Showing papers on "Hydrogen storage published in 2009"
TL;DR: This critical review of the current status of hydrogen storage within microporous metal-organic frameworks provides an overview of the relationships between structural features and the enthalpy of hydrogen adsorption, spectroscopic methods for probing framework-H(2) interactions, and strategies for improving storage capacity.
Abstract: New materials capable of storing hydrogen at high gravimetric and volumetric densities are required if hydrogen is to be widely employed as a clean alternative to hydrocarbon fuels in cars and other mobile applications. With exceptionally high surface areas and chemically-tunable structures, microporous metal–organic frameworks have recently emerged as some of the most promising candidate materials. In this critical review we provide an overview of the current status of hydrogen storage within such compounds. Particular emphasis is given to the relationships between structural features and the enthalpy of hydrogen adsorption, spectroscopic methods for probing framework–H2 interactions, and strategies for improving storage capacity (188 references).
4,511 citations
TL;DR: A review of technologies related to hydrogen production from both fossil and renewable biomass resources including reforming (steam, partial oxidation, autothermal, plasma, and aqueous phase) and pyrolysis is presented in this article.
2,673 citations
TL;DR: Different methods for hydrogen storage are discussed, including high-pressure and cryogenic-liquid storage, adsorptive storage on high-surface-area adsorbents, chemical storage in metal hydride and complex hydrides, and storage in boranes.
Abstract: Hydrogen is a promising energy carrier in future energy systems. However, storage of hydrogen is a substantial challenge, especially for applications in vehicles with fuel cells that use proton-exchange membranes (PEMs). Different methods for hydrogen storage are discussed, including high-pressure and cryogenic-liquid storage, adsorptive storage on high-surface-area adsorbents, chemical storage in metal hydrides and complex hydrides, and storage in boranes. For the latter chemical solutions, reversible options and hydrolytic release of hydrogen with off-board regeneration are both possible. Reforming of liquid hydrogen-containing compounds is also a possible means of hydrogen generation. The advantages and disadvantages of the different systems are compared.
1,222 citations
TL;DR: This critical review briefly covers the various methods of hydrogen storage, and then concentrates on chemical hydrogen storage using B-N compounds.
Abstract: Hydrogen storage for transportation applications requires high volumetric and gravimetric storage capacity. B-N compounds are well suited as storage materials due to their light weight and propensity for bearing multiple protic (N-H) and hydridic (B-H) hydrogens. This critical review briefly covers the various methods of hydrogen storage, and then concentrates on chemical hydrogen storage using B-N compounds. The simplest B-N compound, ammonia borane (H3NBH3), which has a potential 19.6 wt% hydrogen storage capacity, will be emphasised (127 references).
958 citations
TL;DR: This tutorial review provides an overview of the different types of metal hydride and complex hydrides being investigated for on-board and off-board hydrogen storage along with a few new approaches to improving the hydrogenation-dehydrogenation properties.
Abstract: The emergence of a Hydrogen Economy will require the development of new media capable of safely storing hydrogen in a compact and light weight package. Metal hydrides and complex hydrides, where hydrogen is chemically bonded to the metal atoms in the bulk, offer some hope of overcoming the challenges associated with hydrogen storage. The objective is to find a material with a high volumetric and gravimetric hydrogen density that can also meet the unique demands of a low temperature automotive fuel cell. Currently, there is considerable effort to develop new materials with tunable thermodynamic and kinetic properties. This tutorial review provides an overview of the different types of metal hydrides and complex hydrides being investigated for on-board (reversible) and off-board (non-reversible) hydrogen storage along with a few new approaches to improving the hydrogenation–dehydrogenation properties.
783 citations
TL;DR: In this article, the up-and-coming hydrogen energy economy, its environmental and climatic relevance, its exergizing influence on the energy system, its effect on decarbonizing fossil fueled power plants, the introduction of the novel non-heat-engine-related electrochemical energy converter fuel cell in portable electronics, in stationary and mobile applications.
562 citations
TL;DR: This critical review covers the application of computer simulations, including quantum calculations (ab initio and DFT), grand canonical Monte-Carlo simulations, and molecular dynamics simulations, to the burgeoning area of the hydrogen storage by metal- organic frameworks and covalent-organic frameworks.
Abstract: This critical review covers the application of computer simulations, including quantum calculations (ab initio and DFT), grand canonical Monte-Carlo simulations, and molecular dynamics simulations, to the burgeoning area of the hydrogen storage by metal–organic frameworks and covalent-organic frameworks. This review begins with an overview of the theoretical methods obtained from previous studies. Then strategies for the improvement of hydrogen storage in the porous materials are discussed in detail. The strategies include appropriate pore size, impregnation, catenation, open metal sites in metal oxide parts and within organic linker parts, doping of alkali elements onto organic linkers, substitution of metal oxide with lighter metals, functionalized organic linkers, and hydrogen spillover (186 references).
