Showing papers on "Hydrogen storage published in 2012"
3,087 citations
TL;DR: In this article, the textural properties and surface chemistry of KOH-activated carbons depend on not only the synthesis parameters, but also different carbon sources employed including fossil/biomass-derived materials, synthetic organic polymers, and various nanostructured carbons (e.g. carbon nanotubes, carbon nanofibers, carbon aerogels, carbide-derived carbons, graphene, etc.).
Abstract: Because of their availability, adjustable microstructure, varieties of forms, and large specific surface area, porous carbon materials are of increasing interest for use in hydrogen storage adsorbents and electrode materials in supercapacitors and lithium–sulfur cells from the viewpoint of social sustainability and environmental friendliness. Therefore, much effort has been made to synthesize and tailor the microstructures of porous carbon materials via various activation procedures (physical and chemical activation). In particular, the chemical activation of various carbon sources using KOH as the activating reagent is very promising because of its lower activation temperature and higher yields, and well-defined micropore size distribution and ultrahigh specific surface area up to 3000 m2 g−1 of the resulting porous carbons. In this feature article, we will cover recent research progress since 2007 on the synthesis of KOH-activated carbons for hydrogen and electrical energy storage (supercapacitors and lithium–sulfur batteries). The textural properties and surface chemistry of KOH-activated carbons depend on not only the synthesis parameters, but also different carbon sources employed including fossil/biomass-derived materials, synthetic organic polymers, and various nanostructured carbons (e.g. carbon nanotubes, carbon nanofibers, carbon aerogels, carbide-derived carbons, graphene, etc.). Following the introduction to KOH activation mechanisms and processing technologies, the characteristics and performance of KOH-activated carbons as well as their relationships are summarized and discussed through the extensive analysis of the literature based on different energy storage systems.
2,046 citations
TL;DR: In this article, the state of research for heterogeneous and homogeneous formic acid dehydrogenation catalysts is reviewed in detail and an outlook on necessary development steps is presented.
Abstract: Formic acid has recently been suggested as a promising hydrogen storage material. The basic concept is briefly discussed and the recent advances in the development of formic acid dehydrogenation catalysts are shown. Both the state of research for heterogeneous and for homogeneous catalyst systems are reviewed in detail and an outlook on necessary development steps is presented. Formic acid is considered as one of the most promising materials for hydrogen storage today. There are a number of highly active and robust homogeneous catalysts that selectively decompose formic acid to H2 and CO2 near to room temperature. Although the activity and selectivity of heterogeneous catalysts have not yet reached the level of homogeneous systems, this gap is closing.
929 citations
TL;DR: In this paper, a review article summarizes the recent research progress on the synthesis of nanostructured carbon and its application in energy storage and conversion, and the common challenges in developing simple, scalable, and environmentally friendly synthetic and manufacturing processes, in controlling the nanoscale and high level structures and functions, and in integrating such materials with suitable device architectures are reviewed.
868 citations
TL;DR: The first reversible and recyclable hydrogen storage system that operates under mild conditions using CO2, formate and formic acid is shown, which is energy-efficient and green because it operates near ambient conditions, uses water as a solvent, produces high-pressure CO-free hydrogen, and uses pH to control hydrogen production or consumption.
Abstract: Green plants convert CO2 to sugar for energy storage via photosynthesis. We report a novel catalyst that uses CO2 and hydrogen to store energy in formic acid. Using a homogeneous iridium catalyst with a proton-responsive ligand, we show the first reversible and recyclable hydrogen storage system that operates under mild conditions using CO2, formate and formic acid. This system is energy-efficient and green because it operates near ambient conditions, uses water as a solvent, produces high-pressure CO-free hydrogen, and uses pH to control hydrogen production or consumption. The extraordinary and switchable catalytic activity is attributed to the multifunctional ligand, which acts as a proton-relay and strong p-donor, and is rationalized by theoretical and experimental studies.
