(428b) New Methods to Generate Hydrogen From Boron-Compounds for Vehicle Applications

Hydrogen-rich boron-compounds are attractive as hydrogen storage materials for vehicle applications. Among these, ammonia borane (AB, NH₃BH₃) has received considerable interest owing to its high hydrogen content (19.6 wt%), hydrogen release under moderate conditions, and stability at room temperature. We have recently proposed and demonstrated new methods to generate H₂ from AB, including hydrothermolysis and thermolysis with additives. Using these approaches, high H₂ yields (11-14 wt %) can be obtained with rapid kinetics at or near PEM fuel cell operating temperatures (80-90^oC). In addition, magnesium borohydride (MBH, Mg(BH₄)₂) is also an attractive material because of its high hydrogen content (14.9 wt%), reversibility, and moderate hydrogen release temperature. It was found that certain additives can improve the dehydrogenation properties of MBH significantly. While neat MBH starts to release hydrogen > 270^oC, MBH with a specific additive begins hydrogen release ~ 75^oC, which is below PEM fuel cell operating temperatures. Our results suggest that the proposed methods are promising for hydrogen storage, and could be used for PEM fuel cell vehicle applications.