Efficient hydrogen evolution from Amberlyst-15 mediated hydrolysis of ammonia borane under mild conditions

The efficient and cost-effective implementation of ammonia borane (AB) hydrolysis dehydrogenation for hydrogen storage is crucial. This study investigated the role of solid acid Amberlyst-15 (A-15) for hydrogen evolution from AB hydrolysis. Notably, AB hydrogen evolution rate can reach 194.15 ml·min⁻¹ at 30 °C, with a low apparent activation energy of 8.20 kJ·mol⁻¹. After five cycles of reuse, the reaction involving A-15 could keep a conversion rate of about 93%. The AB hydrolysis follows quasi first-order kinetics with respect to the AB concentration and quasi zero-order kinetics with respect to the A-15 mass. According to the characterization results of XRD, ATR-FTIR, and in-situ MS, the boric acid was the dominant hydrolyzate, while water as a hydrogen donor in this reaction. Furthermore, based on the reasoning that hydrogen bonds between A-15 and AB (aq) promotes the diffusion of AB, release of H₂ and the cleavage of O—H bond of H₂O, a possible mechanism was proposed.