Dissociation and hydrolysis of ammonia-borane with solid acids and carbon dioxide: An efficient hydrogen generation system

Chandra, Manish; Xu, Qiang

doi:10.1016/j.jpowsour.2005.12.033

Cited by 244 publications

(128 citation statements)

References 29 publications

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“…Addition of selected transition metal catalysts, [5][6][7][8][9] acid [10,11] or ionic liquids [12] was found to greatly promote the hydrogen release from the solvolysis reactions of AB under mild conditions. Confinement of AB in nanoporous materials [13][14][15] or ploy(methyl acrylate) (PMA) [16] has proven to be an effective approach for enhancing the hydrogen release kinetics and for suppressing the volatile by-products.…”

Section: Introductionmentioning

confidence: 99%

Renewed Insight into the Promoting Mechanism of Magnesium Hydride on Ammonia Borane

Luo¹,

Kang²,

Wang³

2010

ChemPhysChem

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Our previous study found that mechanically milling with magnesium hydride (MgH(2)) could dramatically improve the dehydrogenation property of ammonia borane (AB). Meanwhile, it appears that the MgH(2) additive maintains its phase stability in the milling and subsequent heating process. In an effort to further the mechanistic understanding of the AB/MgH(2) system, we reinvestigated the property and structure evolution in the hydrogen release process of the AB/0.5MgH(2) sample. Property examination using volumetric method and synchronous thermal analyses showed that the AB/0.5 MgH(2) sample releases approximately 13.8 wt % hydrogen after being heated at 300 degrees C. This hydrogen amount is in excess of that available from AB, indicative of the participation of a faction of MgH(2) in the dehydrogenation process of AB. Structural and chemical state analyses using Fourier transformation infrared spectroscopy and solid-state (11)B nuclear magnetic resonance techniques further showed that part of MgH(2) participates in the dehydrogenation process of AB from the first step, resulting in the formation of Mg-B-N-H intermediate species. The incorporation of Mg in AB is believed to be a crucial event leading to dehydrogenation property improvements, particularly for the release of the last equivalent of H(2) in AB at relatively moderate temperature. These findings have provided renewed insight into the promoting mechanism of MgH(2) on the hydrogen release from AB.

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Section: Introductionmentioning

confidence: 99%

Renewed Insight into the Promoting Mechanism of Magnesium Hydride on Ammonia Borane

Luo¹,

Kang²,

Wang³

2010

ChemPhysChem

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“…As the theoretical H 2 /NH 3 BH 3 molar ratio was 3.0, the reaction is almost completed in the presence of the homogeneous hollow spheres prepared using 40 g of the PS suspension. Hollow silica-zirconia composite spheres [17], hollow silica-alumina composite spheres prepared using aluminum-sec-butoxide [18], and H-BEA zeolites [13] were evaluated for the hydrolytic dehydrogenation of NH 3 BH 3 as previously reported. The volumes of hydrogen evolved per gram of the hollow spheres were measured for the homogenous hollow spheres prepared using 40 g of the PS suspension, the hollow silicazirconia composite spheres, the hollow silica-alumina composite spheres prepared using aluminum-sec-butoxide, and the H-BEA zeolites, and the evolved hydrogen volumes were found to be 6.5, 2.7, 3.8, and 4.7 mL/g, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Additionally, NH 3 BH 3 releases hydrogen via a hydrolysis reaction in the presence of suitable acids and catalysts at room temperature (Eq. (1)) [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]: NH 3 BH 3 + 2H 2 O → NH 4 + + BO 2  + 3H 2 (1) It has been reported that solid acids such as H-type zeolites (H-BEA and H-MOR) show high activity for the hydrolytic dehydrogenation of NH 3 BH 3 [13]. We have reported that hollow silica-alumina composite spheres show higher activity compared with fine particles [14].…”

Section: Introductionmentioning

confidence: 99%

Influence of morphology of hollow silica–alumina composite spheres on their activity for hydrolytic dehydrogenation of ammonia borane

et al. 2017

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Hollow silica-alumina composite spheres were prepared by a polystyrene (PS) template method using various amounts of PS suspension. Homogeneous hollow spheres prepared using 40 g were found to be with a diameter of about 300 nm in scanning electron microscopy, and transmission electron microscopy demonstrated their hollow sphere morphology. From the nitrogen adsorption isotherm results, the homogeneous hollow spheres prepared using 40 g of the PS suspension were found to be an ordered pore structure. The activities of the hollow spheres prepared using various amounts of the PS suspension for hydrolytic dehydrogenation of ammonia borane were compared. The results showed that 10, 7, and 6 mL of hydrogen were evolved from the aqueous ammonia borane solution in about 40 min in the presence of the hollow spheres prepared using 40, 80, and 120 g of PS suspension, respectively. The homogeneous hollow spheres with an ordered pore structure showed the highest activity among all the hollow spheres. The amount of acid sites and the coordination number of aluminum active species were characterized using neutralization titration and solid-state 27 Al magic angle spinning nuclear magnetic resonance spectroscopy. The homogeneous hollow spheres with an ordered pore structure had high amount of acid sites and 4-coordinated aluminum species. The relative proportion of 4-coordinated aluminum species was related to the dispersion of aluminum species. These results indicate that the homogeneous hollow spheres with an ordered pore structure showed the high activity because of high amount of acid sites induced by the highly dispersed aluminum species.

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“…One of the most critical issues in the development of clean, hydrogen-based energy sources is the storage and release of hydrogen under ambient conditions hydrolysis of NH3BH3 7) . However, there are few reports about solid acids, and the relationship between the activity and the structural properties such as material size and pore size has not been fully elucidated.…”

Section: Introductionmentioning

confidence: 99%

Control of Particle Size of Hollow Silica-alumina Composite Spheres and Their Activity for Hydrolytic Dehydrogenation of Ammonia Borane

Toyama

Umegaki

et al. 2014

J. Jpn. Inst. Energy

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The influence of particle size of hollow silica-alumina composite spheres on their activity for hydrolytic dehydrogenation of ammonia borane (NH3BH3) was investigated. A silica-alumina composite shell was coated onto polystyrene (PS) template particles, before the removal of PS template particle by calcination. The diameter of the PS template particles decreased with an increase in the amount of poly (vinyl pyrrolidone) and the centrifugation speed, and the diameter of the obtained PS template particles was controlled between 150 and 400 nm. Hollow silica-alumina composite spheres with diameters of 180, 230, and 430 nm were prepared using these PS template particles; the shell thickness was controlled 15 nm by adjusting the amount of PS suspension and coating time. The hydrolytic dehydrogenation of NH 3BH3 evolved 9.5, 9.0, and 7.0 mL hydrogen in the presence of hollow spheres with diameters of 180, 230, and 430 nm, respectively; the molar ratios of the generated hydrogen to the initial NH3BH3 in the presence of the hollow spheres were 2.5, 2.3, and 1.8, respectively. The results indicate that the activity increases with a decrease in the diameter of hollow spheres.

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Dissociation and hydrolysis of ammonia-borane with solid acids and carbon dioxide: An efficient hydrogen generation system

Cited by 244 publications

References 29 publications

Renewed Insight into the Promoting Mechanism of Magnesium Hydride on Ammonia Borane

Renewed Insight into the Promoting Mechanism of Magnesium Hydride on Ammonia Borane

Influence of morphology of hollow silica–alumina composite spheres on their activity for hydrolytic dehydrogenation of ammonia borane

Control of Particle Size of Hollow Silica-alumina Composite Spheres and Their Activity for Hydrolytic Dehydrogenation of Ammonia Borane

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