مهدی اسرافیلی دیزجی

There has been rapidly growing interest for materials suitable to store hydrogen in solid state for transportation of hydrogen that requires materials with high volumetric and gravimetric storage capacity. Among these materials, B-N compounds are well suited for this purpose due to their light weight, high gravimetric hydrogen storage capacity and so on. Hydrazine borane is one of these B-N compounds is with a gravimetric hydrogen storage capacity of 15.4% wt that can be used for the storage of hydrogen. In this study, for the first time, we studied the adsorption and dissociation of hydrazine borane (N2H4BH3, HB) over the pristine and Al-embedded boron nitride nanotube (BNNT and Al-BNNT) by means of density functional theory calculations. Our results reveal that the N2H4BH3 molecule can be easily adsorbed on the exterior surface of the BNNT and Al-BNNT with noticeable adsorption energies and charge transfers. There are three (A, B, C) and two (D, E) stable configurations for the adsorption of N2H4BH3 over the BNNT and Al-BNNT, respectively. Among them, complex A and D are the most favorable adsorption configurations over BNNT and Al-BNNT surface, respectively. However, the evaluated extremely high desorption energies of HB molecule over BNNT suggest that the HB splitting is both thermodynamically and kinetically unfavorable at room temperature. This is also happens for the decomposition of HB molecule over Al-BNNT except complex D. It is found that the adsorption and decomposition of the HB molecule is better performed over the Al-BNNT and this surface can act as an efficient metal free catalyst to decompose HB molecule.