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Title: Selectivity trend of gas separation through nanoporous graphene

By means of molecular dynamics (MD) simulations, we demonstrate that porous graphene can efficiently separate gases according to their molecular sizes. The flux sequence from the classical MD simulation is H{sub 2}>CO{sub 2}≫N{sub 2}>Ar>CH{sub 4}, which generally follows the trend in the kinetic diameters. This trend is also confirmed from the fluxes based on the computed free energy barriers for gas permeation using the umbrella sampling method and kinetic theory of gases. Both brute-force MD simulations and free-energy calcualtions lead to the flux trend consistent with experiments. Case studies of two compositions of CO{sub 2}/N{sub 2} mixtures further demonstrate the separation capability of nanoporous graphene. - Graphical abstract: Classical molecular dynamics simulations show the flux trend of H{sub 2}>CO{sub 2}≫N{sub 2}>Ar>CH{sub 4} for their permeation through a porous graphene, in excellent agreement with a recent experiment. - Highlights: • Classical MD simulations show the flux trend of H{sub 2}>CO{sub 2}≫N{sub 2}>Ar>CH{sub 4} for their permeation through a porous graphene. • Free energy calculations yield permeation barriers for those gases. • Selectivities for several gas pairs are estimated from the free-energy barriers and the kinetic theory of gases. • The selectivity trend is in excellent agreement with a recent experiment.
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [1]
  1. Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)
  2. Department of Chemistry, Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22475550
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 224; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ARGON; CARBON DIOXIDE; COMPUTERIZED SIMULATION; FREE ENERGY; GASES; GRAPHENE; HYDROGEN; MEMBRANES; METHANE; MIXTURES; MOLECULAR DYNAMICS METHOD; POROUS MATERIALS; REDUCTION; SAMPLING