Understanding from First-Principles Why LiNH2BH3 · NH3BH3 Shows Improved Dehydrogenation over LiNH2BH3 and NH3BH3
2010 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 44, 19089-19095 p.Article in journal (Refereed) Published
Lithium amidoborane-ammonia borane (LiNH2BH3 center dot NH3BH3, LiAB center dot AB for short) was synthesized recently. Compared with lithium amidoborane (LiNH2BH3, LiAB for short) and ammonia borane (NH3BH3, AB for short), this new ammonia borane derivative has better dehydrogenation kinetics and releases 14.8 wt % hydrogen with peak temperatures at ca. 80 and 140 degrees C, respectively. In this report, first-principles calculations were employed to reveal the differences in dehydrogenation properties of AB, LiAB, and LiAB center dot AB. Furthermore, we attempted to correlate the crystal structure and electronic properties with dehydrogenation performance. The results show that Li+ cations play similar roles in LiAB center dot AB as in LiAB in destabilizing the B-H and N-H bonds, and the mechanism of the first-step dehydrogenation of LiAB center dot AB is likely via the dissociation and combination of hydridic H delta-(B) from LiAB molecule and protonic H delta+(N) from the adjacent AB molecule, rather than from the [LiAB] or [AB] layer alone, resulting in the desorption of H-2 at lower temperatures.
Place, publisher, year, edition, pages
2010. Vol. 114, no 44, 19089-19095 p.
IdentifiersURN: urn:nbn:se:uu:diva-135349DOI: 10.1021/jp103708zISI: 000283703500045OAI: oai:DiVA.org:uu-135349DiVA: diva2:375309