Harvesting energy from water flow over graphene?
Harvesting energy from water flow over graphene?
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DOI：
10.1021/nl300636g
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发表时间：
2012
期刊：
影响因子：
10.8
通讯作者：
Jun Yin;Zhuhua Zhang;Xuemei Li;Jianxin Zhou;Wanlin Guo
中科院分区：
文献类型：
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作者：
Jun Yin;Zhuhua Zhang;Xuemei Li;Jianxin Zhou;Wanlin Guo
在之前的一篇文章（Nano Lett. 2011, 11,3123）中，令人兴奋的报道了一小块约30 × 16 μm(2)的石墨烯片浸入含有0.6 M盐酸的流动水中可以产生~20 mV的电压。在这里，我们发现，一旦石墨烯上的电极与溶液相互作用分离，在相同的溶液中，单层、双层和三层石墨烯样品（~1 × 1.5 cm(2)）的流动不会产生可测量的电压，这主要是因为水中的H(3)O（+）阳离子通过强共价键吸附在石墨烯上，正如我们的第一原理计算所揭示的那样。在之前的研究中，当石墨烯和它的金属电极都暴露在溶液中时，流过石墨烯电极系统的水流会产生从几毫伏到一百毫伏以上的电压。在这种情况下，石墨烯主要充当连接电极之间的负载。因此，所收集的能量不是来自离子水流中浸入的碳纳米材料本身，而是由暴露的电极主导。
It is reported excitingly in a previous letter (Nano Lett. 2011, 11, 3123) that a small piece of graphene sheet about 30 × 16 μm(2) 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 × 1.5 cm(2) in size in the same solution once the electrodes on graphene are isolated from interacting with the solution, mainly because the H(3)O(+) 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.