Fluorine-Modified Porous Graphene as Membrane for CO2/N2 Separation: Molecular Dynamic and First-Principles Simulations

详细信息    查看全文

• 作者：Tiantian Wu ; Qingzhong Xue ; Cuicui Ling ; Meixia Shan ; Zilong Liu ; Yehan Tao ; Xiaofang Li
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：April 10, 2014
• 年：2014
• 卷：118
• 期：14
• 页码：7369-7376
• 全文大小：490K
• 年卷期：v.118,no.14(April 10, 2014)
• ISSN：1932-7455

文摘

It is demonstrated that the fluorine-modified porous graphene membrane has excellent selectivity for CO₂/N₂ separation by using molecular dynamic (MD) simulations. We also investigated in detail the mechanism of the fluorine-modified porous graphene membrane for CO₂/N₂ separation by using first-principles simulations. We find that the diffusion barriers for CO₂ and N₂ to pass through the pore-22 (with 22 carbon atoms drilled out) graphene membrane are relatively small, which indicates that the pore-22 has a low selectivity for CO₂/N₂ separation. After fluorine modification, the diffusion barrier for CO₂ to pass through decreases to 0.029 eV, while the diffusion barrier for N₂ greatly increases to 0.116 eV. Therefore, N₂ gets more difficult, while CO₂ gets easier to penetrate through the fluorine-modified pore-22. The fluorine-modified pore-22 porous graphene shows a great enhancement of selectivity for CO₂/N₂ separation, which is consistent with the MD results. Our studies show that first-principles simulations can be well used to understand the MD results and propose an economical and efficient means of separating CO₂ from N₂, which may be useful for designing new concept membranes for gas separation, like CO/N₂ and SO₂/N₂ separations.