Charged fullerenes as high-capacity hydrogen storage media.
Charged fullerenes as high-capacity hydrogen storage media.
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DOI：
10.1021/nl070809a
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发表时间：
2007-08
期刊：
影响因子：
10.8
通讯作者：
M. Yoon;Shenyuan Yang;E. Wang;Zhenyu Zhang
中科院分区：
文献类型：
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作者：
M. Yoon;Shenyuan Yang;E. Wang;Zhenyu Zhang
利用密度泛函理论中的第一性原理计算方法，系统地研究了荷电碳富勒烯Cn（20 <or= n <or= 82）作为储氢介质的容量.我们发现，无论是带正电荷或带负电荷的富勒烯上的分子氢的结合强度可以显着提高到0.18-0.32 eV，潜在的室温，近环境应用的理想范围。增强的结合本质上是离域的，围绕着带电富勒烯的整个表面，并且归因于氢分子通过带电富勒烯表面附近产生的高电场的极化。在完全氢覆盖下，这些带电富勒烯可以获得高达约8.0重量%的存储容量。我们还发现，与直觉预期相反，含有封装的金属原子的富勒烯仅表现出可忽略不计的氢键强度增强，因为由金属原子捐赠的电荷主要被限制在富勒烯笼内。这些预测可能有助于寻找一类新的高容量储氢介质。
Using first-principles calculations within density functional theory, we explore systematically the capacity of charged carbon fullerenes Cn (20 <or= n <or= 82) as hydrogen storage media. We find that the binding strength of molecular hydrogen on either positively or negatively charged fullerenes can be dramatically enhanced to 0.18-0.32 eV, a desirable range for potential room-temperature, near ambient applications. The enhanced binding is delocalized in nature, surrounding the whole surface of a charged fullerene, and is attributed to the polarization of the hydrogen molecules by the high electric field generated near the surface of the charged fullerene. At full hydrogen coverage, these charged fullerenes can gain storage capacities of up to approximately 8.0 wt %. We also find that, contrary to intuitive expectation, fullerenes containing encapsulated metal atoms only exhibit negligible enhancement in the hydrogen binding strength, because the charge donated by the metal atoms is primarily confined inside the fullerene cages. These predictions may prove to be instrumental in searching for a new class of high-capacity hydrogen storage media.