VIBRATIONAL SUM FREQUENCY STUDY OF THE INFLUENCE OF WATER-IONIC LIQUID MIXTURES IN THE CO2 ELECTROREDUCTION ON SILVER ELECTRODES

Garcia-Rey, Natalia

Permalink

https://hdl.handle.net/2142/79343 Copy

Description

Title

VIBRATIONAL SUM FREQUENCY STUDY OF THE INFLUENCE OF WATER-IONIC LIQUID MIXTURES IN THE CO2 ELECTROREDUCTION ON SILVER ELECTRODES

Author(s)

Garcia-Rey, Natalia

Contributor(s)

Dlott, Dana

Issue Date

26-Jun-15

Keyword(s)

Spectroscopy as an analytical tool

Abstract

Understand the molecular dynamics on buried electrodes under electrochemical transformations is of significant interest. There is a big gap of knowledge in the CO$_{2}$ electroreduction mechanism due to the limitations to access and probe the liquid-metal interfaces [1,2]. Vibrational Sum Frequency Spectroscopy (VSFS) is a non-invasive and surface sensitive technique, with molecular level detection that can be used to probe electrochemical reactions occurring on the electrolyte-electrode interface [2]. We observed the CO$_{2}$ electroreduction to CO in ionic liquids (ILs) on poly Ag using VSFS synchronized with cyclic voltammetry. In order to follow the CO$_{2}$ reaction in situ on the ionic liquid-Ag interface; the CO, CO$_{2}$ and imidazolium vibrational modes (resonant SFS) were monitored as a function of potential. We identified at which potential the CO was produced and how the EMIM-BF$_{4}$ played an important role in the electron transfer to the CO$_{2}$, lowering the CO$_{2}^{-}$ energy barrier. A new approach to reveal the double layer dynamics to the electrostatic environment is presented by the study of the nonresonant sum frequency intensity as a function of the applied potential. By this method, we studied the influence of water-ionic liquid mixtures in the CO$_{2}$ electroreduction on Ag electrode. We observed a shift to lower potentials in the CO$_{2}$ electroreduction in water-ILs electrolyte. Previous studies in gas diffusion fuel cells have shown the CO$_{2}$ electroreduction in a water-imidazolium�based ILs on Ag nanoparticles at lower overpotential [3]. Our VSFS study helps to understand the fundamental electrochemical mechanism, showing how the ILs structural transition influences the CO$_{2}$ electroreduction. [1] Polyansky, D. E.; Electroreduction of Carbon Dioxide, 2014, Encyclopedia of Applied Electrochemistry, Springer New York, pag 431-437. [2] Bain, C. D.; J. Chem. Soc., Faraday Trans., 1995, 91, 1281. [3] Rosen, B. A. et al; Science, 2011, 334 (6056), 643. Rosen, B. A. et al.; J. electrochem. Soc., 2013, 160 (2), H138.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/79343

Owning Collections