Hydrogen storage properties of nano-structured 0.65MgH2/0.35ScH2
Hydrogen storage properties of nano-structured 0.65MgH2/0.35ScH2
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DOI：
10.1016/j.ijhydene.2012.10.025
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发表时间：
2013-01
影响因子：
7.2
通讯作者：
Xuanli Luo;D. Grant;G. Walker
中科院分区：
文献类型：
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作者：
Xuanli Luo;D. Grant;G. Walker
发现金属间化合物Mg0.65Sc0.35在高达350 °C的温度下经过氢化（脱）循环后形成纳米结构的金属氢化物复合体系。在脱氢时发生相分离，形成富Mg和富Sc的氢化物相，通过SEM和TEM清楚地观察到富Sc的氢化物相作为尺寸在40至100 nm范围内的纳米团簇分布在富Mg/MgH 2相中。金属间化合物Mg0.65Sc0.35表现出良好的吸氢性能，约为0.01%。6.4重量百分比，在150 °C下的第一次充氢循环和随后的氢化（脱）循环中，可逆氢容量（高达4.3重量%）实现了。与原始MgH 2相比，复合材料具有更快的循环动力学，活化能Ea从159 ± 1 kJ mol− 1显著降低至82 ± 1 kJ mol−1（由Kissinger图确定）。通过DSC和压力-组成-等温线（PCI）测量观察到两个脱氢事件，其中主要脱氢事件归因于富镁氢化物相。此外，在最初的两个循环之后，储氢容量在接下来的55个（脱）氢化循环中保持不变。
The intermetallic compound Mg0.65Sc0.35was found to form a nano-structured metal hydride composite system after a (de)hydrogenation cycle at temperatures up to 350 °C. Upon dehydrogenation phase separation occurred forming Mg-rich and Sc-rich hydride phases that were clearly observed by SEM and TEM with the Sc-rich hydride phase distributed within Mg/MgH2-rich phase as nano-clusters ranging in size from 40 to 100 nm. The intermetallic compound Mg0.65Sc0.35showed good hydrogen uptake, ca. 6.4 wt.%, in the first charging cycle at 150 °C and in the following (de)hydrogenation cycles, a reversible hydrogen capacity (up to 4.3 wt.%) was achieved. Compared to the as-received MgH2, the composite had faster cycling kinetics with a significant reduction in activation energy Eafrom 159 ± 1 kJ mol−1to 82 ± 1 kJ mol−1(as determined from a Kissinger plot). Two-dehydrogenation events were observed by DSC and pressure–composition-isotherm (PCI) measurements, with the main dehydrogenation event being attributed to the Mg-rich hydride phase. Furthermore, after the initial two cycles the hydrogen storage capacity remained unchanged over the next 55 (de)hydrogenation cycles.