Hydrolysis of Mg-salt and MgH2-salt mixtures prepared by ball milling for hydrogen production
Hydrolysis of Mg-salt and MgH2-salt mixtures prepared by ball milling for hydrogen production
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DOI：
10.1016/j.jallcom.2005.09.008
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发表时间：
2006-06-08
影响因子：
6.2
通讯作者：
Roue, Lionel
中科院分区：
文献类型：
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作者：
Grosjean, Marie-Helene;Roue, Lionel
众所周知，Mg或MgH 2与水之间的反应产生氢气。然而，由于在反应性材料上形成钝化Mg（OH）（2）层，该反应迅速停止。Mg或MgH 2与固体盐的研磨似乎非常有效地改善它们的水解反应性。研磨时间（0.5、3和10小时）、盐的量（1、3和10摩尔%）和盐组成（KCl、NaCl、LiCl和MgCl 2）都是在转化率和动力学方面控制水解反应的参数。盐添加剂在研磨时充当过程控制剂，其增加Mg粉末的比表面积（对于更脆的MgH 2粉末无效）。此外，水解过程中的盐溶解被认为破坏了Mg（OH）（2）钝化层，有利于Mg或MgH 2与水之间的反应。与盐添加剂如MgCl 2的放热溶解相关的驱动力也是加剧MgH 2和Mg水解的关键因素。0.5 h研磨的MgH 2 -3 mol% MgCl 2复合物在研磨持续时间和制氢性能方面显示出最佳的折衷，每克复合物产生964 ml的氢气。(c)2005 Elsevier B. V.保留所有权利。
It is well known that the reaction between Mg or MgH2 and water produces hydrogen. However, this reaction stops rapidly, due to the formation of a passive Mg(OH)(2) layer onto the reactive material. The milling of Mg or MgH2 with solid salts appears very effective to improve their hydrolysis reactivity. The milling time (0.5, 3 and 10h), the amount of salt (1, 3 and 10mol%) and the salt composition (KCl, NaCl, LiCl and MgCl2) are all parameters that control the hydrolysis reaction in terms of conversion yield and kinetics. The salt additive acts as a process control agent upon milling that increases the specific surface area of the Mg powder (not valid for more brittle MgH2 powder). In addition, the salt dissolution during the hydrolysis is assumed to break down the passive Mg(OH)(2) layer, favouring the reaction between Mg or MgH2 and water. The driving force related to the exothermic dissolution of the salt additive such as MgCl2 is also a key factor for accentuating the MgH2 and Mg hydrolysis. The 0.5 h milled MgH2-3 mol% MgCl2 composite displays the best compromise in terms of milling duration and hydrogen production performance with 964 ml of hydrogen produced per gram of composite. (c) 2005 Elsevier B.V. All rights reserved.