Thermodynamic–kinetic characterization of the synthesized Mg2FeH6–MgH2 hydrides mixture
Thermodynamic–kinetic characterization of the synthesized Mg2FeH6–MgH2 hydrides mixture
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DOI：
10.1016/j.ijhydene.2007.11.030
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发表时间：
2008-07
影响因子：
7.2
通讯作者：
J. Puszkiel;P. A. Larochette;F. Gennari
中科院分区：
文献类型：
--
作者：
J. Puszkiel;P. A. Larochette;F. Gennari
氢经济的相关性日益增强，人们对寻找安全的氢气运输方式产生了兴趣。为了更好地理解Mg-Fe-H体系的行为，我们研究了一种由络合氢化物Mg_2FeH_6(49wt%)、氢化镁镁(18wt%)和未反应的镁和铁组成的材料的热力学和动力学特性。通过机械球磨2 mg-Fe元素粉末混合物，然后在673K和6 Mpa下氢化15h合成了这种材料。在573-673K温度范围内，通过压力-组成等温线(PCI值)测量，评价了镁铁氢化合物-镁氢化物混合物的热力学。绘制了van‘t Hoff图，计算了分解热和分解熵等热力学参数。对体系的动力学进行了研究，分析了吸氢速率与温度的关系，以及在一定温度下的放氢速率。
The increasing relevance of hydrogen economy has generated interest in finding a safe way to transport hydrogen. In order to contribute to a better comprehension of Mg–Fe–H system's behavior, we have examined thermodynamic and kinetic characteristics of a material originally composed of complex hydride Mg2FeH6(49wt%), magnesium hydride MgH2(18wt%) and unreacted magnesium and iron. Such material was synthesized via mechanical milling of a 2Mg–Fe elemental powder mixture with a subsequent hydriding process at 673K and 6MPa for 15h. Thermodynamics of the Mg2FeH6–MgH2hydrides mixture was evaluated by pressure–composition isotherm (PCI) measurements in the range of 573–673K. The van’t Hoff graph was plotted and the thermodynamic parameters, i.e. decomposition enthalpy and entropy, were calculated. The kinetics of the system was also studied to analyze the dependence of hydrogen absorption rate on the temperature and the rate of hydrogen release at a given temperature.