Kinetic investigation of the catalytic effect of a body centered cubic-alloy TiV1.1Mn0.9 (BCC) on hydriding/dehydriding properties of magnesium

Yonkeu, A.; Swainson, I. P.; Dufour, Javier; Huot, Jacques

doi:10.1016/j.jallcom.2007.06.016

Cited by 20 publications

(10 citation statements)

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“…In this type of composites, Yonkeu et al showed that the hydrogenation kinetics is controlled by a three-dimensional growth of the hydride phase and the diffusion of hydrogen through the hydride phase. In contrast, the dehydrogenation kinetics is governed by the bulk/surface nucleation and two dimensional growth of the magnesium phase with a constant velocity of the Mg/MgH 2 interface [30]. Yu et al suggested that the hydrogenated bcc alloy showed superior catalytic properties compared to the quenched bcc alloy in magnesium composites because the hydrogenation induces the formation of micro/nanosized additive particles [31] which greatly enhance the hydrogen atomic diffusivity.…”

Section: Introductionmentioning

confidence: 99%

“…Yu et al suggested that the hydrogenated bcc alloy showed superior catalytic properties compared to the quenched bcc alloy in magnesium composites because the hydrogenation induces the formation of micro/nanosized additive particles [31] which greatly enhance the hydrogen atomic diffusivity. Thus, in order to provide insight into the catalytic role of the bcc additive in MgH 2 composites, previous studies have addressed microstructural [18], kinetical [30,32] and thermodynamical issues [16]. In this paper we investigate, in operando, the structural evolution of a TiVCr-MgH 2 composite upon hydrogenation and dehydrogenation.…”

Section: Introductionmentioning

confidence: 99%

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In operando study of TiVCr additive in MgH2 composites

Laversenne

Andrieux

Planté

et al. 2013

International Journal of Hydrogen Energy

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

In operando study of TiVCr additive in MgH2 composites

Laversenne

Andrieux

Planté

et al. 2013

International Journal of Hydrogen Energy

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“…The catalytic enhancement of hydrides has been widely demonstrated 11 ; however, most studies involve several hours of ball milling. For example, Yonkeu et al 32 showed that 80 h of ball milling was needed to decrease the T dec of MgH 2 from 429.2 to 368.3°C using 2 mol% of the bodycentered cubic alloy TiV 1.1 Mn 0.9 as catalyst. We should note that for studies performed in vacuum, T dec of modified MgH 2 in the range of 200-280°C with a good rate is common while at 0.1 Mpa H 2 , no desorption occurs below 325°C.…”

Section: B Influence Of Ni-based Catalystsmentioning

confidence: 99%

Catalytic influence of Ni-based additives on the dehydrogenation properties of ball milled MgH₂

et al. 2011

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The catalytic influence of Ni, Zr 2 Ni 5 , and LaNi 5 on the dehydrogenation properties of milled MgH 2 was investigated. MgH 2 milled in the presence of Ni (5 wt%) and Zr 2 Ni 5 (5 wt%) catalysts for 2 h showed apparent activation energies, E A , of 81 and 79 kJ/mol, respectively, corresponding to ;50% decrease in E A and a moderate decrease (;100°C) in the decomposition temperature (T dec ). A further 27°C decrease in T dec was observed after milling with 10 wt%Ni. Based on the E A values, the catalytic activity decreased in the following order: Ni % Zr 2 Ni 5 . LaNi 5 . X-ray photoelectron spectroscopy analysis of the milled and dehydrogenated states of the hydrides modified with Ni catalyst revealed that the observed reduction in E A may be due to the ability of Ni catalyst to decrease the amount of oxygen atoms in defective positions that are capable of blocking catalytically active sites thereby enhancing the dehydrogenation kinetics. In particular, our results reveal a strong correlation between the type of oxygen species adsorbed on Ni-modified MgH 2 and the E A of the dehydrogenation reaction.

