Cyclopentadienyl chromium hydrazide gels for Kubas-type hydrogen storage

Hung, V.; Hoang, Tuan K.A.; Hamaed, Ahmad; Antonelli, David M.

doi:10.1039/c001964j

Cited by 19 publications

(30 citation statements)

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“…The presence of residual carbon ranging from 5.11% to 7.89% in these samples indicates that hydrogenation was not effective in removing the last traces of hydrocarbon, possibly due to trapping of the tetramethylsilane byproduct in the pore structure. The nitrogen values are also lower than expected, likely due to the combination of residual hydrocarbon and nitride formation on combustion, which has been observed in our previous hydrazide materials 17,18 and is often observed in the elemental analysis of early transition metal organometallics.…”

Section: ' Experimental Sectionmentioning

confidence: 68%

“…Previous work on metal hydrazides17,18 has shown that in general the energy of the N1s emission in bound M x NH y species increases as M is substituted for H and also as the coordination number of N increases from 3 to 4. Thus, the emission at 396.2 eV likely corresponds to a CrÀNÀCr species created by a double protolysis or a CrdN species formed by a single protolysis followed by an α-migration of the remaining NÀH to the metal center to form a CrÀH.…”

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confidence: 99%

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Hydride-Induced Amplification of Performance and Binding Enthalpies in Chromium Hydrazide Gels for Kubas-Type Hydrogen Storage

et al. 2011

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Hydrogen is the ideal fuel because it contains the most energy per gram of any chemical substance and forms water as the only byproduct of consumption. However, storage still remains a formidable challenge because of the thermodynamic and kinetic issues encountered when binding hydrogen to a carrier. In this study, we demonstrate how the principal binding sites in a new class of hydrogen storage materials based on the Kubas interaction can be tuned by variation of the coordination sphere about the metal to dramatically increase the binding enthalpies and performance, while also avoiding the shortcomings of hydrides and physisorpion materials, which have dominated most research to date. This was accomplished through hydrogenation of chromium alkyl hydrazide gels, synthesized from bis(trimethylsilylmethyl) chromium and hydrazine, to form materials with low-coordinate Cr hydride centers as the principal H(2) binding sites, thus exploiting the fact that metal hydrides form stronger Kubas interactions than the corresponding metal alkyls. This led to up to a 6-fold increase in storage capacity at room temperature. The material with the highest capacity has an excess reversible storage of 3.23 wt % at 298 K and 170 bar without saturation, corresponding to 40.8 kg H(2)/m(3), comparable to the 2015 DOE system goal for volumetric density (40 kg/m(3)) at a safe operating pressure. These materials possess linear isotherms and enthalpies that rise on coverage, retain up to 100% of their adsorption capacities on warming from 77 to 298 K, and have no kinetic barrier to adsorption or desorption. In a practical system, these materials would use pressure instead of temperature as a toggle and can thus be used in compressed gas tanks, currently employed in the majority of hydrogen test vehicles, to dramatically increase the amount of hydrogen stored, and therefore range of any vehicle.

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Section: ' Experimental Sectionmentioning

confidence: 68%

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confidence: 99%

Hydride-Induced Amplification of Performance and Binding Enthalpies in Chromium Hydrazide Gels for Kubas-Type Hydrogen Storage

et al. 2011

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“…Brunauer-Emmett-Teller (BET) surface area up to 106 m 2 g -1 , significantly lower than the surface areas of most MOFs, activated carbons but comparable to the value of metal hydrazide gel materials (90-550 m 2 g -1 ) [1,[38][39][40] . The Density Functional Theory (DFT) pore size distributions of the PTF-Fe complex derived using the entire range of the N 2 adsorption isotherms confirm that the size of the majority of pores is about 1.5 nm, which is beneficial for H 2 gas adsorption due to the strong host-H 2 interaction originated from the overlap of the pore wall potentials (Figure 3c) [41] .…”

Section: Resultsmentioning

confidence: 93%

“…Interestingly, at 298 K and a pressure within 100 atm, these materials show a straight adsorption line due to the weak host-H 2 interaction. On the other hand, the Kubas type metal hydrazide gel materials [19] show a straight adsorption line both at 77 K and 298 K within pressures of 100 atm suggesting different adsorption behaviour with relatively stronger host-H 2 interaction [38][39][40] . Similarly, the PTF-Fe complex exhibits a straight adsorption line both at 77 K and 298 K (Figure 4a and 4b).…”

Section: Resultsmentioning

confidence: 97%

Hydrogen Storage in a Crosslinked Phloroglucinol-Terephthalaldehyde Framework with Exposed Iron Sites

