Abstract
Porous liquids are a promising new class of materials featuring nanoscale cavity units dispersed in liquids that are suitable for applications such as gas storage and separation. In this work, we use molecular dynamics simulations to examine the multicomponent gas storage in a porous liquid consisting of crown-ether-substituted cage molecules dissolved in a 15-crown-5 solvent. We compute the storage of three prototypical small molecules including CO2, CH4, and N2 and their binary mixtures in individual cage molecules. For porous liquids in equilibrium with a binary 1:1 gas mixture bath with partial gas pressure of 27.5 bar, a cage molecule shows a selectivity of 4.3 and 13.1 for the CO2/CH4 and CO2/N2 pairs, respectively. We provide a molecular perspective of how gas molecules are stored in the cage molecule and how the storage of one type of gas molecule is affected by other types of gas molecules. Our results clarify the molecular mechanisms behind the selectivity of such cage molecules toward different gases. (Figure Presented).
Original language | English |
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Pages (from-to) | 12426-12433 |
Number of pages | 8 |
Journal | Journal of Physical Chemistry C |
Volume | 121 |
Issue number | 22 |
DOIs | |
State | Published - Jun 8 2017 |
Funding
We thank the ARC at Virginia Tech for generous allocations of computer time. We also thank the anonymous referees for helpful suggestions. R.Q. was partially supported by an appointment to the HERE program for faculty at the Oak Ridge National Laboratory (ORNL) administered by ORISE. B.G.S. and J.H. acknowledge work done at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. B.G.S. acknowledges support from the Center for Understanding and Control of Acid Gas-Induced Evolution of Materials for Energy (UNCAGE-ME), an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences.