Dehydrogenation mechanism of monoammoniated lithium amidoborane [Li(NH 3)NH 2BH 3]

Abstract

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 % H 2 uptake with an altogether capacity of 12 wt % dehydrogenation. Whereas the first dehydrogenation is a direct interaction between lithium amidoborane and NH 3 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 nanoclusters of [Li(NH 2)NH 2BH 3] n. © 2012 American Chemical Society.