785 citations
TL;DR: A state-of-the-art review of the applications of hierarchically structured porous materials in energy conversion and storage is presented in this paper, where hierarchical porosity and structures have been heavily involved in newly developed energy storage and conversion systems, showing the importance of macrochannels in light related systems such as photocatalysis and photovoltaics.
Abstract: Materials with hierarchical porosity and structures have been heavily involved in newly developed energy storage and conversion systems. Because of meticulous design and ingenious hierarchical structuration of porosities through the mimicking of natural systems, hierarchically structured porous materials can provide large surface areas for reaction, interfacial transport, or dispersion of active sites at different length scales of pores and shorten diffusion paths or reduce diffusion effect. By the incorporation of macroporosity in materials, light harvesting can be enhanced, showing the importance of macrochannels in light related systems such as photocatalysis and photovoltaics. A state-of-the-art review of the applications of hierarchically structured porous materials in energy conversion and storage is presented. Their involvement in energy conversion such as in photosynthesis, photocatalytic H 2 production, photocatalysis, or in dye sensitized solar cells (DSSCs) and fuel cells (FCs) is discussed. Energy storage technologies such as Li-ions batteries, supercapacitors, hydrogen storage, and solar thermal storage developed based on hierarchically porous materials are then discussed. The links between the hierarchically porous structures and their performances in energy conversion and storage presented can promote the design of the novel structures with advanced properties.
784 citations
TL;DR: In this paper, the authors survey the research progress in hydrogen generation from liquid-phase chemical hydrogen storage materials and their regeneration, and present a review of these materials in hydrogen storage.
Abstract: In the search for future energy supplies, the application of hydrogen as an energy carrier is seen as a prospective issue. However, the implementation of a hydrogen economy is suffering from several unsolved problems. Particularly challenging is the storage of appropriate amounts of hydrogen. In this context one of the promising hydrogen storage techniques relies on liquid-phase chemical hydrogen storage materials, in particular, aqueous sodium borohydride, ammonia borane, hydrazine, hydrazine borane and formic acid. The use of these materials in hydrogen storage provides high gravimetric and volumetric hydrogen densities, low potential risk, and low capital investment because it is largely compatible with the current transport infrastructure. In this review, we survey the research progresses in hydrogen generation from these liquid-phase chemical hydrogen storage materials and their regeneration.
709 citations
TL;DR: In this paper, the authors presented porous carbon with hierarchical pore structure derived from highly crystalline metal organic frameworks (MOF-derived carbon: MDC) without any carbon source and showed it as a promising hydrogen storage adsorbent.
Abstract: Highly porous carbon has played an important role in tackling down the energy and environmental problems due to their attractive features such as high specific surface area (SSA), stability, and mass productivity. Especially, the desirable characteristics of the highly porous carbon such as lightweight, fast adsorption/desorption kinetics, and high SSA have attracted extensive attention in the “hydrogen storage” application which is a main bottleneck for the realization of on-board hydrogen fuel cell vehicles. We herein presented porous carbon with hierarchical pore structure derived from highly crystalline metal organic frameworks (denoted as MOF-derived carbon: MDC) without any carbon source and showed it as a promising hydrogen storage adsorbent. MDCs can be fabricated by a simple heat adjustment of MOFs without complicated process and environmental burden. The MDC displayed hierarchical pore structures with high ultramicroporosity, high SSA, and very high total pore volume. Due to its exceptional poro...
656 citations
TL;DR: The high selectivity toward CO(2) over N (2) and CH(4) makes the obtained polymer possess potential application in gas separation, and the synthesis route exhibits cost-effective advantages, which are essential for scale-up preparation.
Abstract: Microporous polycarbazole via straightforward carbazole-based oxidative coupling polymerization is reported. The synthesis route exhibits cost-effective advantages, which are essential for scale-up preparation. The Brunauer–Emmett–Teller specific surface area for obtained polymer is up to 2220 m2 g–1. Gas (H2 and CO2) adsorption isotherms show that its hydrogen storage can reach to 2.80 wt % (1.0 bar and 77 K) and the uptake capacity for carbon dioxide is up to 21.2 wt % (1.0 bar and 273 K), which show a promising potential for clean energy application and environmental field. Furthermore, the high selectivity toward CO2 over N2 and CH4 makes the obtained polymer possess potential application in gas separation.
