Study of the imidazolium-based ionic liquid – Ag electrified interface on the CO2 electroreduction by sum frequency spectroscopy

Garcia Rey, Natalia

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https://hdl.handle.net/2142/96953 Copy

Description

Title

Study of the imidazolium-based ionic liquid – Ag electrified interface on the CO2 electroreduction by sum frequency spectroscopy

Author(s)

Garcia Rey, Natalia

Contributor(s)

Dlott, Dana

Issue Date

2017-06-21

Keyword(s)

Spectroscopy as an analytical tool

Abstract

Imidazolium based ionic liquids (ILs) have been used as a promising system to improve the CO$_{2}$ electroreduction at lower overpotential than other organic or aqueous electrolytes$^{1}$. Although the detailed mechanism of the CO$_{2}$ electroreduction on Ag has not been elucidated yet, we have developed a methodology to study the electrified interface during the CO$_{2}$ electroreduction using sum frequency generation (SFG) spectroscopy in combination with cyclic voltammetry$^{2}$. In this work, we tuned the composition of imidazolium-based ILs by exchanging the anion or the functional groups of the imidazolium. We use the nonresonant SFG (NR-SFG) to study the IL-Ag interface and resonant SFG (RES-SFG) to identify the CO adsorbed on the electrode and monitor the Stark shift as a function of cell potential. In previous studies on CO$_{2}$ electroreduction in the IL: 1-ethyl-3-methylimidazolium tetrafluorborate (EMIM-BF$_{4}$) on Ag, we showed three events occurred at the same potential (-1.33 V vs. Ag/AgCl): the current associated with CO$_{2}$ electroreduction increased, the Stark shift of the adsorbed atop CO doubled in magnitude and the EMIM-BF$_{4}$ underwent a structural transition$^{3}$. In addition, we also observed how the structural transition of the EMIM-BF$_{4}$ electrolyte shift to lower potentials when the IL is mixed with water. It is known that water enhances the CO$_{2}$ electroreduction producing more CO$^{4}$. Moreover, the CO is adsorbed in multi-bonded and in atop sites when more water is present in the electrolyte. _x000d_ _x000d_ $^{1}$Lau, G. P. S.; Schreier, M.; Vasilyev, D.; Scopelliti, R.; Grätzel, M.; Dyson, P. J., New Insights into the Role of Imidazolium-Based Promoters for the Electroreduction of CO$_{2}$ on a Silver Electrode. J. Am. Chem. Soc. 2016, 138, 7820-7823._x000d_ $^{2}$Garc'{i}a Rey, N.; Dlott, D. D., Studies of Electrochemical Interfaces by Broadband Sum Frequency Generation. J. Electroanal. Chem. 2016. DOI:10.1016/j.jelechem.2016.12.023._x000d_ $^{3}$Garc'{i}a Rey, N.; Dlott, D. D., Structural Transition in an Ionic Liquid Controls CO$_{2}$ Electrochemical Reduction. J. Phys. Chem. C 2015, 119, 20892–20899._x000d_ $^{4}$Rosen, B. A.; Zhu, W.; Kaul, G.; Salehi-Khojin, A.; Masel, R. I., Water Enhancement of CO$_{2}$ Conversion on Silver in 1-Ethyl-3-Methylimidazolium Tetrafluoroborate. J. Electrochem. Soc. 2013, 160, H138-H141._x000d_ _x000d_ _x000d_ _x000d_

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/96953

DOI

https://doi.org/10.15278/isms.2017.WE06

Copyright and License Information

Copyright 2017 Natalia Garcia Rey

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