Dehydrogenation Mechanism of Monoammoniated Lithium Amidoborane [Li(NH3)NH2BH3]

摘要

Monoammoniated lithium amidoborane has been experimentally synthesized. When this is heated to a temperature of 40—55 °C, this releases 9—11 wt % hydrogen. First-principles density functional calculations have been carried out to understand the underlying mechanism of dehydrogenation. Theoretical results predict that the reaction is a three-step process; each step consists of 3.7, 3.9, and 4.0 wt % H2 uptake with an altogether capacity of 12 wt % dehydrogenation. Whereas the first dehydrogenation is a direct interaction between lithium amidoborane and NH3 monomers, the subsequent reaction steps lead to further dehydrogenation, provided that the activation barrier falls within reasonable limits, and this has been achieved by forming higher-order nanodusters of [Li(NH2)-NH2BH3]_n.