Nanosize-Controlled Reversibility for a Destabilizing Reaction in the LiBH4鈥揘dH2+x System
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- 作者：Weitong Cai ; Hui Wang ; Dalin Sun ; Min Zhu
- 刊名：The Journal of Physical Chemistry C
- 出版年：2013
- 出版时间：May 16, 2013
- 年：2013
- 卷：117
- 期：19
- 页码：9566-9572
- 全文大小：410K
- 年卷期：v.117,no.19(May 16, 2013)
- ISSN：1932-7455
文摘
A reversible reaction, 4LiBH4 + NdH2聽鈫?NdB4 + 4LiH + 7H2, which destabilizes the dehydrogenation thermodynamics of LiBH4, has been found in the present work. Significantly, we prove that the reversibility only exists when NdH2+x is in size of less than about 10 nm. With this reaction, the estimated dehydrogenation enthalpy change is reduced from 74 kJ mol鈥? H2 for pristine LiBH4 to 64 kJ mol鈥? H2; the theoretical hydrogen capacity is 6.0 wt %, and there is no emission of deleterious BH3 and B2H6. Moreover, the dehydrogenation kinetics of this reaction are fast鈥?.0 wt % hydrogen was released within 1.5 h at 370 掳C. When the NdH2+x becomes stable owing to its significant growth, the thermodynamic destabilization effect does not occur after several hydrogenation/dehydrogenation cycles. However, the presence of NdH2+x also has a positive effect upon the dehydrogenation kinetics of LiBH4. This novel finding is beneficial for modifying the reversibility of the reactive hydride composite systems through nanosize controlling.