The Thinnest Molecular Separation Sheet by Graphene Gates of Single-Walled Carbon Nanohorns
The Thinnest Molecular Separation Sheet by Graphene Gates of Single-Walled Carbon Nanohorns
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DOI：
10.1021/nn504162s
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发表时间：
2014-11-01
期刊：
影响因子：
17.1
通讯作者：
Ohba, Tomonori
中科院分区：
文献类型：
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作者：
Ohba, Tomonori
石墨烯可能是可用作分子分离门的最薄的膜。包括吸收、低温蒸馏、吸附和膜分离在内的几种技术已被用于构建分离系统。使用石墨烯作为膜的分子分离已经被研究，因为通过化学气相沉积可以大面积合成石墨烯。控制栅极尺寸对于在石墨烯膜中实现高分离性能是必要的。石墨烯和氧化石墨烯层的分子和离子分离可以通过石墨烯的本征缺陷和缺陷捐赠来实现。然而，石墨烯栅极的可控性仍存在争议，因为对于最薄的石墨烯膜的制造来说，皮米级别的栅极尺寸控制是不可避免的。在本文中，在单壁碳纳米角（NHs）的石墨烯片中的控制栅极尺寸进行了研究，并通过分子探针与CO2，O2-，N2-，CH 4，SF6的石墨烯片的分子分离能力进行了评估。制备具有310 μ π ι、370 μ π ι和>500 μ π ι的不同尺寸栅极的NH中的石墨烯片，并通过分子探测进行评估。石墨烯片中的310 μ m栅极可以分离所测试的分子，而对于370 μ m栅极观察到弱分离特性。穿透310 μ m栅的CO2的量比CH 4的量大35倍以上。这些结果得到了分子通过石墨烯片中的300、400和700 μ m门的渗透的分子动力学模拟的支持。因此，使用340 μ m厚的石墨烯片的气体分离膜具有高潜力。这些发现提供了毫不含糊的证据，证明了石墨烯栅极在皮米级的重要性。控制栅极是由石墨烯制成的高性能分离膜的主要挑战。
Graphene is possibly the thinnest membrane that could be used as a molecular separation gate. Several techniques including absorption, cryogenic distillation, adsorption, and membrane separation have been adopted for constructing separation systems. Molecular separation using graphene as the membrane has been studied because large area synthesis of graphene is possible by chemical vapor deposition. Control of the gate sizes is necessary to achieve high separation performances in graphene membranes. The separation of molecules and ions using graphene and graphene oxide layers could be achieved by the intrinsic defects and defect donation of graphene. However, the controllability of the graphene gates is still under debate because gate size control at the picometer level is inevitable for the fabrication of the thinnest graphene membranes. In this paper, the controlled gate size in the graphene sheets in single-walled carbon nanohorns (NHs) is studied and the molecular separation ability of the graphene sheets is assessed by molecular probing with CO2, O-2, N-2, CH4, and SF6. Graphene sheets in NHs with different sized gates of 310, 370, and >500 pm were prepared and assessed by molecular probing. The 310 pm-gates in the graphene sheets could separate the molecules tested, whereas weak separation properties were observed for 370 pm-gates. The amount of CO2 that penetrated the 310 pm-gates was more than 35 times larger than that of CH4. These results were supported by molecular dynamics simulations of the penetration of molecules through 300, 400, and 700 pm-gates in graphene sheets. Therefore, a gas separation membrane using a 340-pm-thick graphene sheet has high potential. These findings provide unambiguous evidence of the importance of graphene gates on the picometer level. Control of the gates is the primary challenge for high-performance separation membranes made of graphene.