530 citations
TL;DR: The result suggests that the porous carbon with large amounts of active sites, high surface area, and high micropore volume related to optimum pore size could achieve high gravimetric hydrogen storage.
Abstract: A kind of activated carbon with further carbon dioxide and potassium hydroxide activations for hydrogen storage was investigated. The carbon dioxide and potassium hydroxide activations have apparently different effects on the pore structures and textures of the activated carbon which closely associated with the hydrogen storage properties. The potassium hydroxide activation can remarkably donate microporosity to the frameworks of the activated carbon. One of the resultant porous carbons exhibited a high surface area of up to 3190 m2 g−1 and large gravimetric hydrogen uptake capacity of 7.08 wt % at 77 K and 20 bar, which is one of the largest data reported for the porous carbon materials. This result suggests that the porous carbon with large amounts of active sites, high surface area, and high micropore volume related to optimum pore size could achieve high gravimetric hydrogen storage.
475 citations
TL;DR: In this article, a new idea of combining metal hydride and high pressure was proposed to solve some difficulties and improve performance such as gravimetric density, but it has several difficulties for the vehicle applications such as low temperature discharge characteristics and quick charge capability due to its reaction heat.
467 citations
TL;DR: It is found that the enhanced binding of molecular hydrogen in ion-exchanged ZMOFs with an anionic framework is largely governed by the presence of the electrostatic field in the cavity, which is reflected by isosteric heats of adsorption in these compounds which are greater by as much as 50% relative to those in neutral MOFs.
Abstract: Zeolite-like metal−organic frameworks (ZMOFs) are anionic, have readily exchangeable extra-framework cations, and can be constructed with a variety of organic linkers. ZMOFs therefore can be regard...
449 citations
TL;DR: In this paper, the challenges, distinguishing traits, and apparent contradictions of carbon-based hydrogen storage technologies and to emphasize recently developed nanostructured carbon materials that show potential to store hydrogen by physisorption and/or chemistry-based mechanisms.
TL;DR: An anionic MOF material built from In(iii) centres and tetracarboxylic acid ligands (H4L) in which kinetic trapping behaviour—where hydrogen is adsorbed at high pressures but not released immediately on lowering the pressure—is modulated by guest cations.
Abstract: Metal-organic frameworks (MOFs)--microporous materials constructed by bridging metal centres with organic ligands--show promise for applications in hydrogen storage, which is a key challenge in the development of the 'hydrogen economy'. Their adsorption capacities, however, have remained insufficient for practical applications, and thus strategies to enhance hydrogen-MOF interactions are required. Here we describe an anionic MOF material built from In(III) centres and tetracarboxylic acid ligands (H(4)L) in which kinetic trapping behaviour--where hydrogen is adsorbed at high pressures but not released immediately on lowering the pressure--is modulated by guest cations. With piperazinium dications in its pores, the framework exhibits hysteretic hydrogen adsorption. On exchange of these dications with lithium cations, no hysteresis is seen, but instead there is an enhanced adsorption capacity coupled to an increase in the isosteric heat of adsorption. This is rationalized by the different locations of the cations within the pores, determined with precision by X-ray crystallography.
TL;DR: Progress towards hydrogen storage with nanoporous materials in general and porous organic polymers in particular is critically reviewed and strategies for controlling hydrogen storage capacity and adsorption enthalpy via manipulation of surface area, pore size, and pore volume are discussed in detail.
Abstract: The design of hydrogen storage materials is one of the principal challenges that must be met before the development of a hydrogen economy. While hydrogen has a large specific energy, its volumetric energy density is so low as to require development of materials that can store and release it when needed. While much of the research on hydrogen storage focuses on metal hydrides, these materials are currently limited by slow kinetics and energy inefficiency. Nanostructured materials with high surface areas are actively being developed as another option. These materials avoid some of the kinetic and thermodynamic drawbacks of metal hydrides and other reactive methods of storing hydrogen. In this work, progress towards hydrogen storage with nanoporous materials in general and porous organic polymers in particular is critically reviewed. Mechanisms of formation for crosslinked polymers, hypercrosslinked polymers, polymers of intrinsic microporosity, and covalent organic frameworks are discussed. Strategies for controlling hydrogen storage capacity and adsorption enthalpy via manipulation of surface area, pore size, and pore volume are discussed in detail.
