【作者】 温玉娟；

【导师】 欧阳柳章；

【作者基本信息】 华南理工大学 ， 材料加工工程， 2010， 硕士

【摘要】 MgH2水解制氢,纯度高,无污染,但是反应过程形成的钝化层阻碍水解的进一步,使得反应难以完全进行,产率低。为了克服MgH2的这些缺点,本文对国内外水解制氢的研究进展进行综述,研究了Mg₃RE基氢化物（H-Mg₃RE）的水解性能并着重探讨了Ni、Al对Mg₃RE合金水解性能的影响。本文所用合金采用感应熔炼法制备,将制备的Mg₃RE合金、Mg₃RENi_0.1合金和Mg₃RENi_0.1Al_0.1合金进行氢化并使其饱和吸氢,然后在常温下水解;运用X射线衍射（XRD）、能谱（EDX）分析等手段,研究了加入Ni、Al后的Mg₃RE合金球磨后的微观结构,同时研究了相应的氢化过程和水解过程的反应机理;测定了H-Mg₃RE水解产氢量,并对水解动力学做了初步的分析。研究表明,Mg₃RE合金球磨后仍然保持其原来的相不变,Mg₃RENi_0.1以Mg₃RE（D03结构）为基本相,形成少量的REMg2Ni,或者少量的RE2Mg17;Mg₃RE基合金氢化后的产物都为MgH2和REH2³。Mg₃Nd氢化物（H-Mg₃Nd）水解反应不完全,有Nd2H5残余,Mg₃CeNi_0.1氢化物(H- Mg₃CeNi_0.1)水解产物为Mg（OH）2和CeO2,其余Mg₃RE氢化物的水解产物为Mg（OH）2和RE（OH）2³。Mg₃RE氢化物在常温下发生水解反应,在前5分钟,Mg₃Mm合金氢化物（H-Mg₃Mm）的水解反应速度最快,达到131ml/（g.min）,H-Mg₃Nd合金的水解反应速度最慢,只有82ml/（g.min）。H-Mg₃Mm的水解产氢量最大,达到1039ml/g。从反应机制来看,Mg₃La合金氢化物（H-Mg₃La）、Mg₃Pr合金氢化物（H-Mg₃Pr）和H-Mg₃Nd的水解反应机制为三维表面反应机制,Mg₃Ce合金氢化物（H-Mg₃Ce）和H-Mg₃Mm的水解反应机制为一维扩散反应机制,一维扩散反应机制的水解性能优于三维表面反应机制。添加Ni元素后,Mg₃RENi_0.1氢化物(H-Mg₃LaNi_0.1、H-Mg₃CeNi_0.1、H-Mg₃PrNi_0.1、H-Mg₃NdNi_0.1和H-Mg₃MmNi_0.1)在常温298K下的水解产氢量分别达到9.05 wt%,9.71 wt% ,8.52 wt%,7.49 wt%和8.48 wt%。在前5分钟,H-Mg₃MmNi_0.1合金的水解反应速度最快,H-Mg₃CeNi_0.1的最后产氢量最大。从反应机制看,Ni的加入使得H-Mg₃RENi_0.1在常温298K下的水解反应都是一维扩散反应控制机制。继续添加Al到Mg₃LaNi_0.1,Mg₃LaNi_0.1Al_0.1合金氢化物(H-Mg₃LaNi_0.1Al_0.1)水解反应前5分钟产氢速率最快,达到120 ml/g·min。而H-Mg₃LaNi_0.1的水解产氢量最高,达到1024ml/g。由于Ni和Al的加入,水解反应控制机制由H-Mg₃La的三维表面反应机制变为H-Mg₃LaNi_0.1和H-Mg₃LaNi_0.1Al_0.1合金的一维扩散反应控制机制。更多还原

【Abstract】 The characteristics of MgH2 in hydrolysis are high hydrogen purity and environment friendly. However, the passivation of Mg（OH）2 hinders the further hydrolysis and leads to the low hydrogen generation yield. To overcome these shortcomings, in this thesis, it not only focuses its attention on the hydrolysis properties of Mg₃RE （RE=La, Ce, Pr, Nd and Mm） hydrides, but also the effect of Ni and Al addition on the hydrolysis, based on the reviewing of world wide development of hydrolysis. The Mg₃RE and the Mg₃RE-based alloys prepared by induction melting were hydrogenated fully, and then hydrolyzed at room temperature. the phase structure before/after ball-milling and hydrolysis reaction agent was investigated by using X-ray diffraction（XRD） and energy dispersive X-ray spectroscopy（EDX） in order to understand the reaction mechanism during the process of hydrogenation and hydrolysis. And meanwhile, the hydrolysis processes were also tested. Based on the data of hydrolysis, the hydrolysis kinetics was also analyzed.Based on the XRD analysis, Mg₃RE alloys are composed of the D03 structure. While the phases of Mg₃RENi_0.1 alloys are are composed of Mg₃RE with D03 structure phase and small amount of REMg2Ni and/or RE2Mg17. The products of Mg₃RE based alloys after hydrogenated are MgH2 and REH2³. Except that the products of Mg₃Nd hydrides （H-Mg₃Nd） after hydrolysis are Nd2H5 and Mg（OH）2, and Mg₃CeNi_0.1 hydrides (H-Mg₃CeNi_0.1) are Mg（OH）2 and CeO2, the products of other Mg₃RE hydrides alloys after hydrolysis are Mg（OH）2and RE（OH）2³.In the first 5 min, the hydrogenated Mg₃Mm had the quickest hydrolysis rate （131ml/（g.min）） and the hydrogenated Mg₃Nd reacted with water at the slowest hydrolysis rate （82ml/（g.min））. And the highest hydrogen yield is 1039 ml/g for the hydrogenated Mg₃Mm. The hydrolysis mechanism of H-Mg₃RE was also discussed in this thesis.After introducing the Ni element into Mg₃RE alloy, the hydrogen generation capacity for Mg₃RENi_0.1 hydrides (H-Mg₃LaNi_0.1, H-Mg₃CeNi_0.1, H-Mg₃PrNi_0.1, H-Mg₃NdNi_0.1 and H-Mg₃MmNi_0.1) were up to 9.05 wt%,9.71 wt%,8.52 wt%,7.49 wt% and 8.48 wt%. In the first 5 min, H-Mg₃MmNi_0.1 had the highest hydrolysis among all these alloys.When Al was introducd into Mg₃LaNi_0.1, it could be found that Mg₃LaNi_0.1Al_0.1 hydrides (H-Mg₃LaNi_0.1Al_0.1) had the quickest hydrogen generation rate, which is up to 120 ml/g?min. this is due to the addition of Ni and Al, the hydrolysis mechanism had been changed.更多还原