Pareek¹,

Rohan²,

Cheng³

2017

Res. Rev. J Mat. Sci

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The rapid consumption of fossil fuels worldwide has escalated greenhouse emission to a unsustainable level and has inspired the global research community to search for alternative energy resources [1]. Hydrogen is an environmentally clean and efficient energy carrier for a wide variety of applications [2]. Unfortunately, lack of safe, high density hydrogen storage methods at near ambient conditions has been deemed to be the bottleneck that prevents broad market acceptance of hydrogen technologies. Technically, hydrogen storage can be realized via chemisorption [3] in the form of chemical hydrides [4] , complex hydrides [3] , or physisorption [1] in porous carbon based materials [5] , zeolites [6] , metal organic frameworks (MOFs) [1,7,8] and porous organic frameworks (POFs) [9-15]. Nevertheless, most of the chemisorptionbased materials exhibit relatively poor kinetics and require an elevated temperature to release the hydrogen gas [3] , while most of the physisorption-based materials show fast adsorption-desorption kinetics but negligible hydrogen storage capacity at ambient temperature due to the weak host-H 2 interaction in the range of 3-7 kJ mol-1 [16]. It has been shown that hydrogen storage capacity in physisorption-based materials can be improved if the associated enthalpy of adsorption is enhanced in the range of 15-20 kJ mol-1 , which is substantially higher than the typical van der Waals force [17]. To enhance H 2 affinity in a host material via physisorption, extensive research efforts have been made to develop materials with coordinatively unsaturated metal sites. The metal elements selected are chiefly from the first row of transition metal series due to their unique capabilities to stabilize the M- 2-H 2 complexes via electron backdonation from metal d-orbitals to the antibonding orbital of H 2 (σ*) and to accommodate several H 2 molecules per each metal atom [18,19]. For example, in a phloroglucinol-terephthalaldehyde based framework with coordinatively unsaturated Cr metals, a high excess hydrogen uptake up to 1.5 wt% at 298 K and 100 atm with an isosteric heat of adsorption (Qst) up to 11.5 kJ mol-1 has been reported recently by our group [18]. Sumida et al. [20] also demonstrated a high Qst of 11.9 kJ mol-1 on coordinatively unsaturated iron metal sites in Fe-BTT MOF (BTT 3-=1,3,5-benzenetristetrazolate). Similar observations have also been made in several recent studies [21,22]. In this work, we report hydrogen storage with a significant capacity in a mesoporous phloroglucinol-terephthalaldehyde framework compound decorated with exposed iron atoms (PTF-Fe) [23] .

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“…26 Recently, substantial development has been made in exploiting the applications of organometallic dihydrogen compounds for hydrogen storage. [27][28][29][30][31] For example, chromium hydrazide gels 31 Intriguingly, such kinds of metal-alkyl hydrazide gel could use pressure instead of temperature as a toggle, rendering them applicable to currently employed compressed gas tanks.…”

Section: Background and Introductionmentioning

confidence: 99%

Efficient hydrogen storage with the combination of lightweight Mg/MgH2 and nanostructures

et al. 2012

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Efficient hydrogen storage plays a key role in realizing the incoming hydrogen economy. However, it still remains a great challenge to develop hydrogen storage media with high capacity, favourable thermodynamics, fast kinetics, controllable reversibility, long cycle life, low cost and high safety. To achieve this goal, the combination of lightweight materials and nanostructures should offer great opportunities. In this article, we review recent advances in the field of chemical hydrogen storage that couples lightweight materials and nanostructures, focusing on Mg/MgH(2)-based systems. Selective theoretical and experimental studies on Mg/MgH(2) nanostructures are overviewed, with the emphasis on illustrating the influences of nanostructures on the hydrogenation/dehydrogenation mechanisms and hydrogen storage properties such as capacity, thermodynamics and kinetics. In particular, theoretical studies have shown that the thermodynamics of Mg/MgH(2) clusters below 2 nm change more prominently as particle size decreases.

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Cyclopentadienyl chromium hydrazide gels for Kubas-type hydrogen storage

Cited by 19 publications

References 38 publications

Hydride-Induced Amplification of Performance and Binding Enthalpies in Chromium Hydrazide Gels for Kubas-Type Hydrogen Storage

Hydride-Induced Amplification of Performance and Binding Enthalpies in Chromium Hydrazide Gels for Kubas-Type Hydrogen Storage

Hydrogen Storage in a Crosslinked Phloroglucinol-Terephthalaldehyde Framework with Exposed Iron Sites

Efficient hydrogen storage with the combination of lightweight Mg/MgH2 and nanostructures

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