Synthesis of Ammonia Borane Nanoparticles and the Diammoniate of Diborane by Direct Combination of Diborane and Ammonia

Pure nanoparticle ammonia borane (NH3 BH3 , AB) was first prepared through a solvent-free, ambient-temperature gas-phase combination of B2 H6 with NH3 . The prepared AB nanoparticle exhibits improved dehydrogenation behavior giving 13.6 wt. % H2 at the temperature range of 80-175 °C without severe foaming. Ammonia diborane (NH3 BH2 (μ-H)BH3 , AaDB) is proposed as the intermediate in the reaction of B2 H6 with NH3 based on theoretical studies. This method can also be used to prepare pure diammoniate of diborane ([H2 B(NH3 )2 ][BH4 ], DADB) by adjusting the ratio and concentration of B2 H6 to NH3 .