Ammonia borane as hydrogen storage materials

Özkar, Saim
Ammonia borane is an appropriate solid hydrogen storage material because of its high hydrogen content of 19.6% wt., high stability under ambient conditions, nontoxicity, and high solubility in common solvents. Hydrolysis of ammonia borane appears to be the most efficient way of releasing hydrogen stored in it. Since ammonia borane is relatively stable against hydrolysis in aqueous solution, its hydrolytic dehydrogenation can be achieved at an appreciable rate only in the presence of suitable catalyst at room temperature. Metal(0) nanoparticles have high initial catalytic activity in releasing H-2 from ammonia borane. Thermodynamically instable metal(0) nanoparticles can kinetically be stabilized against agglomeration either by using ligands in solution or by supporting on the surface of solid materials with large surface area in solid state. Examples of both type of stabilization are presented from our own studies. The results show that metal(0) nanoparticles dispersed in solution or supported on suitable solid materials with large surface area can catalyze the release of H-2 from ammonia borane at room temperature. Dispersion of metal(0) nano particles, stabilized in liquid phase by anions or polymers, seems advantageous as providing more active sites compared to the metal nanoparticles supported on a solid surface. However, the supported metal nanoparticles are found to be more stable against agglomeration than the ones dispersed in liquid phase. Therefore, metal nanoparticles supported on solid materials have usually longer lifetime than the ones dispersed in solution. Examples are given from the own literature to show how to improve the catalytic activity and durability of metal nanoparticles by selecting suitable stabilizer or supporting materials for certain metal. For the time being, nanoceria supported rhodium(0) nano particles are the most active catalyst providing a turnover frequency of 2010 min(-1) in releasing H-2 from ammonia borane at room temperature. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.


Transition metal nanoparticle catalysts in releasing hydrogen from the methanolysis of ammonia borane
Özkar, Saim (Elsevier BV, 2020-03-13)
Ammonia borane (H3N center dot BH3, AB) is one of the promising hydrogen storage materials due to high hydrogen storage capacity (19.6% wt), high stability in solid state as well as in solution and nontoxicity. The methanolysis of AB is an alternative way of releasing H-2 due to many advantages over the hydrolysis such as having high stability against self releasing hydrogen gas. Here we review the reports on using various noble or non-noble metal(0) catalysts for H-2 release from the methanolysis of AB. Ni...
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Boran, Asli; Erkan, Serdar; Eroğlu, İnci (Elsevier BV, 2019-07-12)
Being a boron-based compound, sodium borohydride, NaBH4, is a convenient hydrogen storage material for applications like unmanned air vehicles. There are several concerns behind commercialization of hydrogen gas generator by NaBH4 hydrolysis systems. This study aims to contribute to the solution of the problems of NaBH4 hydrolysis system in three main ways. First, the usage of solid state NaBH4 enables to increase the durability and the gravimetric H-2 storage capacity of the system in order to meet US DOE ...
Poly(4-styrenesulfonic acid-co-maleic acid) stabilized nickel(0) nanoparticles: Highly active and cost effective catalyst in hydrogen generation from the hydrolysis of hydrazine borane
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When hydrazine borane is added to the solution of nickel(II) chloride and poly(4-styrenesulfonic acid-co-maleic acid), PSSMA, both reduction of nickel(II) ions to nickel(0) nanoparticles and hydrogen release from the hydrolysis of hydrazine borane occur concomitantly at room temperature. Using the hydrogen evolution from the hydrolysis of hydrazine borane as reporter reaction provides valuable insights to the formation kinetics of nickel(0) nanoparticles. Nickel(0) nanoparticles are in situ formed from the ...
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Hydrogen (H-2) is a promising alternative energy carrier which can be produced biologically. Rhodobacter capsulatus, a non-sulfur purple photosynthetic bacterium, can produce H-2 under nitrogen-limited, photoheterotrophic conditions by using reduced carbon sources such as simple organic acids. Outdoor closed photobioreactors; used for biological H-2 production are located under direct sunlight, as a result; bioreactors are exposed to temperature fluctuations during day time. In this study to overcome this p...
Citation Formats
S. AKBAYRAK and S. Özkar, “Ammonia borane as hydrogen storage materials,” INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, pp. 18592–18606, 2018, Accessed: 00, 2020. [Online]. Available: