capacity versus system gravimetric capacity
Energy and Environmental Science, 2011Co-Authors: Umit B Demirci, Philippe MieleAbstract:Chemical Hydrogen Storage Materials (CHSMs), owing to their high Hydrogen content, are presented as having high potential to achieve high gravimetric Hydrogen Storage capacities in the prospect of technological applications (e.g. vehicle). However, this raises two questions. Is the Storage capacity viewed at the Material level or at the system level? Do we talk about absolute, excess or net capacities? Being exact in the terms used is all important so the US Department of Energy has set well-defined, precise technical requirements for vehicle application at the system level. This Minireview focuses on the terms that have been used in the open literature to present the Storage capacities of the CHSMs. It stands out, through several typical cases, that the terms are generally misused and mislead the reader on the real capacities. For instance, the Material level and the system level are often lumped together. Herein, we re-define the much-used terms and expressions, and propose a set of expressions to systematically use in order to avoid any future misuse, misleading terms and misunderstanding.
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sodium borohydride versus ammonia borane in Hydrogen Storage and direct fuel cell applications
Energy and Environmental Science, 2009Co-Authors: Umit B Demirci, Philippe MieleAbstract:Since the late 1990s, sodium borohydride (NaBH4, denoted SB) is presented as a promising Hydrogen Storage Material and an attractive fuel (aqueous solution) of the direct fuel cell (or direct liquid-feed fuel cell). In 2007, the U.S. Department of Energy recommended a no-go for SB for vehicular applications and suggested work on ammonia borane (AB), another promising Hydrogen Storage Material, which is also considered as a fuel for the direct fuel cell. Both boron hydrides in Hydrogen and fuel cell applications are the topics of the present paper. The basics, issues, solutions to the issues and state-of-the-art are tackled but the discussion aims to compare the hydrides for either application. It is shown that there are many similarities between SB and AB in their features and applications. Nevertheless SB and AB as Hydrogen Storage Materials do not compete. Rather, SB is intended more to portable technologies while AB to vehicular applications. Otherwise, when these hydrides are utilised as fuels of direct fuel cell, one question arises: what can be the advantage of developing the AB-powered fuel cell when it seems to be less effective, practical, and more complex than the SB-powered fuel cell? These aspects are discussed. However that may be, it is concluded that both SB and AB are not mature enough for the applications considered.
Xiangdong Yao - One of the best experts on this subject based on the ideXlab platform.
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progress in sodium borohydride as a Hydrogen Storage Material development of hydrolysis catalysts and reaction systems
International Journal of Hydrogen Energy, 2011Co-Authors: Sean S Muir, Xiangdong YaoAbstract:Abstract Over the past decade, sodium borohydride (NaBH4) has been extensively investigated as a potential Hydrogen Storage Material. The development of catalyst Materials for on demand NaBH4 hydrolysis, and the design of practical reaction systems for Hydrogen Storage based on NaBH4 are key research areas. Progress in the former area has been promising, with many non-noble catalysts being reported with activities comparable to those of higher-cost noble metal catalysts. However, the design of practical Hydrogen Storage systems remains a critical issue, as identified by the U.S. Department of Energy (DOE) in their “No-Go” recommendation in 2007. The problems of by-product precipitation and catalyst blockage at high NaBH4 concentrations must be addressed in order to produce a Hydrogen Storage system capable of meeting the DOE target of 5.5 wt% H2 (2015). It is likely that a new, novel reaction system design will be required to achieve these targets, given the limitations identified in conventional systems. Moreover, a new process for regenerating spent NaBH4 will need to be developed, in order to lower its cost to a viable level for use as a transportation fuel.
Tom Autrey - One of the best experts on this subject based on the ideXlab platform.
