Thermodynamics and kinetics of gas storage in porous liquids

Journal Article · Tue Jul 05 00:00:00 EDT 2016 · Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry

DOI:https://doi.org/10.1021/acs.jpcb.6b04784· OSTI ID:1287030

Zhang, Fei ^[1]; Yang, Fengchang ^[1]; Huang, Jingsong ^[2]; Sumpter, Bobby G. ^[2]; Qiao, Rui ^[1]

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1. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

The recent synthesis of organic molecular liquids with permanent porosity (Giri et al., Nature, 2015, 527, 216) opens up exciting new avenues for gas capture, storage, and separation. Using molecular dynamics simulations, we study the thermodynamics and kinetics for the storage of CH₄, CO₂, and N₂ molecules in porous liquids consisting of crown-ether substituted cage molecules in a 15-crown-5 solvent. It is found that the gas storage capacity per cage molecule follows the order of CH₄ > CO₂ > N₂, which does not correlate simply with the size of gas molecules. Different gas molecules are stored inside the cage differently, e.g., CO₂ molecules prefer the cage s core while CH₄ molecules favor both the core and the branch regions. All gas molecules considered can enter the cage essentially without energy barriers, and their dynamics inside the cage are only slightly hindered by the nanoscale confinement. In addition, all gas molecules can leave the cage on nanosecond time scale by overcoming a modest energy penalty. The molecular mechanisms of these observations are clarified.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS); Energy Frontier Research Centers (EFRC) (United States). Center for Understanding and Control of Acid Gas-induced Evolution of Materials for Energy (UNCAGE-ME)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC05-00OR22725; SC0012577
• OSTI ID: 1287030
• Journal Information: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry, Vol. 120, Issue 29; ISSN 1520-6106
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

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