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Title: Ion-Gated Gas Separation through Porous Graphene

Abstract

Porous graphene holds great promise as an atom-thin, high-permeance membrane for gas separation, but to precisely control the pore size at three to five angstroms proves challenging. Here we propose an ion-gated graphene membrane comprising a monolayer of ionic liquid coated porous graphene to dynamically modulate the pore size to achieve selective gas separation. This approach enables the otherwise non-selective large pores on the order of 1 nm in size to be selective for gases whose diameters range from three to four angstroms. We show from molecular dynamics simulations that CO 2, N 2 and CH 4 all can permeate through a 1-nm pore in graphene without any selectivity. But when a monolayer of [emim][BF 4] is deposited on the porous graphene, CO 2 has much higher permeance than the other two gases. We find that the anion dynamically modulates the pore size by hovering above the pore and provides affinity for CO 2 while the larger cation (which cannot go through the pore) holds the anion in place via electrostatic attraction. This composite membrane is especially promising for CO 2/CH 4 separation, with a CO 2/CH 4 selectivity of about 42 and CO 2 permeance ~105 GPU (gas permeationmore » unit). We further demonstrate that selectivity and permeance can be tuned by the anion size. The present work points toward a promising direction of using the atom-thin ionic-liquid/porous-graphene hybrid membrane for high-permeance, selective gas separation that allows a greater flexibility in substrate pore size control.« less

Authors:
 [1];  [2]; ORCiD logo [3]; ORCiD logo [1]
  1. Univ. of California, Riverside, CA (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1348344
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 17; Journal Issue: 3; Journal ID: ISSN 1530-6984
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Tian, Ziqi, Mahurin, Shannon M., Dai, Sheng, and Jiang, De-en. Ion-Gated Gas Separation through Porous Graphene. United States: N. p., 2017. Web. doi:10.1021/acs.nanolett.6b05121.
Tian, Ziqi, Mahurin, Shannon M., Dai, Sheng, & Jiang, De-en. Ion-Gated Gas Separation through Porous Graphene. United States. doi:10.1021/acs.nanolett.6b05121.
Tian, Ziqi, Mahurin, Shannon M., Dai, Sheng, and Jiang, De-en. Fri . "Ion-Gated Gas Separation through Porous Graphene". United States. doi:10.1021/acs.nanolett.6b05121. https://www.osti.gov/servlets/purl/1348344.
@article{osti_1348344,
title = {Ion-Gated Gas Separation through Porous Graphene},
author = {Tian, Ziqi and Mahurin, Shannon M. and Dai, Sheng and Jiang, De-en},
abstractNote = {Porous graphene holds great promise as an atom-thin, high-permeance membrane for gas separation, but to precisely control the pore size at three to five angstroms proves challenging. Here we propose an ion-gated graphene membrane comprising a monolayer of ionic liquid coated porous graphene to dynamically modulate the pore size to achieve selective gas separation. This approach enables the otherwise non-selective large pores on the order of 1 nm in size to be selective for gases whose diameters range from three to four angstroms. We show from molecular dynamics simulations that CO2, N2 and CH4 all can permeate through a 1-nm pore in graphene without any selectivity. But when a monolayer of [emim][BF4] is deposited on the porous graphene, CO2 has much higher permeance than the other two gases. We find that the anion dynamically modulates the pore size by hovering above the pore and provides affinity for CO2 while the larger cation (which cannot go through the pore) holds the anion in place via electrostatic attraction. This composite membrane is especially promising for CO2/CH4 separation, with a CO2/CH4 selectivity of about 42 and CO2 permeance ~105 GPU (gas permeation unit). We further demonstrate that selectivity and permeance can be tuned by the anion size. The present work points toward a promising direction of using the atom-thin ionic-liquid/porous-graphene hybrid membrane for high-permeance, selective gas separation that allows a greater flexibility in substrate pore size control.},
doi = {10.1021/acs.nanolett.6b05121},
journal = {Nano Letters},
number = 3,
volume = 17,
place = {United States},
year = {Fri Feb 10 00:00:00 EST 2017},
month = {Fri Feb 10 00:00:00 EST 2017}
}

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