635 citations
TL;DR: In this paper, the authors report on the synthesis and characterization of four new porous benzimidazole-linked polymers (BILPs) and evaluate their performance in small gas storage (H2, CH4, CO2) and selective CO2 binding over N2 and CH4.
Abstract: Porous organic polymers containing nitrogen-rich building units are among the most promising materials for selective CO2 capture and separation which can have a tangible impact on the environment and clean energy applications. Herein we report on the synthesis and characterization of four new porous benzimidazole-linked polymers (BILPs) and evaluate their performance in small gas storage (H2, CH4, CO2) and selective CO2 binding over N2 and CH4. BILPs were synthesized in good yields by the condensation reaction between aryl-o-diamine and aryl-aldehyde building blocks. The resulting BILPs exhibit moderate surface area (SABET = 599–1306 m2 g–1), high chemical and thermal stability, and remarkable gas uptake and selectivity. The highest selectivity based on initial slope calculations at 273 K was observed for BILP-2: CO2/N2 (113) and CO2/CH4 (17), while the highest storage capacity was recorded for BILP-4: CO2 (24 wt % at 273 K and 1 bar) and H2 (2.3 wt % at 77 K and 1 bar). These selectivities and gas uptake...
426 citations
TL;DR: In this paper, first-principles calculations were carried out to investigate lithium-dispersed two-dimensional carbon allotropes, viz. graphyne and graphdiyne, for their applications as lithium storage and hydrogen storage materials.
Abstract: Ab initio first-principles calculations were carried out to investigate lithium-dispersed two-dimensional carbon allotropes, viz. graphyne and graphdiyne, for their applications as lithium storage and hydrogen storage materials. The lithiation potentials (vs Li/Li+) and specific capacities in these materials are found to be enhanced considerably as compared to the conventional graphite-based electrode materials. Lithium metal binding to these carbon materials is found to be enhanced considerably and is more than the cohesive energy of lithium. Each lithium atom in these metal-dispersed materials is found to carry nearly one unit positive charge and bind molecular hydrogen with considerably improved adsorption energies. Our calculated hydrogen adsorption enthalpies (−3.5 to −2.8 kcal/mol) are very close to the optimum adsorption enthalpy proposed for ambient temperature hydrogen storage (−3.6 kcal/mol). We have also shown that the band gaps in these planar carbon allotropes can be tuned by varying the numb...
TL;DR: In this paper, the authors reviewed the recent progress toward low-cost, large capacity and light-weight on high pressure gaseous hydrogen storage vessels and proposed some suggestions on the further research.
TL;DR: The first example of reversible magnesium deposition/stripping onto/from an inorganic salt was seen for a magnesium borohydride electrolyte that was utilized in a rechargeable magnesium battery.
Abstract: Beyond hydrogen storage: The first example of reversible magnesium deposition/stripping onto/from an inorganic salt was seen for a magnesium borohydride electrolyte. High coulombic efficiency of up to 94 % was achieved in dimethoxyethane solvent. This Mg(BH_4)_2 electrolyte was utilized in a rechargeable magnesium battery.
TL;DR: In this article, a copper-based metal organic framework named HKUST-1 with fine structural analyses has been investigated for hydrogen storage capacity and it has shown that this material can store 0.47% of H 2 at 303 K and 35 bar.
TL;DR: A nexus between the catalyst support and catalyst particles is believed to yield the high hydrogen uptake capacities obtained.