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bis bn cyclohexane a remarkably kinetically stable chemical Hydrogen Storage Material
Journal of the American Chemical Society, 2015Co-Authors: Gang Chen, Lev N. Zakharov, Abhijeet J. Karkamkar, Mark E Bowden, Sean M Whittemore, Edward B Garner, Tanya Mikulas, David A Dixon, Tom AutreyAbstract:A critical component for the successful development of fuel cell applications is Hydrogen Storage. For back-up power applications, where long Storage periods under extreme temperatures are expected, the thermal stability of the Storage Material is particularly important. Here, we describe the development of an unusually kinetically stable chemical Hydrogen Storage Material with a H2 Storage capacity of 4.7 wt%. The compound, which is the first reported parental BN isostere of cyclohexane featuring two BN units, is thermally stable up to 150 °C both in solution and as a neat Material. Yet, it can be activated to rapidly desorb H2 at room temperature in the presence of a catalyst without releasing other detectable volatile contaminants. We also disclose the isolation and characterization of two cage compounds with S4 symmetry from the H2 desorption reactions.
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Synthesis of ammonia borane for Hydrogen Storage applications
Energy and Environmental Science, 2008Co-Authors: David J Heldebrant, Abhijeet J. Karkamkar, John C. Linehan, Tom AutreyAbstract:A new synthetic procedure to make the condensed phase Hydrogen Storage Material, ammonia borane (NH3BH3, abbreviated as AB), is described and compared with previous literature procedures. Ammonia borane with a gravimetric density ca. 194 gm H2 kg−1 and a volumetric density ca. 146 H2 litre−1, is a promising chemical Hydrogen Storage Material for fuel cell powered applications. The work shows that ammonium borohydride, NH4BH4, formed in situ by the metathesis of NH4X and MBH4 salts (M = Na, Li; X = Cl, F) in liquid NH3, can be induced to decompose in an organic ether to yield AB in near quantitative yield. The purity of the AB prepared by this one-pot synthetic strategy is sufficient to meet the thermal stability requirements for on-board Hydrogen Storage.
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the thermal decomposition of ammonia borane a potential Hydrogen Storage Material
Current Applied Physics, 2008Co-Authors: Mark E Bowden, Tom Autrey, I W M Brown, Martin RyanAbstract:Abstract One equivalent of Hydrogen gas is evolved from ammonia borane (NH 3 BH 3 ) when it is heated above 70 °C. The initial stages of this process have been examined using TG/DSC, optical microscopy, and high temperature X-ray diffraction. Two exothermic events have been observed, the first of which takes place without Hydrogen evolution. During this stage, the sample loses its crystallinity and birefringence. The products are believed to be a more mobile form of NH 3 BH 3 and the diammoniate of diborane ([NH 3 BH 2 NH 3 ] + [BH 4 ] − ). These products subsequently react in the second exothermic stage to generate Hydrogen.
Sanjay Kumar - One of the best experts on this subject based on the ideXlab platform.
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development of vanadium based Hydrogen Storage Material a review
Renewable & Sustainable Energy Reviews, 2017Co-Authors: Sanjay Kumar, Ankur Jain, Takayuki Ichikawa, Yoshitsugu Kojima, Gautam Kumar DeyAbstract:The metallic vanadium has an excellent Hydrogen Storage properties in comparison to other hydride forming metals such as titanium, uranium, and zirconium. The gravimetric Storage capacity of vanadium is over 4wt% which is even better than AB2 and AB5 alloys. The metallic vanadium has shown high Hydrogen solubility and diffusivity at nominal temperature and pressure conditions. Consequently, vanadium is under consideration for the cost-effective Hydrogen permeation membrane to replace palladium. The issues with vanadium are poor reversibility and pulverization. The poor reversibility is because of high thermal stability of β (VH/V2H) phase which eventually restricts the cyclic Hydrogen Storage capacity up to 2wt% at room temperature. The pulverization is because of large crystal misfit between the metal and metal hydride phase. The Hydrogen solubility, phase stability, Hydrogenation-deHydrogenation kinetics, and pulverization are highly influenced by the presence of an alloying element. Therefore, worldwide efforts are to explore and optimize the alloying element which could enhance the Hydrogen solubility, destabilized the β phase, improved the Hydrogenation-deHydrogenation kinetics, and prevent the pulverization. The current review is a systematic presentation of these efforts to resolve the issues of vanadium as a base Material for Hydrogen Storage and permeation membrane.
