Abstract：
As a material with high specific surface area and excellent chemical stability, graphene exhibited remarkable adsorption and separation performance as well as a wide range of potential applications. The graphene layer played a significant role in influencing gas transmission. In this study, we employed molecular dynamics simulation to investigate the diffusion characteristics and local structures of a mixed system consisting of CH4 , CO2 , SO2 and H2 O. Additionally, we further examined the transformation of the behavior of these mixtures within graphene layers. The order of diffusion coefficients of the four molecules without graphene was H2 O>SO2 >CO2 ≫CH4 . However, in the double-layer graphene, the order changed to CH4 >CO2 ≫H2 O>SO2 . Higher temperatures and lower pressures were found to facilitate gas diffusion. Temperature and pressure had great effects on the local structures of CH4 , CO2 and SO2 , while their impact on H2 O was limited due to the extensive network of hydrogen bonds formed by H2 O molecules. The statistical results of average coordination number revealed that CH4 tended to aggregate with itself, whereas CO2 and SO2 exhibited a tendency to aggregate with H2 O. The graphene structure enhanced the separation and transportation of CH4 from mixed systems.
摘要：
作为一种具有高比表面积和优异的化学稳定性的材料，石墨烯具有显著的吸附和分离性能以及广泛的潜在应用。石墨烯层在影响气体传输方面发挥了重要作用。在这项研究中,我们采用分子动力学模拟来研究由CH4组成的混合系统的扩散特性和局部结构，CO2,SO2和H2O.此外，我们进一步检查了这些混合物在石墨烯层内的行为的转变。没有石墨烯的四个分子的扩散系数的顺序为H2O>SO2>CO2>CH4。然而,在双层石墨烯中，顺序改为CH4>CO2>H2O>SO2。发现较高的温度和较低的压力有利于气体扩散。温度和压力对CH4的局部结构有很大的影响,CO2和SO2,由于H2O分子形成的氢键网络广泛，它们对H2O的影响有限。平均协调数的统计结果表明，CH4倾向于自身聚集，而CO2和SO2表现出与H2O聚集的趋势。石墨烯结构增强了CH4从混合体系中的分离和运输。
