Reversible ammonia-based and liquid organic hydrogen carriers for high-density hydrogen storage: Recent progress

Makepeace, Joshua W.; He, Teng; Weidenthaler, Claudia; Jensen, Torben R.; Chang, Fei; Vegge, Tejs; Ngene, Peter; Kojima, Yoshitsugu; Jongh, Petra E. de; Chen, Ping; David, William I. F.

doi:10.1016/j.ijhydene.2019.01.144

Cited by 204 publications

(124 citation statements)

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“…Reversible hydrogen absorption and desorption over complex hydrides would involve surface H–H dissociation/recombination, ion diffusion and bulk‐phase reconfiguration, etc., creating a situation that is distinctly different from the conventional heterogeneous catalysis on TM surfaces. Albeit the structural and electronic properties of the surface of complex hydrides have yet to be systematically explored, some encouraging progress in using complex hydrides as catalysts has been made very recently and will be briefed in this section.…”

Section: Complex Hydrides For Catalysismentioning

confidence: 99%

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Complex Hydrides for Energy Storage, Conversion, and Utilization

2019

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functionalities and exhibit great potentials for the applications in the energy transfer chain (Figure 1).In chemistry, a hydride is a compound having negatively charged hydrogen anion. [2] Nowadays, however, hydrogenous compounds having hydrogen bonded to metals or nonmetal in ionic, metallic or covalent manner are collectively referred as hydrides. [3] Complex hydride is such a class of compound having a general formula of M(XH n ) m , where M is usually a metal cation and X is a metal or nonmetal element which sets up covalent or ionocovalent bonding with H. [4] The M[XH n ] m is H-rich and can decompose selectively to H 2 allowing complex hydrides of light-weight elements potential hydrogen storage media. As a matter of fact, since the pioneering work of Ti-catalyzed NaAlH 4 in 1997, [5] extensive investigations on hydrogen storage over alanates, [6] amide-hydride composites, [7] borohydrides, [8] amidoboranes [9] as well as metallorganic hydrides [10] were carried out and tremendous progress has been made (Figure 2). [1,4a] The break and setup of XH bonding would be endergonic and exergonic, respectively. The energy input and output in hydrogen desorption and reabsorption over a complex hydride depends strongly on its thermodynamic stability, which also offers an opportunity of using complex hydrides as thermal energy storage materials to cope up with the intermittent, fluctuating and unstable supply of renewable energies. Owning to their exclusive advantages of diversity, high energy densities and tunability, complex hydrides have been actively pursued for this application since year 2000. [11] Solid electrolytes with fast conduction of Li, Na, or Mg ions are highly demanded for all-solid-state batteries with high energy density and safety. Coincidentally, complex hydrides are composed of those cations and a relatively large sized [XH n ] anion. The coordination flexibility of the large anion with alkali or alkaline earth cation would create some favorable structural features, such as defects and/or low-barrier diffusion channels, to facilitate cation migration within the lattice of complex hydrides. [12] Starting from the finding of high Li-ion conduction in the high-temperature-phase LiBH 4 , [13] a variety of complex hydrides has been developed, some of which show superior ion conductivity to their nonhydride peers. [14] Hydrogen storage over complex hydride would undergo dihydrogen dissociation into surface H atoms followed by H Functional materials are the key enabling factor in the development of clean energy technologies. Materials of particular interest, which are reviewed herein, are a class of hydrogenous compound having the general formula of M(XH n ) m , where M is usually a metal cation and X can be Al, B, C, N, O, transition metal (TM), or a mixture of them, which sets up an iono-covalent or covalent bonding with H. M(XH n ) m is generally termed as a complex hydride by the hydrogen storage community. The rich chemistry between H and B/C/N/O/Al/TM allows complex hydrides of diverse compo...

