Harvesting Energy from Water Flow over Graphene?
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- 作者：Jun Yin ; Zhuhua Zhang ; Xuemei Li ; Jianxin Zhou ; Wanlin Guo
- 刊名：Nano Letters
- 出版年：2012
- 出版时间：March 14, 2012
- 年：2012
- 卷：12
- 期：3
- 页码：1736-1741
- 全文大小：313K
- 年卷期：v.12,no.3(March 14, 2012)
- ISSN：1530-6992
文摘
It is reported excitingly in a previous letter (Nano Lett.2011, 11, 3123) that a small piece of graphene sheet about 30 脳 16 渭m2 immersed in flowing water with 0.6 M hydrochloric acid can produce voltage 20 mV. Here we find that no measurable voltage can be induced by the flow over mono-, bi- and trilayered graphene samples of 1 脳 1.5 cm2 in size in the same solution once the electrodes on graphene are isolated from interacting with the solution, mainly because the H3O+ cations in the water adsorb onto graphene by strong covalent bonds as revealed by our first-principles calculations. When both the graphene and its metal electrodes are exposed to the solution as in the previous work, water flow over the graphene-electrode system can induce voltages from a few to over a hundred millivolts. In this situation, the graphene mainly behaves as a load connecting between the electrodes. Therefore, the harvested energy is not from the immersed carbon nanomaterials themselves in ionic water flow but dominated by the exposed electrodes.