Thermal and Spectroscopic (IR, NMR) Studies of Ammonia Borane-Polyethylene Oxide Hydrogen Storage Composites: Effect of Catalyst

Ammonia Borane (NH₃BH₃, AB) has been a potential candidate for chemical hydrogen storage due to its high hydrogen content (19.6 wt%). A downfall to the applicability of AB is its slow dehydrogenation kinetics and production of unwanted byproducts/gases. Studies show that introduction of a polymer, such as polyvinylpyrrolidone and polyacrylamide, can improve the performance of AB and decrease the release of harmful byproducts. Furthermore, catalytic additions such as, magnesium chloride (MgCl₂) and calcium chloride (CaCl₂), have proven to lower the activation energy (E_a), improve kinetics, and lower the hydrogen release temperature. This study explores thermal and vibrational analysis of pristine AB blended with polyethylene oxide (PEO) and individual additions of MgCl₂ and CaCl₂ as catalysts. Dehydrogenation kinetics were studied using a differential scanning calorimeter and the data was then compared with AB, bulk composites and analyzed. The results with CaCl₂ catalyst and high PEO content exhibited the most improved properties (i.e. lower E_a). In addition, evidence of the interactions between AB:PEO:Catalyst were given by Fourier-transform infrared and nuclear magnetic resonance spectroscopy.