The thermal decomposition of ammonia borane: A potential hydrogen storage material

Abstract One equivalent of hydrogen gas is evolved from ammonia borane (NH 3 BH 3 ) when it is heated above 70 °C. The initial stages of this process have been examined using TG/DSC, optical microscopy, and high temperature X-ray diffraction. Two exothermic events have been observed, the first of which takes place without hydrogen evolution. During this stage, the sample loses its crystallinity and birefringence. The products are believed to be a more mobile form of NH 3 BH 3 and the diammoniate of diborane ([NH 3 BH 2 NH 3 ] + [BH 4 ] − ). These products subsequently react in the second exothermic stage to generate hydrogen.