TL;DR: This work proposes combining the graphene oxide (GO) technique with Ti anchoring to overcome the current synthesis bottleneck for practical storage materials and suggests that GO is primarily made of low-energy oxygen-containing structural motifs on the graphene sheet.
Abstract: Organometallic nanomaterials hold the promise for molecular hydrogen (H(2)) storage by providing nearly ideal binding strength to H(2) for room-temperature applications Synthesizing such materials, however, faces severe setbacks due to the problem of metal clustering Inspired by a recent experimental breakthrough ( J Am Chem Soc 2008 , 130 , 6992 ), which demonstrates enhanced H(2) binding in Ti-grafted mesoporous silica, we propose combining the graphene oxide (GO) technique with Ti anchoring to overcome the current synthesis bottleneck for practical storage materials Similar to silica, GO contains ample hydroxyl groups, which are the active sites for anchoring Ti atoms GO can be routinely synthesized and is much lighter than silica Hence, higher gravimetric storage capacity can be readily achieved Our first-principles computations suggest that GO is primarily made of low-energy oxygen-containing structural motifs on the graphene sheet The Ti atoms bind strongly to the oxygen sites with binding energies as high as 450 kJ/mol This is comparable to that of silica and is indeed enough to prevent the Ti atoms from clustering Each Ti can bind multiple H(2) with the desired binding energies (14-41 kJ/mol-H(2)) The estimated theoretical gravimetric and volumetric densities are 49 wt % and 64 g/L, respectively
TL;DR: In this article, the authors compared the performance of boron hydrides in hydrogen and fuel cell applications and concluded that there are many similarities between SB and AB in their features and applications.
Abstract: 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.
TL;DR: An overview of the boron and nitrogen-based compounds as hydrogen storage materials can be found in this article, where the authors present an overview of their use in PEM fuel cells.
TL;DR: In this article, a hybrid composite of acid-treated multiwalled carbon nanotubes (MWCNTs) and MOF-5 [Zn4O(bdc)3; bdc = 1,4-benzenedicarbocylate] (denoted MOFMC) was synthesized, where well-dispersed MWCNTs were mixed with a DMF solution of zinc nitrate tetrahydrate and terephthalic acid.
Abstract: Metal−organic frameworks (MOFs) are a rapidly growing class of microporous materials. Various MOFs with tailored nanoporosities have recently been developed as potential storage media for natural gases and hydrogen. However, wider applications have been limited because even atmospheric moisture levels cause MOF instability, and unexpectedly low H2 storage capacity, at 298 K. To overcome these problems, we synthesized a hybrid composite of acid-treated multiwalled carbon nanotubes (MWCNTs) and MOF-5 [Zn4O(bdc)3; bdc = 1,4-benzenedicarbocylate] (denoted MOFMC). In a successful synthesis, well-dispersed MWCNTs in dimethylformamide (DMF) were mixed with a DMF solution of zinc nitrate tetrahydrate and terephthalic acid. The MOFMCs obtained had the same crystal structure and morphology as those of virgin MOF-5, but exhibited a much greater Langmuir specific surface area (increased from 2160 to 3550 m2/g), about a 50% increase in hydrogen storage capacity (from 1.2 to 1.52 wt % at 77 K and 1 bar and from 0.3 to ...
TL;DR: The desolvated polyhedral framework material NOTT-112 showed an excess H2 uptake of 7.07 wt% between 35 and 40 bar at 77 K, and a total H 2 uptake of 10 wt % at 77 bar and 77 K as discussed by the authors.
TL;DR: PdNPs significantly increase H(2) uptake capacities, both at 77 K and 1 bar and at 298 K and high pressures, compared to [Zn(3)(ntb)(2)](n) (black).
Abstract: Quick on the uptake: Palladium nanoparticles were fabricated simply by immersing {[Zn(3)(ntb)(2)(EtOH)(2)]4 EtOH}(n) (1) in an MeCN solution of Pd(NO(3))(2) at room temperature, without any extra reducing agent. 3 wt % PdNPs@[1](0.54+)(NO(3)(-))(0.54) significantly increase H(2) uptake capacities, both at 77 K and 1 bar and at 298 K and high pressures (see picture, red curve) compared to [Zn(3)(ntb)(2)](n) (black). ntb = 4,4',4''-nitrilotrisbenzoate.
TL;DR: The current methods envisaged for increasing adsorption at higher temperatures involve modification of the surface chemistry, in particular, the inclusion of open metal centres to increase hydrogen surface site interactions, and utilisation of the framework flexibility are discussed.
Abstract: Hydrogen adsorption on porous materials is one of the possible methods proposed for hydrogen storage for transport applications. High pressure experimental studies of a wide range of porous materials have obtained maximum hydrogen excess capacities of 6–8 wt% at 77 K for metal–organic frameworks (MOFs) and porous carbon materials. Grand canonical Monte Carlo (GCMC) simulation studies indicate that higher hydrogen capacities are possible for covalent organic frameworks (COFs). Currently, the maximum isosteric enthalpies of adsorption of ∼13 kJ mol−1 at 77 K have been observed experimentally for metal–organic framework materials and this is higher than for COFs, where the maximum predicted from GCMC simulations is ∼8 kJ mol−1. Metal–organic framework materials have structural diversity and scope for modification of surface chemistry to enhance hydrogen surface interactions. The synthesis of MOFs with stronger H2–surface interactions to give similar hydrogen capacities at much higher temperatures than 77 K is required and eventually, materials that have these high capacities at ambient temperatures with rapid adsorption/desorption characteristics are necessary for applications as hydrogen storage materials for transport applications. The current methods envisaged for increasing adsorption at higher temperatures involve modification of the surface chemistry, in particular, the inclusion of open metal centres to increase hydrogen surface site interactions, and utilisation of the framework flexibility are discussed.
TL;DR: Rhodium nanoparticles effectively catalyze the decomposition of hydrous hydrazine to produce hydrogen under ambient reaction conditions and show higher catalytic activity in relation to hexadecyltrimethyl ammonium bromide.
Abstract: Rhodium nanoparticles (NPs) effectively catalyze the decomposition of hydrous hydrazine to produce hydrogen under ambient reaction conditions Rh(0) NPs with a particle size of approximately 5 nm prepared in the presence of hexadecyltrimethyl ammonium bromide show higher catalytic activity
TL;DR: Pressure-composition-temperature (PCT) analysis demonstrated that both the nanosize and the addition of TiH(2) contributed to the significant improvement of the kinetics of dehydrogenation and hydrogenation compared to commercial MgH( 2).
Abstract: Magnesium hydride (MgH2) is an attractive candidate for solid-state hydrogen storage applications. To improve the kinetics and thermodynamic properties of MgH2 during dehydrogenation−rehydrogenation cycles, a nanostructured MgH2−0.1TiH2 material system prepared by ultrahigh-energy−high-pressure mechanical milling was investigated. High-resolution transmission electron microscope (TEM) and scanning TEM analysis showed that the grain size of the milled MgH2−0.1TiH2 powder is approximately 5−10 nm with uniform distributions of TiH2 among MgH2 particles. Pressure−composition-temperature (PCT) analysis demonstrated that both the nanosize and the addition of TiH2 contributed to the significant improvement of the kinetics of dehydrogenation and hydrogenation compared to commercial MgH2. More importantly, PCT cycle analysis demonstrated that the MgH2−0.1TiH2 material system showed excellent cycle stability. The results also showed that the ΔH value for the dehydrogenation of nanostructured MgH2−0.1TiH2 is signifi...
TL;DR: A multiscale theoretical method predicts that the gravimetric adsorption capacities of H(2) in Li-doped covalent organic frameworks based on the building blocks shown can reach nearly 7 % at T=298 K and p=100 bar, suggesting that these Li- doped materials are promising adsorbents for hydrogen storage.
Abstract: Quick on the uptake: A multiscale theoretical method predicts that the gravimetric adsorption capacities of H(2) in Li-doped covalent organic frameworks based on the building blocks shown (Li violet, H white, B pink, C green, O red, Si yellow) can reach nearly 7 % at T=298 K and p=100 bar, suggesting that these Li-doped materials are promising adsorbents for hydrogen storage.
TL;DR: Two new hydrogen storage reactions are predicted that are some of the most attractive among the presently known ones and combine high gravimetric densities with low enthalpies and are thermodynamically reversible at low pressures due to low vibrational entropies of the product phases containing the [B(12)H(12)](2-) anion.
Abstract: Introduction of economically viable hydrogen cars is hindered by the need to store large amounts of hydrogen. Metal borohydrides [LiBH(4), Mg(BH(4))(2), Ca(BH(4))(2)] are attractive candidates for onboard storage because they contain high densities of hydrogen by weight and by volume. Using a set of recently developed theoretical first-principles methods, we predict currently unknown crystal structures and hydrogen storage reactions in the Li-Mg-Ca-B-H system. Hydrogen release from LiBH(4) and Mg(BH(4))(2) is predicted to proceed via intermediate Li(2)B(12)H(12) and MgB(12)H(12) phases, while for Ca borohydride two competing reaction pathways (into CaB(6) and CaH(2), and into CaB(12)H(12) and CaH(2)) are found to have nearly equal free energies. We predict two new hydrogen storage reactions that are some of the most attractive among the presently known ones. They combine high gravimetric densities (8.4 and 7.7 wt % H(2)) with low enthalpies [approximately 25 kJ/(mol H(2))] and are thermodynamically reversible at low pressures due to low vibrational entropies of the product phases containing the [B(12)H(12)](2-) anion.