Abstract: A high hydrogen storage capacity for palladium decorated nitrogen-doped hydrogen exfoliated graphene nanocomposite is demonstrated under moderate temperature and pressure conditions. The nitrogen doping of hydrogen exfoliated graphene is done by nitrogen plasma treatment, and palladium nanoparticles are decorated over nitrogen-doped graphene by a modified polyol reduction technique. An increase of 66% is achieved by nitrogen doping in the hydrogen uptake capacity of hydrogen exfoliated graphene at room temperature and 2 MPa pressure. A further enhancement by 124% is attained in the hydrogen uptake capacity by palladium nanoparticle (Pd NP) decoration over nitrogen-doped graphene. The high dispersion of Pd NP over nitrogen-doped graphene sheets and strengthened interaction between the nitrogen-doped graphene sheets and Pd NP catalyze the dissociation of hydrogen molecules and subsequent migration of hydrogen atoms on the doped graphene sheets. The results of a systematic study on graphene, nitrogen-doped g...
TL;DR: In this paper, the authors reviewed the methods used by the authors to synthesize Mg-based hydrogen storage materials with nanostructure as well as some novel techniques from other researchers, and focus on how these nanotechnology processing methods could change kinetics and thermodynamics in Mgbased materials for hydrogen storage.
TL;DR: The strong efforts devoted to the exploration of BNH compounds for hydrogen storage have led to impressive advances in the field of boron chemistry as mentioned in this paper, and a review summarizes progress in this field from three aspects.
Abstract: The strong efforts devoted to the exploration of BNH compounds for hydrogen storage have led to impressive advances in the field of boron chemistry. This review summarizes progress in this field from three aspects. It starts with the most recent developments in using BNH compounds for hydrogen storage, covering NH3BH3, B3H8− containing compounds, and CBN compounds. The following section then highlights interesting applications of BNH compounds in hydrogenation and catalysis. The last part is focused on breakthroughs in the syntheses and discovery of new BNH organic analogues. The role of N–Hδ+⋯Hδ−–B dihydrogen interactions in molecule packing, thermal hydrogen evolution, and syntheses is also discussed within the review.
TL;DR: Hydrous hydrazine (N2H4·H2O) is considered as a promising liquid hydrogen storage material owing to the high content of hydrogen and the advantage of CO-free H2 produced.
Abstract: Storing hydrogen safely and efficiently is one of the major technological barriers preventing the widespread application of hydrogen-fueled cells, such as proton exchange membrane fuel cells (PEMFCs). Hydrous hydrazine (N2H4·H2O) is considered as a promising liquid hydrogen storage material owing to the high content of hydrogen (7.9%) and the advantage of CO-free H2 produced. [1] In particular, hydrous hydrazine offers great potential as a hydrogen storage material for some special applications, such as unmanned space vehicles and submarine power sources, where hydrazine is usually used as a propellant. The decomposition of hydrazine proceeds by two typical reaction routes:
TL;DR: In this article, a rhodium-nickel nanoparticles grown on graphene are successfully synthesized by coreduction of graphene oxide and metal precursors, wherein graphene proved to be a powerful dispersion agent and distinct support for the RhNi nanoparticles.
Abstract: Well-dispersed rhodium–nickel nanoparticles grown on graphene are successfully synthesized by co-reduction of graphene oxide and metal precursors, wherein graphene proved to be a powerful dispersion agent and distinct support for the RhNi nanoparticles. Unexpectedly, the resultant RhNi@graphene catalyst exerts 100% selectively and exceedingly high activity to complete the decomposition reaction of hydrous hydrazine at room temperature. This excellent catalytic performance might be due to the synergistic effect of the graphene support and the RhNi nanoparticles and the promotion effect of NaOH. The utilization of graphene as a novel two-dimensional catalyst support to anchor active component nanoparticles and thus to facilitate the electron transfer and mass transport kinetics during the catalytic reaction process opens up new avenues for designing next-generation catalysts.
TL;DR: A review of hydrogen storage materials can be found in this article, where the very basic aspects of the hydrogen storage are presented and the promise of state-of-the-art candidates is indicated.
TL;DR: These monodisperse palladium (Pd) nanoparticles on reduced graphene oxide (RGO) surfaces were successfully prepared by a "wet" and "clean" method in aqueous solution and exhibited catalytic activity in hydrogen generation from the hydrolysis of ammonia borane.
