Hydrogen desorption properties of the Ca-N-H system
Hydrogen desorption properties of the Ca-N-H system
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DOI：
10.1016/j.jallcom.2005.01.052
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发表时间：
2005-08-02
影响因子：
6.2
通讯作者：
Fujii, H
中科院分区：
文献类型：
--
作者：
Hino, S;Ichikawa, T;Fujii, H
用氢化钙（CaH_2）与氨（NH_3）反应合成了氨化钙（Ca（NH_2）（2）），并对其热分解性能进行了研究。结果表明，随着温度的升高，Ca（NH 2）（2）分解为酰亚胺钙（CaNH）和NH3气体，其中NH3的脱附开始于约60 ℃，在热脱附质谱（TDMS）中在300 ℃左右达到峰值。从X射线衍射图可以看出，在热处理至350 ℃后的产物是CaNH，但在进一步加热至500 ℃时出现了未知相。同时考察了Ca（NH_2）_2和CaH_2摩尔比为1：3的混合物的脱氢性能。3.5wt.%的H-2气体在TDMS中，总的脱附量为双峰结构。第一个峰对应于反应：Ca（NH 2）（2）+CaH 2-> 2CaNH +2 H（2），第二个峰来自反应：CaNH + CaH 2-> Ca 2NH + H-2。同时进行的差热分析表明，前者和后者的反应，分别是放热和吸热，因此，在TDMS中的第一个峰对应的H，解吸消失后，在室温下长时间研磨。(c)2005 Elsevier B. V.保留所有权利。
After synthesizing calcium amide (Ca(NH2)(2)) through the reaction of calcium hydride (CaH2) with ammonia (NH3), the thermal decomposition properties have been examined. The results indicated that Ca(NH2)(2) decomposed to calcium imide (CaNH) and NH3 gas with increasing temperature, where the desorption of NH3 started from about 60 degrees C and peaked around 300 degrees C in the thermal desorption mass spectra (TDMS). From the X-ray diffraction profiles, the product after heat treatment up to 350 degrees C was CaNH, but an unknown phase appeared in further heating up to 500 degrees C. Hydrogen (H-2) desorption properties of a mixture of Ca(NH2)(2) and CaH2 with 1:3 molar ratio were also examined. The H-2 gas of 3.5 wt.% in total was desorbed with two-peak structure in TDMS. The first peak corresponds to the reaction: Ca(NH2)(2) + CaH2 -> 2CaNH + 2H(2), and the second one originates from the reaction: CaNH + CaH2 -> Ca2NH + H-2. Simultaneously performed differential thermal analysis indicated that the former and the latter reactions were, respectively, exothermic and endothermic, so that the H, desorption corresponding to the first peak in TDMS disappeared after long-time-milling at room temperature. (c) 2005 Elsevier B.V. All rights reserved.