Catalytic effect of nanoparticle 3d-transition metals on hydrogen storage properties in magnesium hydride MgH2 prepared by mechanical milling
Catalytic effect of nanoparticle 3d-transition metals on hydrogen storage properties in magnesium hydride MgH2 prepared by mechanical milling
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DOI：
10.1021/jp044576c
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发表时间：
2005-04-21
影响因子：
3.3
通讯作者：
Fujii, H
中科院分区：
文献类型：
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作者：
Hanada, N;Ichikawa, T;Fujii, H
我们研究了纳米颗粒3d过渡金属对通过机械球磨法制备的MgH₂的氢解吸（HD）性能的催化作用。通过添加少量纳米颗粒Fe - 纳米、Co - 纳米、Ni - 纳米和Cu - 纳米金属并球磨2小时制备的所有MgH₂复合材料，都显示出比纯球磨MgH₂本身好得多的氢解吸性能。特别是，在200转/分钟的低球磨转速下软磨15分钟短时间制备的2摩尔% Ni - 纳米掺杂的MgH₂复合材料显示出最优异的储氢性能：在氦气流中（无氢气分压），以5℃/分钟的加热速率，在150℃至250℃的温度范围内解吸出大量氢气（约6.5 wt%）。与Mg和Ni元素分布相对应的能谱（EDX）显微照片表明，作为催化剂的纳米颗粒Ni金属均匀地分散在MgH₂表面。此外，已证实该产物即使在150℃时也显示出良好的可逆吸氢/放氢循环。催化和未催化的MgH₂的氢解吸动力学可以通过一个考虑表面条件的修正一级反应模型来理解。
We examined the catalytic effect of nanoparticle 3d-transition metals on hydrogen desorption (HD) properties of MgH2 prepared by mechanical ball milling method. All the MgH2 composites prepared by adding a small amount of nanoparticle Fe-nano, Co-nano, Ni-nano, and Cu-nano metals and by ball milling for 2 h showed much better HD properties than the pure ball-milled MgH2 itself. In particular, the 2 mol % Ni-nano-doped MgH2 composite prepared by soft milling for a short milling time of 15 min under a slow milling revolution speed of 200 rpm shows the most superior hydrogen storage properties: A large amount of hydrogen (similar to 6.5 wt %) is desorbed in the temperature range from 150 to 250 degrees C at a heating rate of 5 degrees C/min under He gas flow with no partial pressure of hydrogen. The EDX micrographs corresponding to Mg and Ni elemental profiles indicated that nanoparticle Ni metals as catalyst homogeneously dispersed on the surface of MgH2. In addition, it was confirmed that the product revealed good reversible hydriding/dehydri ding cycles even at 150 degrees C. The hydrogen desorption kinetics of catalyzed and noncatalyzed MgH2 could be understood by a modified first-order reaction model, in which the surface condition was taken into account.