Hanada Nobuko, Ichikawa Takayuki, Fujii Hironobu
Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan.
J Phys Chem B. 2005 Apr 21;109(15):7188-94. doi: 10.1021/jp044576c.
We examined the catalytic effect of nanoparticle 3d-transition metals on hydrogen desorption (HD) properties of MgH(2) prepared by mechanical ball milling method. All the MgH(2) 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 MgH(2) itself. In particular, the 2 mol % Ni(nano)-doped MgH(2) 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 ( approximately 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 MgH(2). In addition, it was confirmed that the product revealed good reversible hydriding/dehydriding cycles even at 150 degrees C. The hydrogen desorption kinetics of catalyzed and noncatalyzed MgH(2) could be understood by a modified first-order reaction model, in which the surface condition was taken into account.
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，其HD性能均比纯球磨MgH₂本身好得多。特别是，在200 rpm的慢磨转速下软磨15分钟的短磨时间制备的2 mol％Ni（纳米）掺杂的MgH₂复合材料表现出最优异的储氢性能：在He气流且无氢分压的情况下，以5℃/min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％）。对应于Mg和Ni元素分布的EDX显微照片表明，纳米颗粒Ni金属作为催化剂均匀地分散在MgH₂表面。此外，已证实该产物即使在150℃下也显示出良好的可逆氢化/脱氢循环。催化和未催化的MgH₂的氢解吸动力学可以通过考虑表面条件的修正一级反应模型来理解。
