Abstract
Precise functionalization of electrodes with size-selected ionic liquid (IL) clusters may improve the application of ILs in electrochemical separations. Herein we report our combined experimental and theoretical investigation of the IL clusters 1-ethyl-3-methylimidazolium tetrafluoroborate [EMIM]n[BF4]n+1- (n = 1-9) and demonstrate their selectivity and efficiency toward targeted adsorption of ions from solution. The structures and energies of the IL clusters, predicted with global optimization, agree with and help interpret the ion abundances and stabilities measured by high-mass-resolution electrospray ionization mass spectrometry and collision-induced dissociation experiments. The [EMIM][BF4]2- cluster, which was identified as the most stable IL cluster, was selectively soft-landed onto a working electrode. Electrochemical impedance spectroscopy revealed a lower charge transfer resistance on the soft-landed electrode containing [EMIM][BF4]2- compared with an electrode prepared by drop-casting of an IL solution containing the full range of IL clusters. Our findings indicate that specific IL clusters may be used to increase the efficiency of electrochemical separations by lowering the overpotentials involved.
Original language | English |
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Pages (from-to) | 6844-6851 |
Number of pages | 8 |
Journal | Journal of Physical Chemistry Letters |
Volume | 11 |
Issue number | 16 |
DOIs | |
State | Published - Aug 20 2020 |
Externally published | Yes |
Funding
This work was supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. Part of this work was performed using EMSL, a National Scientific User Facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is a multiprogram national laboratory operated for DOE by Battelle for the U.S. Department of Energy under Contract DE-AC05-76RL01830. Computer resources were provided by Research Computing at PNNL and the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility operated under Contract DE-AC02-05CH11231.
Funders | Funder number |
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U.S. Department of Energy | |
Office of Science | DE-AC02-05CH11231 |
Basic Energy Sciences | |
Biological and Environmental Research | |
Pacific Northwest National Laboratory | DE-AC05-76RL01830 |
Chemical Sciences, Geosciences, and Biosciences Division |