Nanoconfined ammonia borane in a flexible metal–organic framework Fe–MIL-53: clean hydrogen release with fast kinetics

Abstract

We demonstrated the dehydrogenation behaviour of nanoconfined ammonia borane (AB) in Fe-MIL-53, a flexible metal-organic framework (MOF) by solid state thermolysis. We observed clean hydrogen release with fast kinetics at reduced temperatures. 65 85 methanol and stirred for 6 hours at room temperature. The methanol was then dried under vacuum at room temperature for 24 hours to remove the excess methanol. The targeted AB:M ratio was reconfirmed by weighing the initial MIL and AB-MIL after complete vacuum drying process. Samples with 0.5:1, 1:1, 90 and 1.5:1 molar ratios of AB:Fe were prepared. Samples without AB were also prepared in the same way and labelled as 'control'

Robust 3D Boron Nitride Nanoscaffolds for Remarkable Hydrogen Storage Capacity from Ammonia Borane

“…[14] Nanosizing is expected to result in altered atomic charges of the NH 3 BH 3 molecules and/or ap erturbed intermolecular N-H d + ··· Àd H-B network and, accordingly,k inetic effects may also explain the aforementioned shift. [8,17,19,64] No endothermic meltingp eak is observed;t his is indicative of the occurrence of ad irect solidstate decomposition. TheT Ga nd the MS results may be further exploited to estimate the storage capacity of confined AB.T aking into accountt he weight losses measureda t8 0 and 100 8Ca nd considering only the quantity of AB confined in the BN samples (196 mg in the mBN1000 samplea nd 192 mg in the mBN1450 sample), one can suggest an effective gravimetric hydrogen storage capacity of 6.9 (AB@mBN1000)a nd 3.7 (AB@mBN1450)w t% at 80 8Ca nd 8.1 (AB@mBN1000)a nd 7.3 (AB@mBN1450)w t% at 100 8C.…”

“…[13] Since this pioneering work, variousn anoscaffolds have been reported and are mainly based on carbon and silica. [14][15][16][17][18][19][20][21][22] Thed estabilization of AB is generally explained by two phenomena. Thef irst is the nanosizing of the hydride particles;t his results in defects ites that initiate the dehydropolymerizationo fA Ba tl ower temperatures.…”

Organometallics and Related Molecules for Energy Conversion

“…Recently, Srinivas, Yildirim, and coworkers loaded AB to another flexible Fe-MIL-53 framework (MIL: Material of the Institut Lavoisier, [Fe III (OH) (BDC)], BDC ¼ 1,4-benzenedicarboxylate) [139,140] with coordinatively saturated Fe sites with AB:Fe molar ratios of 0.5:1, 1:1, and 1.5:1 [141]. The encapsulation of AB in Fe-MIL-53 exhibits fast hydrogen release of 1.38 equiv.…”

The Recycling of Spent Ammonia Borane with HBr/AlBr3 and Other HX/AlX3‐Based Schemes

“…Because of the low hydrogen release temperatures and the wide range of dehydrogenation possibilities, the compound has been studied extensively in recent years . Most research in this context has been devoted to the hydrogen release kinetics of AB in different phases . The hydrogen release from AB is accompanied by a heat release caused by the formation of strong B−N bonds leading to borazine or polymerized BNH x ‐waste products like polyaminoborane and heavily cross‐linked polyborazylene (PB).…”