Insight into the kinetic mechanism of the first-step dehydrogenation of Mg(AlH₄)₂

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• 作者：Yuepeng Pang^a ; Qian Li^a ; ^b ; ^{shuliqian@shu.edu.cn} ; ^{shuliqian75@gmail.com}
• 关键词：Phase transformation kinetics ; Modeling ; Hydrides ; Hydrogen storage ; Reaction mechanism
• 刊名：Scripta Materialia
• 出版年：2017
• 出版时间：15 March 2017
• 年：2017
• 卷：130
• 期：Complete
• 页码：223-228
• 全文大小：1314 K
• 卷排序：130

文摘

The detailed mechanism of the first-step dehydrogenation of Mg(AlH4)2 is investigated by using a comprehensive kinetic analysis. The reaction mode (geometrical contraction or nucleation-growth-impingement), intrinsic rate constant, dimensionality, rate-controlling step and activation energies of nucleation and growth are obtained from the simultaneous fitting of isothermal and non-isothermal experimental curves. The interpretation and comparison of these kinetic parameters for the pristine, high-energy ball milled and TiF4 doped Mg(AlH4)2 help reveal the mechanism of the dehydrogenation of Mg(AlH4)2, including how Mg(AlH4)2 decomposes to MgH2, Al and H2, and why high-energy ball milling and TiF4 doping can significantly improve the dehydrogenation properties.