Hydrogen-induced magnesium-zirconium interfacial coupling: enabling fast hydrogen sorption at lower temperatures
Hydrogen-induced magnesium-zirconium interfacial coupling: enabling fast hydrogen sorption at lower temperatures
复制标题
氢诱导镁-锆界面耦合：在较低温度下实现快速氢吸附
DOI：
10.1039/c7ta00460e
复制
发表时间：
2017-03-14
影响因子：
11.9
通讯作者：
Zhang, Qingan
中科院分区：
文献类型：
--
作者：
Ding, Xiaoli;Li, Yongtao;Zhang, Qingan
镁（Mg）作为储氢介质的应用长期以来受到限制，因为它在高温下吸氢相当缓慢。在这里，我们报告了一种利用氢诱导的 Mg-Zr 界面耦合来操纵氢原子迁移的方法，从而调节其在微米级富镁复合材料中的吸收和释放。通过在氢气氛下对 MgH2 和 Zr 粉末进行高压球磨和等温处理，在原位组装相关的 Mg-Zr-H 界面。 MgH2 解吸时界面逐渐分解，但吸收后又恢复其原始组成，而源自 Zr 氢化的 ZrH2 保持完全不变。与纯MgH2相比，Mg-Zr-H复合材料在较低温度下的吸氢速度显着加快，不仅在100℃下2小时内吸收接近饱和的氢气，而纯Mg根本不吸氢，而且在大约235℃时开始释放氢气，解吸活化能降低了大约40 kJ mol(-1)。这些显着的增强不能仅用 MgH2 晶粒尺寸的减小来解释，而很可能是由于 Mg-Zr-H 界面和大量缺陷的引入，这些缺陷为氢容易离解和迁移到 Mg/MgH2 基体中提供了通道。
The implementation of magnesium (Mg) as a hydrogen-storage medium has long been restricted because of its rather sluggish hydrogen sorption at high temperatures. Here, we report a method for using hydrogen-induced Mg-Zr interfacial coupling to manipulate the migration of hydrogen atoms and thus tune their uptake and release in a micrometer-sized Mg-rich composite. The associated Mg-Zr-H interfaces were assembled in situ by high-pressure ball milling and isothermal treatment of MgH2 and Zr powders under a hydrogen atmosphere. The interfaces gradually disintegrated upon MgH2 desorption but also recovered their original compositions upon absorption while the ZrH2 originating from Zr hydrogenation remained completely unchanged. Compared to pure MgH2, the hydrogen sorption of the Mg-Zr-H composite was thus shown to be dramatically faster at lower temperatures, whereby it not only absorbed hydrogen close to saturation at 100 degrees C within 2 h, while the pure Mg did not absorb hydrogen at all, but also started to release hydrogen at similar to 235 degrees C with a reduction in the activation energy of desorption by similar to 40 kJ mol(-1). These remarkable enhancements cannot be explained by the decrease in the size of the MgH2 grains alone but are most likely due to the introduction of Mg-Zr-H interfaces and large fractions of defects that provide channels for facile hydrogen dissociation and migration into the Mg/MgH2 matrix.