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Section: Complex Hydrides For Catalysismentioning

confidence: 99%

“…NH 3 , the second largest man‐made chemical, has been seriously considered as an energy (hydrogen) carrier in recent years 160a,161. Producing and decomposing ammonia under mild conditions have been pursued for a century and now regain momentum .…”

Section: Complex Hydrides For Catalysismentioning

confidence: 99%

Complex Hydrides for Energy Storage, Conversion, and Utilization

2019

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“…The higher number of methine units protruding into the small tetrahedral pore and the small dodecahedral pore result in an increased affinity for hydrocarbon molecules at low pressures to become adsorbed within the framework. Interestingly, the adsorption of cyclohexane at low pressures is greatly favored over the adsorption of benzene, unprecedented in MOF research and potentially addressing a common low pressure separation issue in the hydrogen transfer industry . The remarkable hydrocarbon separation properties that have emerged from this research verifies the important influence a contoured pore environment has on the behavior of the overall framework.…”

Section: Resultsmentioning

confidence: 79%

Enhancing Multicomponent Metal–Organic Frameworks for Low Pressure Liquid Organic Hydrogen Carrier Separations

et al. 2020

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The resurgence of interest in the hydrogen economy could hinge on the distribution of hydrogen in a safe and efficient manner. Whilst great progress has been made with cryogenic hydrogen storage or liquefied ammonia, liquid organic hydrogen carriers (LOHCs) remain attractive due to their lack of need for cryogenic temperatures or high pressures, most commonly a cycle between methylcyclohexane and toluene. Oxidation of methylcyclohexane to release hydrogen will be more efficient if the equilibrium limitations can be removed by separating the mixture. This report describes a family of six ternary and quaternary multicomponent metal–organic frameworks (MOFs) that contain the three‐dimensional cubane‐1,4‐dicarboxylate (cdc) ligand. Of these MOFs, the most promising is a quaternary MOF (CUB‐30), comprising cdc, 4,4′‐biphenyldicarboxylate (bpdc) and tritopic truxene linkers. Contrary to conventional wisdom that adsorptive interactions with larger, hydrocarbon guests are dominated by π–π interactions, here we report that contoured aliphatic pore environments can exhibit high selectivity and capacity for LOHC separations at low pressures. This is the first time, to the best of our knowledge, where selective adsorption for cyclohexane over benzene is witnessed, underlining the unique adsorptive behavior afforded by the unconventional cubane moiety.

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“…More precisely, the ammonia produced during urea photodegradation could be used inside space stations as direct fuel for combustion and fuel cells [34,35]. In fact, the ease of storage of ammonia in comparison to hydrogen [36] makes it suitable to be used as an alternative fuel because of its high energy density (12.6 MJ L −1 ), especially for space stations. The idea to achieve resource recovery from water recycling systems was already developed as a proof of concept by Nicolau et al [37] who based their recycling system on the use of a bioreactor that was able to produce a high amount of ammonia, which was used to feed an electrochemical cell in order to generate electrical energy.…”

Section: Influence Of Visible Light Modulation Techniques On Urea Phomentioning

confidence: 99%

Use of Visible Light Modulation Techniques in Urea Photocatalytic Degradation

Vaiano

Sacco

Capua

et al. 2019

Water

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The aim of this work was to analyze the effect of visible LED dimming duty-cycle modulation techniques in a photocatalytic system for urea degradation using a visible light photocatalyst immobilized on macroscopic supports. For this reason, the effect of different LED dimming techniques was investigated and compared in terms of urea degradation together with ammonia and nitrate production during the irradiation time. The experimental results evidenced that using a visible LED dimming modulation with variable-peak variable-duty pulse-width modulation (PWM) allows to improve the photocatalytic degradation process, with respect to classical LED dimming with fixed-peak fixed-duty PWM, and influences the product's distribution of ammonia and nitrate in water. Therefore, the proof of concept herein proposed could be considered as preliminary potential results to be used in water recycling applications with a particular emphasis in recovery of urea photodegradation byproducts, such as ammonia, from wastewater that could be used as potential resources and an energy resource.

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Reversible ammonia-based and liquid organic hydrogen carriers for high-density hydrogen storage: Recent progress

Cited by 204 publications

References 183 publications

Complex Hydrides for Energy Storage, Conversion, and Utilization

Complex Hydrides for Energy Storage, Conversion, and Utilization

Enhancing Multicomponent Metal–Organic Frameworks for Low Pressure Liquid Organic Hydrogen Carrier Separations

Use of Visible Light Modulation Techniques in Urea Photocatalytic Degradation

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