About the Technological Readiness of the H₂ Generation by Hydrolysis of B(−N)−H Compounds

Abstract

At the beginning of the new millennium, hydrolysis of sodium borohydride (NaBH4) was presented as a promising on‐board technology to generate H2 for light‐duty vehicles. Years later, other B(−N)−H compounds (e.g., lithium borohydride (LiBH4) and ammonia borane (NH3BH3)) emerged as attractive alternatives whereas NaBH4 was struggling with several issues jeopardizing its implementation. Actually, efforts in the research and development of H2 generation by hydrolysis of B(−N)−H compounds have been intensive since the advent of NaBH4 almost 20 years ago. There may be a question with respect to this: What is the technological readiness of the promising hydrolytic B(−N)−H compounds? This Review aims at providing relevant elements in response to this question. In the first part, the most mature B(−N)−H compounds are discussed at length. In the second part, a survey of all other candidates is proposed. It is concluded that NaBH4 is the best hydrolytic B(−N)−H compound for marketing on a broad scale, but there are still key challenges to address.

Discovery of a self-healing catalyst for the hydrolytic dehydrogenation of ammonia borane

“…8,9 While most B-N based compounds such as hydrazine borane (N2H4BH3) or metal borohydrides such as sodium borohydride (NaBH4) and lithium borohydride (LiBH4) suffer from self-hydrolysis in water, AB, being the simplest B-N compound, has a high H2 content (19.5 wt%), low molecular weight (30.9 g mol - 1 ), non-toxic nature, and particularly high stability in both aqueous solutions and air. 10 Therefore, AB has a great potential for practical on-board applications in transportation. The release of H2 from AB can be achieved either from thermolysis or solvolysis; the latter can be further classified into hydrolysis and methanolysis, in which the dehydrogenation reaction occurs in water or methanol, respectively.…”

Boron Nitride for Hydrogen Storage

“…However, the storage capacities of sorbents at ambient conditions are very low. In contrast, with borohydrides and boranes, which are H carriers, hydrogen storage and release may be effective at 20–100 °C, because of stronger binding energies than adsorption . This is what is called chemical H storage.…”

“…For instance, with the MOF denoted MOF-5(i.e.,Zn 4 O(BDC) 3 with BDC as 1,4-benzenedicarboxylate), ac ubic 3D structure displaying as pecific surfacea rea of about 3800 m 2 g À1 ,i tw as reported that an adsorptiono f7 .1 wt %H 2 (i.e.,7 1g H2 kg MOF À1 )c ould be achieved at À196 8Ca nd 40 bars H 2 . [11] However,t he storage capacities of sorbents at ambient conditions are very low.I nc ontrast, with borohydrides andb oranes, whicha re Hc arriers, hydrogen storagea nd release may be effective at 20-100 8C, [12] because of stronger binding energiest han adsorption. [9] This is what is called chemical Hs torage.…”

Hydrogen release mechanism and performance of ammonia borane catalyzed by transition metal catalysts Cu-Co/MgO(100)

“…So far, chemical hydrides are the most promising approaches for hydrogen storage since their high gravimetric capacity. Among the chemical hydrides, NH 3 BH 3 due to its high gravimetric capacity of 196 g H 2 /kg, superior regeneration performance, portable, and easy to store when not in use has become one of the most preferable hydrogen storage medium …”

“…Among the chemical hydrides, NH 3 BH 3 due to its high gravimetric capacity of 196 g H 2 /kg, superior regeneration performance, portable, and easy to store when not in use has become one of the most preferable hydrogen storage medium. [7][8][9] Hydrogen can be acquired from AB dehydrogenation by means of thermolysis or hydrolysis or in other organic solvents (eg, alcoholysis). Solid AB and aqueous AB solution reported hydrogen release by temperatures of 500 and 393 K, respectively.…”