TL;DR: The first crystalline beryllium-based metal-organic framework has been synthesized and found to exhibit an exceptional surface area useful for hydrogen storage, and it is expected that reaction conditions similar to those reported here may enable the synthesis of a broad new family of berylla-based frameworks with extremely high surface areas.
Abstract: The first crystalline beryllium-based metal-organic framework has been synthesized and found to exhibit an exceptional surface area useful for hydrogen storage. Reaction of 1,3,5-benzenetribenzoic acid (H(3)BTB) and beryllium nitrate in a mixture of DMSO, DMF, and water at 130 degrees C for 10 days affords the solvated form of Be(12)(OH)(12)(1,3,5-benzenetribenzoate)(4) (1). Its highly porous framework structure consists of unprecedented saddle-shaped [Be(12)(OH)(12)](12+) rings connected through tritopic BTB(3-) ligands to generate a 3,12 net. Compound 1 exhibits a BET surface area of 4030 m(2)/g, the highest value yet reported for any main group metal-organic framework or covalent organic framework. At 77 K, the H(2) adsorption data for 1 indicate a fully reversible uptake of 1.6 wt % at 1 bar, with an initial isosteric heat of adsorption of -5.5 kJ/mol. At pressures up to 100 bar, the data show the compound to serve as an exceptional hydrogen storage material, reaching a total uptake of 9.2 wt % and 44 g/L at 77 K and of 2.3 wt % and 11 g/L at 298 K. It is expected that reaction conditions similar to those reported here may enable the synthesis of a broad new family of beryllium-based frameworks with extremely high surface areas.
TL;DR: A synergic effect of Rh and Ni in the bimetallic Rh(4)Ni nanocatalyst makes it possible to achieve a 100% selectivity for hydrogen generation by complete decomposition of hydrous hydrazine at room temperature.
Abstract: A synergic effect of Rh and Ni in the bimetallic Rh4Ni nanocatalyst (Rh/Ni ratio = 4:1) makes it possible to achieve a 100% selectivity for hydrogen generation by complete decomposition of hydrous hydrazine at room temperature. The Rh4Ni nanocatalysts with a particle size of ∼3 nm were prepared by alloying Rh and Ni using a coreduction process in the presence of hexadecyltrimethyl ammonium bromide (CTAB).
TL;DR: The hydrogen storage properties of nanoconfined MgH(2) were studied by Sieverts' measurements and thermal desorption spectroscopy, which clearly demonstrated that the dehydrogenation kinetics of the confined hydride depends on the pore size distribution of the scaffold material.
Abstract: Nanoparticles of magnesium hydride were embedded in nanoporous carbon aerogel scaffold materials in order to explore the kinetic properties of hydrogen uptake and release. A new modified procedure for the synthesis of magnesium hydride nanoparticles is presented. The procedure makes use of monoliths (∼0.4 cm3) of two distinct types of nanoporous resorcinol−formaldehyde carbon aerogels loaded with dibutylmagnesium, MgBu2. Excess MgBu2 was removed mechanically, and the increase in mass was used as a measure of the amount of embedded MgH2. Energy-dispersive spectrometry revealed that MgH2 was uniformly distributed within the aerogel material. In situ synchrotron radiation powder X-ray diffraction showed that MgBu2 transformed directly to MgH2 at T ∼ 137 °C and p(H2) = 50 bar. Two distinct aerogel samples, denoted X1 and X2, with pore volumes of 1.27 and 0.65 mL/g and average pore sizes of 22 and 7 nm, respectively, were selected. In these samples, the uptake of magnesium hydride was found to be proportional ...
TL;DR: The U.S. Department of Energy (US DOE) recommended a no-go for sodium borohydride (NaBH 4 ) for on-board automotive hydrogen storage.
TL;DR: In this article, the pore size and shape of carbide-derived carbons (CDCs) has been investigated for hydrogen storage at high pressure and low temperature and it has been experimentally demonstrated that pores of 0.6-0.7 nm in diameter provide the largest H 2 uptake per unit SSA at elevated pressures and liquid nitrogen temperatures.
TL;DR: In this article, the decomposition of crystalline magnesium borohydride upon heating was studied using thermal desorption, calorimetry, in situ X-ray diffraction, and solid state NMR.