Hydrogen generation from noncatalytic hydrothermolysis of ammonia borane for vehicle applications

Abstract

in Wiley Online Library (wileyonlinelibrary.com).Ammonia borane (AB) is a promising hydrogen storage material as it contains 19.6 wt % hydrogen. In this article, our recently developed hydrothermolysis approach to release hydrogen is studied over a wide range of AB concentrations (6-88 wt %), at pressure 14.7 and 200 psia, and temperature 85-135 C. It is shown that with increasing AB concentration up to 77 wt %, the H 2 yield increases, and that the role of thermolysis, when compared with hydrolysis, increases. The maximum hydrogen storage capacity, obtained at 77 wt % AB and T reactor $ 85 C along with rapid kinetics, was 11.6 and 14.3 wt % at pressure 14.7 and 200 psia, respectively. To our knowledge, on a material basis, the AB hydrothermolysis process is the first one to provide such high hydrogen yield values at near PEM fuel cell operating temperatures without use of catalyst, and thus is promising for use in fuel cell-based vehicle applications.

Nano-nickel catalytic dehydrogenation of ammonia borane

“…Above 500°C, AB can be completely decomposed to form boron nitride (BN). The residue BN is not preferred for regeneration due to high chemical and thermal stability and hence ammonia borane is treated as a disposable source [7]. The main hurdle in hydrogen release is the slow kinetics at lower temperatures leading to long induction period [8,9].…”

Hydrolysis of Ammonia Borane as a Hydrogen Source: Fundamental Issues and Potential Solutions Towards Implementation

“…A significant amount of NH 3 was released and the wt % of AB, the pressure, and the heating rate had substantial influences on NH 3 liberation. [70] For example, an increase of the NH 3 content from 6 to 9.9 mol % was observed when AB was increased from 40 to 50 wt %, whereas a further increase in the AB content resulted in a decreased NH 3 content. This was rationalized by considering NH 3 as one of the products of hydrolysis; hence, its formation is more favorable when the H 2 O content is high.…”

“…One of the drawbacks associated with the hydrolysis of AB is the generation of NH 3 , [24,59,69,70] which is detrimental for fuel cell applications. For example, Demirci and co-workers have reported that the characteristic pungent odor of NH 3 (average odor threshold of 35 mg m À3 or ca.…”

Fuel Cell Engineering: Toward the Design of Efficient Electrochemical Power Plants

“…368 Recently, novel highly asymmetric YSZ hollow fibers were prepared via a combined phase inversion and sintering method. 369 As shown by Kanakwa et al, 370 these YSZ hollow fibers have the potential to provide an attractive structure for nickel/yttria-stabilized zirconia/lanthanum strontium manganite (Ni/YSZ/LSM) electrolyte-supported microtubular SOFCs, because of the reduced thickness of the gas-tight dense electrolyte layer and increased inner surface area, while maintaining good mechanical properties.…”