Abstract: In this study, monodisperse palladium (Pd) nanoparticles on reduced graphene oxide (RGO) surfaces were successfully prepared by a “wet” and “clean” method in aqueous solution. Without any surface treatment, Pd nanoparticles are firmly attached to the RGO sheets. These RGO/Pd nanocomposites exhibited catalytic activity in hydrogen generation from the hydrolysis of ammonia borane (AB). Their hydrolysis completion time and activation energy were 12.5 min and 51 ± 1 kJ mol−1, respectively, which were comparable to the best Pd-based catalyst reported. The TOF values (mol of H2 × (mol of catalyst × min)−1) of RGO/Pd is 6.25, which appears to be one of the best catalysts reported so far. We also obtained a 11B NMR spectrum to investigate the mechanism of this catalytic hydrolysis process. This simple and straightforward method is of significance for the facile preparation of metal nanocatalysts with high catalytic activity on proper supporting materials.
TL;DR: In this paper, five metal-organic frameworks (MOFs, termed MOF-324, 325, 326 and IRMOF-61 and 62) were characterized by single-crystal X-ray diffraction, and their low-pressure and high-pressure hydrogen uptake properties were investigated.
Abstract: Five new metal–organic frameworks (MOFs, termed MOF-324, 325, 326 and IRMOF-61 and 62) of either short linkers (pyrazolecarboxylate and pyrazaboledicarboxylate) or long and thin alkyne functionalities (ethynyldibenzoate and butadiynedibenzoate) were prepared to examine their impact on hydrogen storage in MOFs. These compounds were characterized by single-crystal X-ray diffraction, and their low-pressure and high-pressure hydrogen uptake properties were investigated. In particular, volumetric excess H2 uptake by MOF-324 and IRMOF-62 outperforms MOF-177 up to 30 bar. Inelastic neutron-scattering studies for MOF-324 also revealed strong interactions between the organic links and hydrogen, in contrast to MOF-5 where the interactions between the Zn4O unit and hydrogen are the strongest. These data also show that smaller pores and polarized linkers in MOFs are indeed advantageous for hydrogen storage.
TL;DR: In this article, the authors evaluated the performance of two sorption-based hydrogen storage systems, one using AX-21, a high surface-area superactivated carbon, and the other using MOF-177, a metal-organic framework material.
TL;DR: In this article, a template-free solid state synthesis route was developed by which BN hollow spheres (BNHSs) with ultrathin shells (1-3 nm) were successfully prepared.
Abstract: We developed a facile template-free solid state synthesis route, by which BN hollow spheres (BNHSs) with ultrathin shells (1–3 nm) were successfully prepared. Furthermore, the shell thickness of the BNHSs could be effectively adjusted by varying the reaction temperature. The as-prepared BNHSs with ultrathin shells possess high specific surface area, large pore volume and high density structural defects. These characteristics result in the excellent performance of BNHSs in hydrogen storage and adsorption of organic pollutants from wastewater. The hydrogen uptake capacity is up to 4.07 wt.% at 298 K and 10 MPa. The maximum adsorption capacities for basic yellow 1 and methylene blue are 191.7 and 116.5 mg g−1, respectively. Besides, the BNHSs preferentially adsorb organic aromatic compounds from mixed solutions of aromatic dyes and heavy metal ions, so they can be used to separate and recover some valuable organic compounds from wastewater.
TL;DR: A commercially available zeolitic imidazolate framework (ZIF), namely Basolite Z1200 (BASF), has been used as template for nanocasting of highly microporous ZIF-templated carbon as discussed by the authors.
