Comparative Study of Structural Changes in NH3BH3, LiNH2BH3, and KNH2BH3 During Dehydrogenation Process

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• 作者：Keiji Shimoda ; Koichi Doi ; Tessui Nakagawa ; Yu Zhang ; Hiroki Miyaoka ; Takayuki Ichikawa ; Masataka Tansho ; Tadashi Shimizu ; Anthony K. Burrell ; Yoshitsugu Kojima
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：March 8, 2012
• 年：2012
• 卷：116
• 期：9
• 页码：5957-5964
• 全文大小：487K
• 年卷期：v.116,no.9(March 8, 2012)
• ISSN：1932-7455

文摘

The thermal decomposition pathways of ammonia borane (AB, NH₃BH₃), lithium amidoborane (LiAB, LiNH₂BH₃), and potassium amidoborane (KAB, KNH₂BH₃) have been investigated in detail by using solid state ¹¹B MAS NMR spectroscopy. During the first decomposition process of AB, the complex structural entities were observed, which have been attributed to polyaminoborane (PAB, (NH₂BH₂)_n). On the other hand, polyiminoborane (PIB, (NHBH)_n) formed in the second process showed a single 3-fold coordination ^IIIB signal above 125 掳C, suggesting a [鈥擝鈺怤鈥擼_n network structure. LiAB and KAB did not show the PAB-like structure, and the PIB-like structure was directly formed by the hydrogen desorption. Quantitative analyses of the ¹¹B NMR spectra suggested that the general route of the thermal decomposition of alkali metal amidoboranes (LiAB, NaAB, and KAB) is similar. Also, ³⁹K MAS NMR spectra of KAB and its decomposition products indicated the formation of KH and an amorphous K鈥揘鈥揃鈥揌 phase during the hydrogen release.