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“…The literature is replete with studies on the catalytic enhancement of hydrides [11], however most studies involve several hour of ball milling. For example, Yonkeu et al [15 Next, we examine the effect of Ni-based catalysts on the dehydrogenation kinetics of MgH 2 . The apparent activation energies, E A being determined using the Kissinger method as previously discussed (Figure 5).…”

Section: Figure 2 -Fesem Images Of (A) As-received Mgh 2 Showing the mentioning

confidence: 99%

Agile Thermal Management STT-RX, Modified Magnesium Hydride and Calcium Borohydride for High-Capacity Thermal Energy Storage (PREPRINT)

Amama¹,

Spowart²,

Voevodin³

et al. 2011

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information SPONSORING/MONITORING AGENCY REPORT NUMBER(S) AFRL-RX-WP-TP-2011-4419 DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution unlimited. SUPPLEMENTARY NOTESThe U.S. Government is joint author of this work and has the right to use, modify, reproduce, release, perform, display, or disclose the work. PA Case Number and clearance date: 88ABW-2011-0884, 01 Mar 2011. Preprint journal article to be submitted to Proceedings of the ASME/JSME 2011 8 th Thermal Engineering Joint Conference, March 13-17, 2011, Honolulu, Hawaii, USA. This document contains color. © 2011 by ASME. ABSTRACTMgH 2 , and Ca(BH 4 ) 2 are potential thermal energy storage (TES) materials that possess extraordinarily high inherent thermal energy densities of up to 2 MJ/kg. However, the high desorption temperatures at atmospheric pressure [>300°C for Ca(BH 4 ) 2 , >400°C for MgH 2 ] coupled with slow kinetics represent significant challenges for their use in TES. In order to address these challenges, the present work focuses on the development of new modification approaches based on nanostructuring via high-energy vibratory ball milling and catalytic enhancement using pure Ni and Ni alloys. Our work reveals that high-energy vibrating-mill technique with ball-to-powder weight ratio as low as 13:1 can produce MgH 2 powders with nanocrystallites after 2h of milling. MgH 2 milled with Ni (5 wt%) and Ni 5 Zr 2 (5 wt%) catalysts for 2 h showed apparent activation energies, E A of 81 and 79 kJ/mo1, respectively, corresponding to ~50% decrease in E A and~100%°C decrease in the decomposition temperature (T dec ). On the other hand, the decomposition reaction of Ca(BH 4 ) 2 does not seem to be catalyzed by the Ni-based catalysts tested. SUBJECT TERMS INTRODUCTIONThe development of novel and efficient thermal energy storage (TES) materials remains a major challenge in addressing needs in a variety of areas from intermittent solar energy harvesting to thermal management of transient, highflux heat loads. A variety of passive materials have been developed and employed for TES including paraffin waxes, water tanks, and low-capacity reversible metal hydrides, among others. Paraffin wax has been used as a TES medium for decades [1,2,3,4]. However, the current state-of-art packaging technology for paraffin wax reduces the system level heat storage capacity by 75%, i.e. from 250 kJ/kg down to 65 kJ/kg. Other material systems of possible interest are summarized in Table 1; notably, paraffins and li...

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Kinetic investigation of the catalytic effect of a body centered cubic-alloy TiV1.1Mn0.9 (BCC) on hydriding/dehydriding properties of magnesium

Cited by 20 publications

References 20 publications

In operando study of TiVCr additive in MgH2 composites

In operando study of TiVCr additive in MgH2 composites

Catalytic influence of Ni-based additives on the dehydrogenation properties of ball milled MgH₂

Agile Thermal Management STT-RX, Modified Magnesium Hydride and Calcium Borohydride for High-Capacity Thermal Energy Storage (PREPRINT)

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Kinetic investigation of the catalytic effect of a body centered cubic-alloy TiV1.1Mn0.9 (BCC) on hydriding/dehydriding properties of magnesium

Cited by 20 publications

References 20 publications

In operando study of TiVCr additive in MgH2 composites

In operando study of TiVCr additive in MgH2 composites

Catalytic influence of Ni-based additives on the dehydrogenation properties of ball milled MgH2

Agile Thermal Management STT-RX, Modified Magnesium Hydride and Calcium Borohydride for High-Capacity Thermal Energy Storage (PREPRINT)

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Catalytic influence of Ni-based additives on the dehydrogenation properties of ball milled MgH₂