Molecular sieving through a graphene nanopore： non-equilibrium molecular dynamics simulation

• Published in: Science bulletin (Beijing) 2017-04, Vol.62 (8), p.554-562
• Main Authors: Sun, Chengzhen, Bai, Bofeng
• Format: Article
• Language: English
• Subjects: Gas separation membrane; Graphene nanopore; Molecular dynamics; Molecular sieve; 分子动力学模拟; 分子杂交; 分子筛; 改性石墨; 气体分离膜; 筛分效果; 纳米孔; 非平衡
• ISSN: 2095-9273
• DOI: 10.1016/j.scib.2017.03.004

Two-dimensional graphene nanopores have shown great promise as ultra-permeable molecular sieves based on their size-sieving effects. We design a nitrogen/hydrogen modified graphene nanopore and con- duct a transient non-equilibrium molecular dynamics simulation on its molecular sieving effects. The dis- tinct time-varying molecular crossing numbers show that this special nanopore can efficiently sieve CO2 and H2S molecules from CH4 molecules with high selectivity. By analyzing the molecular structure and pore functionalization-related molecular orientation and permeable zone in the nanopore, density distri- bution in the molecular adsorption layer on the graphene surface, as well as other features, the molecular sieving mechanisms of graphene nanopores are revealed. Finally, several implications on the design of highly-efficient graphene nanopores, especially for determining the porosity and chemical functionaliza tion, as gas separation membranes are summarized based on the identified phenomena and mechanisms.