CO₂-Enhanced Thermolytic H₂ Release from Ammonia Borane

Abstract

This work presents the accelerated dehydrogenation of ammonia borane (AB) at 85 °C under carbon dioxide atmosphere. The presence of CO2 significantly enhances the thermolysis kinetics, and the hydrogen release becomes faster as the CO2 pressure increases from 1.70 to 3.67 bar. Around 4 bar of CO2, 1.33 equiv of hydrogen is released from AB in 1 h. The accelerated AB thermolysis is due to CO2 reacting with AB, or intermediates like diammoniate of diborane (DADB), or primary thermolysis products including linear dimers of aminoborane (LDAB), which accelerates AB thermolysis, and this reaction has been confirmed by ATR-FTIR, Raman, and 11B and 13C solid-state MAS NMR measurements.