Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China.
Soft Matter. 2017 May 31;13(21):3994-4000. doi: 10.1039/c7sm00607a.
Graphene is an ideal membrane for selective separation because of its unique properties and single-layer structure. Considerable efforts have been made to alter the permeability of graphene. In this study, we investigate the pathways for an oxygen atom to pass through graphene sheets. We also identify the effect of the ripple's curvature in graphene sheets on the energy barrier of permeation through density functional theory calculations. Results show that oxygen atoms can easily pass through the concave side of graphene ripples with a large curvature. The analysis of transition states reveals that the space where an oxygen atom passes through keeps an almost identical structure with similar bond lengths regardless of the curvature. We find that the Cu(111) substrate may draw out the C-C bond lengths of graphene at the Cu(111) surface because of the strong interaction between the graphene edge and copper atoms. Consequently, the energy barrier of the permeation of oxygen atoms through graphene is reduced. These results suggest that the rippling of graphene significantly affects its permeation.
石墨烯因其独特的性质和单层结构而成为理想的选择分离膜。人们已经做出了相当大的努力来改变石墨烯的渗透性。在这项研究中，我们研究了氧原子通过石墨烯片的途径。我们还通过密度泛函理论计算确定了石墨烯片波纹曲率对渗透能垒的影响。结果表明，氧原子可以很容易地通过具有大曲率的石墨烯波纹的凹侧通过。对过渡态的分析表明，无论曲率如何，氧原子通过的空间都保持着几乎相同的结构，具有相似的键长。我们发现，由于石墨烯边缘和铜原子之间的强烈相互作用，Cu(111) 衬底可能会拉出石墨烯在 Cu(111)表面的 C-C 键长。因此，氧原子通过石墨烯的渗透能垒降低。这些结果表明，石墨烯的波纹对其渗透有显著影响。
