Improvement on Hydrogen Desorption Performance of Calcium Borohydride Diammoniate Doped with Transition Metal Chlorides

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• 作者：Hailiang Chu ; Shujun Qiu ; Yongjin Zou ; Cuili Xiang ; Huanzhi Zhang ; Fen Xu ; Lixian Sun ; Huaiying Zhou
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：January 15, 2015
• 年：2015
• 卷：119
• 期：2
• 页码：913-918
• 全文大小：340K
• ISSN：1932-7455

文摘

Calcium borohydride diammoniate with a molecular formula of Ca(BH₄)₂路2NH₃ is a novel complex hydride for hydrogen storage. However, it suffers from high temperature and sluggish kinetics for hydrogen desorption. In this work, the temperature and kinetics for hydrogen desorption of calcium borohydride diammoniate were effectively improved through doping transition metal chlorides (such as CoCl₂, NiCl₂, and FeCl₃) in a closed vessel. Three additives could effectively decrease the temperature for hydrogen desorption of Ca(BH₄)₂路2NH₃. Among them, CoCl₂-doped Ca(BH₄)₂路2NH₃ could desorb hydrogen even at a low temperature of 170 掳C, and at 200 掳C, 7.6 wt % hydrogen with high purity is released, which shows superior performance for hydrogen desorption than that of pristine Ca(BH₄)₂路2NH₃. For CoCl₂-doped Ca(BH₄)₂路2NH₃, X-ray absorption fine structure (XAFS) revealed that the improvements could be ascribed to the catalytic function of well-dispersed cobalt particles, which results in a much lower activation energy (86.1 kJ/mol) for hydrogen desorption of calcium borohydride diammoniate.