Pressure Strategy To Improve H Atomic Utilization via Optimized Decomposition Pathway in Solid Hydrazine Borane.

ABSTRACT

Hydrazine borane (N2H4BH3, HB), a typical B-N-H compound with very high hydrogen content (15.4 wt %), is regarded as an efficient hydrogen storage material. However, during the pyrolysis at ambient pressure, solid HB decomposes, losing ∼30 wt %, which is rationalized by the evolution of hydrazine (N2H4). Here, high pressure is introduced as an analogous catalyst role that enable to optimize the decomposition pathway of solid HB. This approach improves the H atomic utilization to over 95%. Energy-dispersive spectroscopy (EDS) analysis indicates that pressure inhibits the production of N2H4, in-situ high-pressure-high-temperature Raman and in-situ high-pressure Infrared (IR) spectra, Density functional theory (DFT) calculation, and Hirshfeld analysis reveal that this inhibition is a consequence of pressure-enhanced dihydrogen and BN bonds. The superior hydrogen release properties of HB under high pressure make it a candidate for use in the synthesis of superconductor CeH9 as a hydrogen source.