Hydrogen Storage Properties of Ca(BH4)2–LiNH2 System

Chu, Hailiang; Xiong, Zhitao; Wu, Guotao; Guo, Jianping; Zheng, Xueli; He, Teng; Wu, Chengzhang; Chen, Ping

doi:10.1002/asia.200900677

Cited by 34 publications

(30 citation statements)

References 42 publications

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“…Once E a and A are known, the specific rate constant k at given temperature can be determined by the Arrhenius equation k ¼ A expð À E a =RTÞ ð 4Þ Table 2 summarizes E a , A, and k (at 300°C) for each sample. As mentioned above, the rate constant k at 300°C of 32 suggesting a considerable enhancement in dehydrogenation kinetics of pristine Ca(BH 4 ) 2 after being combined with alkaline-earth metal amides. Because Ca-(BH 4 ) 2 À2Mg(NH 2 ) 2 sample has higher activation energy (E a = 132.7 kJ/mol) and slower rate (k = 1.2 Â 10 À2 min À1 ) for hydrogen desorption, the effect of additives as shown in Figure 8 is investigated.…”

Section: Resultsmentioning

confidence: 69%

Improved Dehydrogenation Properties of Calcium Borohydride Combined with Alkaline-Earth Metal Amides

Chu

Zhang

et al. 2011

J. Phys. Chem. C

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Promotion of dehydrogenation based on the interaction of [BH4]− and [NH2]− sources has been demonstrated to be one of the most effective approaches in developing an advanced borohydride/amide hydrogen storage combined system. The Ca(BH4)2–2Mg(NH2)2 and Ca(BH4)2–2Ca(NH2)2 composites are thereby synthesized in the present work. It is found that the binary combined systems exhibit an onset dehydrogenation temperature of ∼220 °C, which is ∼100 °C lower than that of pristine Ca(BH4)2. The hydrogen release measurements for Ca(BH4)2–2Mg(NH2)2 and Ca(BH4)2–2Ca(NH2)2 samples below 480 °C show desorption amounts of 8.3 and 6.8 wt % hydrogen, respectively. The dehydrogenation of both samples is accompanied by an ammonia emission of <1.4 mol %. The characterizations such as X-ray diffraction and nuclear magnetic resonance on the postdehydrogenated samples indicate that the dehydrogenation reactions are in the pathways of Ca(BH4)2 + 2 Mg(NH2)2 → 1/3 [Ca3Mg6(BN2)6] + 8 H2 and Ca(BH4)2 + 2 Ca(NH2)2 → 1/3 Ca9(BN2)6 + 8 H2, respectively. Compared with pristine Ca(BH4)2 sample, both possess lower activation energy for dehydrogenation. Further investigation reveals that the interaction of B–H and N–H may be one of main driving forces for dehydrogenation of borohydride/amide combined system.

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Section: Resultsmentioning

confidence: 69%

Improved Dehydrogenation Properties of Calcium Borohydride Combined with Alkaline-Earth Metal Amides

Chu

Zhang

et al. 2011

J. Phys. Chem. C

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“…Approximately 7.5 wt% of H 2 was released from Li 4 BN 3 H 10 at 160-260°C with the addition of 11 wt% of NiCl 2 [21]. Co-based additives were also found to have a catalytic effect on the hydrogen release from boron-containing hydrogen storage materials [22,23] …”

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confidence: 92%

Improved hydrogen desorption properties of Co-doped Li2BNH6

Zheng

et al. 2011

Chin. Sci. Bull.

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The hydrogen desorption properties of Li 2 BNH 6 were improved by doping with cobalt. With the addition of CoCl 2 (7 wt%), more than 8 wt% of hydrogen was released from Li 2 BNH 6 at temperatures below 210°C, which is approximately 90°C lower than that of pristine Li 2 BNH 6 . X-ray diffraction, Fourier transform-infrared and Raman characterizations revealed that the dehydrogenation was a stepwise process with the formation of intermediates Li 4 BN 3 H 10 and LiBH 4 and final products of Li 3 BN 2 and LiH. The introduction of Co greatly accelerated the dehydrogenation of Li 4 BN 3 H 10 . X-ray absorption near-edge structure measurements revealed that Co and CoB species formed during ball milling of CoCl 2 with LiBH 4 and LiNH 2 , which may function as catalyst in the subsequent dehydrogenation.

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“…[1,2] Secure storagea nd effective release of hydrogen presents evere technical challenges in the applicationo fahydrogen economy. [2][3][4][5] Consequently,m uch attention has been given to the search for materials that possessh igh gravimetric and volumetric storage capacities as well as being suitable for both portable and stationary applications of hydrogen supply. [6] At present,n umerous chemical hydrogen storage materials have been studied, including sorbentm aterials, metal hydrides, and chemical hydride systems.…”

Section: Introductionmentioning

confidence: 99%

“…Hydrogen is regarded as a globally accepted clean energy because its energy density is higher than that of petroleum and its combustion produces only water as a byproduct . Secure storage and effective release of hydrogen present severe technical challenges in the application of a hydrogen economy . Consequently, much attention has been given to the search for materials that possess high gravimetric and volumetric storage capacities as well as being suitable for both portable and stationary applications of hydrogen supply .…”

Section: Introductionmentioning

confidence: 99%

Nanoporous PtRu Alloys with Unique Catalytic Activity toward Hydrolytic Dehydrogenation of Ammonia Borane

Zhou

2016

Chemistry An Asian Journal

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Nanoporous (NP) PtRu alloys with three different bimetallic components were straightforwardly fabricated by dealloying PtRuAl ternary alloys in hydrochloric acid. Selective etching of aluminum from source alloys generates bicontinuous network nanostructures with uniform size and structure. The as-made NP-PtRu alloys exhibit superior catalytic activity toward the hydrolytic dehydrogenation of ammonia borane (AB) than pure NP-Pt and NP-Ru owing to alloying platinum with ruthenium. The NP-Pt70 Ru30 alloy exhibits much higher specific activity toward hydrolytic dehydrogenation of AB than NP-Pt30 Ru70 and NP-Pt50 Ru50 . The hydrolysis activation energy of NP-Pt70 Ru30 was estimated to be about 38.9 kJ mol(-1) , which was lower than most of the reported activation energy values in the literature. In addition, recycling tests show that the NP-Pt70 Ru30 is still highly active in the hydrolysis of AB even after five runs, which indicates that NP-PtRu alloy accompanied by the network nanoarchitecture is beneficial to improve structural stability toward the dehydrogenation of AB.

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Hydrogen Storage Properties of Ca(BH₄)₂–LiNH₂ System

Cited by 34 publications

References 42 publications

Improved Dehydrogenation Properties of Calcium Borohydride Combined with Alkaline-Earth Metal Amides

Improved Dehydrogenation Properties of Calcium Borohydride Combined with Alkaline-Earth Metal Amides

Improved hydrogen desorption properties of Co-doped Li2BNH6

Nanoporous PtRu Alloys with Unique Catalytic Activity toward Hydrolytic Dehydrogenation of Ammonia Borane

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