Behavior of decomposed ammonia borane at high pressure

•Found loss of dihydrogen bonding after decomposition of ammonia borane•The decomposition of ammonia borane is non-reversible.•The decomposed residual of ammonia borane can store extra hydrogen under high pressure.

High pressure behavior of ammonia borane after thermal decomposition was studied by Raman spectroscopy at high pressure up to 10 GPa using diamond anvil cell (DAC). The ammonia borane was decomposed at around 140 °C under the pressure at ∼0.7 GPa. Raman spectra show the hydrogen was desorbed within 1 h. The hydrogen was sealed in DAC well and cooled down to room temperature. Applying higher pressure up to ∼10 GPa indicates interactions between the products and loss of dihydrogen bonding. No rehydrogenation was detected in the pressure range investigated.