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

Abstract

a b s t r a c tTwo-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 conduct a transient non-equilibrium molecular dynamics simulation on its molecular sieving effects. The distinct time-varying molecular crossing numbers show that this special nanopore can efficiently sieve CO 2 and H 2 S molecules from CH 4 molecules with high selectivity. By analyzing the molecular structure and pore functionalization-related molecular orientation and permeable zone in the nanopore, density distribution 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 functionalization, as gas separation membranes are summarized based on the identified phenomena and mechanisms.

Quasi-Unidirectional Transport Bilayer Two-Dimensional Nanopores for Highly-Efficient Molecular Sieving

“…The bond and angle potentials in the gas molecules (CO 2 ) and the functionalized groups are all modeled by harmonic potential. The parameters in these potential models can refer to our previous work (Sun and Bai, 2017). The charges on the atoms near the pore are obtained through a density functional theory calculation using the DMol 3 module in Material Studio software.…”

“…The graphene-hBN bilayer nanopore is constructed by stacking the graphene and hBN layers together and generating a nanopore with the same size (Figure 1A). To realize a selectivity of the separation of CO 2 /CH 4 mixtures, the pores are functionalized by the N and H atoms (Figure 1B), as done in our early work (Sun and Bai, 2017). The N functionalization not only enlarges the size of the pore to achieve a high permeance of CO 2 molecules, but also enhances the adsorption intensities of CO 2 molecules on the surface which further improves the permeability and selectivity.…”

Interfacial Bonding Energy on the Interface between ZChSnSb/Sn Alloy Layer and Steel Body at Microscale

“…In order to achieve surface energy optimization, only the atoms on the surface layers were optimized. The minimizer system structure is improved so as to achieve the most stable configuration [ 16 ]. The wave energy in the subsequent dynamics simulation became smaller, and the convergence time became shorter.…”

Sandwich layered double hydroxides with graphene oxide for enhanced water desalination

“…2D-material-based membranes receive widespread attention for their facile fabrication [1], efficient chemical modification [2], and tunable channel size [3], which boost various applications in areas such as precise ionic sieving [4][5][6], energy conversion and storage [7], and other biomimetic nanofluidic devices [8][9][10]. To date, a variety of 2D nano-building-blocks are used for constructing layered membranes [11], for example, graphene oxide (GO) [12][13][14], transition metal dichalcogenides (TMDs) [15][16][17], and metal-organic frameworks (MOFs) [18,19].…”