Enhanced Hydrogen Storage Properties of Mg鈥揟i鈥揤 Nanocomposite at Moderate Temperatures
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- 作者：Tong Liu ; Chunguang Chen ; Hui Wang ; Ying Wu
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：October 2, 2014
- 年：2014
- 卷：118
- 期：39
- 页码：22419-22425
- 全文大小：424K
- ISSN：1932-7455
文摘
With the purpose of improving the hydrogen sorption kinetics of Mg at moderate temperatures, the Mg鈥揟iH1.971鈥揤H2 nanocomposite is synthesized by means of the hydrogen plasma鈥搈etal reaction (HPMR) approach. The nanocomposite is consequently hydrogenated and dehydrogenated at 673 K to synthesize Mg鈥?.6 wt % Ti鈥?.9 wt % V nanocomposite. The Mg Nanoparticles (NPs) in hexagonal shape range from 30 to 300 nm. The spherical Ti and V NPs of about 23 nm are uniformly distributed on the surfaces of the Mg NPs. The Mg鈥揟i鈥揤 nanocomposite quickly absorbs 4.7 wt % H2 within 5 min at 473 K and 2.5 wt % H2 within 10 min at 373 K. The apparent activation energies for hydrogenation and dehydrogenation are 29.2 and 73.8 kJ mol鈥?, respectively. During the hydrogenation/dehydrogenation cycle, the Ti and V NPs restrain the growth of Mg NPs. The dehydrogenation of TiH1.971 to Ti is interpreted as the catalytic impact of V NPs. The improved sorption kinetics at moderate temperatures and the reduced activation energy derive from the nanostructure of Mg and the synergic catalytic impact of Ti and V NPs.