Ammonia borane (AB) is one most attractive solid-state medium for on-board hydrogen storage because of its high hydrogen density (19.6 wt. %) and its stability at ambient conditions. The hydrogen release, however, is slow at the working temperature (~ 85 oC) of polymer electrolyte membrane fuel cell. In this work, we demonstrate that CO2-treatment can accelerate hydrogen release. After exposing AB to 1.38 MPa of carbon dioxide (CO2) at 70 oC for about 38 min, 1.5 mol H2/AB (mol) rapidly desorbs at 85 �C in 1 h, corresponding to 10.1 wt.% of H2 regarding the amount of pristine AB. Also, our results show the promoted effect can be preserved for more than four days after isolating AB. The degree of dehydrogenation is further confirmed by spectroscopic and elemental analyses of the solid product. The FTIR spectra display the N�H stretching mode involving p-bonded nitrogen (sp2 N),while the atom ratio of H:B is found to be 2.84:1. From a conflation of hydrogen release measurements, spectroscopic observations and elemental analyses, we deduce that the predominant solid product of dehydrogenation of CO2-treated AB at 85 �C is a polymer with an empirical formula of (NBH3)n.

Fast hydrogen desorption from CO<sub>2</sub>-treated ammonia borane

244th National Meeting (2012)

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Fast hydrogen desorption from CO2-treated ammonia borane

Fast hydrogen desorption from CO₂-treated ammonia borane