Synthesis, structural characterization, and hydrogen desorption properties of Na[Al(NH2BH3)4]
Synthesis, structural characterization, and hydrogen desorption properties of Na[Al(NH2BH3)4]
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DOI：
10.1016/j.ijhydene.2016.12.062
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发表时间：
2017-03
影响因子：
7.2
通讯作者：
Y. Nakagawa;K. Shinzato;T. Nakagawa;Keita Nakajima;S. Isobe;Kiyotaka Goshome;H. Miyaoka;T. Ichikawa
中科院分区：
文献类型：
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作者：
Y. Nakagawa;K. Shinzato;T. Nakagawa;Keita Nakajima;S. Isobe;Kiyotaka Goshome;H. Miyaoka;T. Ichikawa
采用球磨法（固相法）和在THF中的化学反应法（溶液法）合成了混合金属氨基硼烷Na[Al（NH 2BH 3）4]。固相法有残留未反应的NaAlH 4和AB的倾向。在溶液法中，Na[Al（NH_2BH_3）_4]在THF中混合时会发生部分分解。用MAS NMR和FT-IR对材料的结构进行了表征，发现Na[Al（NH 2BH 3）4]的脱氢分两步进行，而第二步的脱氢来自Al单键N单键B单键H相。研究了球磨过程中氢压对nNH_3BH_3单键NaAlH_4（n= 1，4）复合材料的影响。当n = 4时，在Ar和H2气氛下均生成Na[Al（NH 2BH 3）4]。当n = 1时，在H2气氛下，只有Na[Al（NH 2BH 3）4]生成，而在Ar气氛下，大部分H2在球磨过程中脱附。因此，在n = 1的情况下，氢压力对于合成是必需的。描述了AB-NaAlH 4体系的势能图。
Na[Al(NH2BH3)4], a mixed-metal amidoborane, was synthesized by ball-milling (solid method) and the chemical reaction in THF (solution method). Solid method has a tendency to remain unreacted NaAlH4and AB. In the solution method, the partial decomposition of Na[Al(NH2BH3)4] would proceed during mixing in THF. The local structural characterization of as-synthesized material was performed by MAS NMR and FT-IR. While Na[Al(NH2BH3)4] desorbed hydrogen in two steps as reported, the results of structural characterization suggested that the hydrogen desorption in the 2nd step would originate from the Alsingle bondNsingle bondBsingle bondH phase. Effect of hydrogen pressure during ball-milling was also investigated fornNH3BH3single bondNaAlH4(n= 1, 4) composites. In the case ofn= 4, Na[Al(NH2BH3)4] was formed under both Ar and H2atmosphere. However, in the case ofn= 1, Na[Al(NH2BH3)4] was only formed under H2atmosphere, whereas most of H2was desorbed during ball-milling under Ar atmosphere. Thus, the hydrogen pressure is necessary for the synthesis in the case ofn= 1. Potential energy diagram of AB-NaAlH4system was described.