He Yuping, Zhao Yiping
Department of Physics and Astronomy, and Nanoscale Science and Engineering Center, University of Georgia, Athens, GA 30602, USA.
Nanotechnology. 2009 May 20;20(20):204008. doi: 10.1088/0957-4484/20/20/204008. Epub 2009 Apr 23.
A 2.25 at.% V decorated Mg nanoblade array has been fabricated by a dynamic shadowing growth technique. It can absorb and desorb hydrogen rapidly at temperatures T>500 K after activation by one hydrogenation cycling, with low hydrogen absorption activation energy of 35.0 +/- 1.2 kJ/mol H2 and desorption activation energy of 65.0 +/- 0.3 kJ/mol H2. The saturated hydrogen content in Mg nanoblades decreases gradually with the number of cyclings, which is mainly caused by the formation and growth of Mg2Si hillock defects at the nanoblade/substrate interface even though a diffusion barrier layer consisting of a 500 nm Ti nanorod array and 500 nm Ti film was deposited between the Mg nanoblades and the Si substrate. The improved hydrogen sorption kinetics is attributed to both the catalytic effect of the V coating and the unique nanoblade morphology with large surface area and small hydrogen diffusion length.
通过动态阴影生长技术制备了一种含2.25原子百分比钒的修饰镁纳米刀片阵列。在经过一次氢化循环活化后，它在温度T>500 K时能够快速吸氢和解吸氢，吸氢活化能低至35.0±1.2 kJ/mol H₂，解吸活化能为65.0±0.3 kJ/mol H₂。镁纳米刀片中的饱和氢含量随着循环次数逐渐降低，这主要是由于在纳米刀片/衬底界面处形成并生长了Mg₂Si小丘缺陷，尽管在镁纳米刀片和硅衬底之间沉积了由500 nm钛纳米棒阵列和500 nm钛膜组成的扩散阻挡层。氢吸附动力学的改善归因于钒涂层的催化作用以及具有大表面积和小氢扩散长度的独特纳米刀片形态。
