Chemical hydrogen storage in nano-structured materials. Control of hydrogen release and reactivity from ammonia borane complexes

The DOE has issued a grand Challenge in hydrogen storage to compliment existing programs on hydrogen production and fuel cell development. In response to this challenge, a program that uses a combination of experimental and computational approaches was initiated to study the potential of NH_xBH_x (x = 1-4) as chemical hydrogen storage materials for on-board hydrogen storage. The experimental efforts on ammonia-borane [NH₃BH₃] (AB) were presented. The nanometer diameter pores of mesoporous templates were used to control the selectivity of the hydrogen release pathways from AB and polyammonia-borane. When the AB was coated on the inside of the mesoporous silica template, the template would minimize borazine formation by controlling linear polymer growth and minimizing cyclization.