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

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.