Abstract: A commercially available zeolitic imidazolate framework (ZIF), namely Basolite Z1200 (BASF), has been used as template for nanocasting of highly microporous ZIF-templated carbon. The “hard template carbonization technique” consists of liquid impregnation of furfuryl alcohol into the pores of the ZIF followed by polymerization and then carbonization during which the ZIF template is removed to generate the microporous carbon (90–95% microporosity) with a surface area of 900–1100 m2 g−1 and a pore volume of ca. 0.7 cm3 g−1. Chemical activation (with KOH at a relatively low temperature of 700 °C for 1 h and a carbon/KOH weight ratio of 1 : 4) of the ZIF-templated carbons increases their porosity by between 30 and 240% depending on their carbonization temperature, to achieve a surface area of up to 3200 m2 g−1 and a pore volume of 1.94 cm3 g−1. Despite the drastic increase in porosity, the activated ZIF-templated carbons retain significant microporosity with micropores contributing 80–90% of surface area and 60–70% of pore volume. This occurs because the activation process mainly enhances existing porosity rather than creating new larger pores. The activation enhances the hydrogen uptake capacity of the ZIF-templated carbons by between 25 and 140% from 2.6–3.1 wt% to the range 3.9–6.2 wt% (at −196 °C and 20 bar). The increase in hydrogen uptake after activation is closely related to rises in the micropore surface area and micropore volume rather than overall increase in porosity. Due to their microporous nature, the carbons exhibit high hydrogen storage density in the range 13.0–15.5 μmol H2 m−2, which is much higher than that of most high surface area activated carbons.
TL;DR: Recent advances in the field of chemical hydrogen storage that couples lightweight materials and nanostructures, focusing on Mg/MgH(2)-based systems are reviewed, with the emphasis on illustrating the influences of nanostructure on the hydrogenation/dehydrogenation mechanisms and hydrogen storage properties such as capacity, thermodynamics and kinetics.
TL;DR: Recently, carbon nanomaterials decorated with Ca atoms as attractors of H2 molecules have been suggested as room temperature hydrogen storage media because of their large surface area and low weigh as discussed by the authors.
Abstract: Recently, carbon nanomaterials decorated with Ca atoms as attractors of H2 molecules have been suggested as room temperature hydrogen storage media because of their large surface area and low weigh...
TL;DR: It is demonstrated that NaAlH(4) confined within the nanopores of a titanium-functionalized metal-organic framework (MOF) template MOF-74(Mg) can reversibly store hydrogen with minimal loss of capacity and allow rehydriding to be almost fully reversible.
Abstract: We demonstrate that NaAlH4 confined within the nanopores of a titanium-functionalized metal–organic framework (MOF) template MOF-74(Mg) can reversibly store hydrogen with minimal loss of capacity. Hydride-infiltrated samples were synthesized by melt infiltration, achieving loadings up to 21 wt %. MOF-74(Mg) possesses one-dimensional, 12 A channels lined with Mg atoms having open coordination sites, which can serve as sites for Ti catalyst stabilization. MOF-74(Mg) is stable under repeated hydrogen desorption and hydride regeneration cycles, allowing it to serve as a “nanoreactor”. Confining NaAlH4 within these pores alters the decomposition pathway by eliminating the stable intermediate Na3AlH6 phase observed during bulk decomposition and proceeding directly to NaH, Al, and H2, in agreement with theory. The onset of hydrogen desorption for both Ti-doped and undoped nano-NaAlH4@MOF-74(Mg) is ∼50 °C, nearly 100 °C lower than bulk NaAlH4. However, the presence of titanium is not necessary for this increase i...
TL;DR: In this paper, a Ru-catalyzed hydrogenation of carbon dioxide proceeds with an unprecedented high formic acid to amine ratio (AAR of 2.69), which results in an improved energy content.
Abstract: A novel Ru-catalyzed hydrogenation of carbon dioxide proceeds with an unprecedented high formic acid to amine ratio (AAR of 2.69), which results in an improved energy content. The presented catalyst system allows for reversible fast hydrogen loading (even at RT) and unprecedented unloading (TON for H2 liberation of 800000).
TL;DR: In this article, the authors synthesized MOF-5-based composites containing 1-10% expanded natural graphite (ENG) and evaluated their properties with regard to thermal conductivity, specific heat capacity, surface area, and crystallinity.