Release of Pure H2 from Na[BH3(CH3NH)BH2(CH3NH)BH3] by Introduction of Methyl Substituents

Abstract

Over the last 10 years, hydrogen-rich compounds based on five-membered boron–nitrogen chain anions have attracted attention as potential hydrogen storage candidates. In this work, we synthesized Na[BH3(CH3NH)BH2(CH3NH)BH3] through a simple mechanochemical approach. The structure of this compound, obtained through synchrotron powder X-ray diffraction, is presented here for the first time. Its hydrogen release properties were studied by thermogravimetric analysis and mass spectrometry. It is shown here that Na[BH3(CH3NH)BH2(CH3NH)BH3], on the contrary of its parent counterpart, Na[BH3NH2BH2NH2BH3], is able to release up to 4.6 wt.% of pure hydrogen below 150 °C. These results demonstrate that the introduction of a methyl group on nitrogen atom may be a good strategy to efficiently suppress the release of commonly encountered undesired gaseous by-products during the thermal dehydrogenation of B-N-H compounds.