Vibrational stark effect to probe the electric-double layer of the ionic liquid-metal electrodes

Garcia Rey, Natalia

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https://hdl.handle.net/2142/96960 Copy

Description

Title

Vibrational stark effect to probe the electric-double layer of the ionic liquid-metal electrodes

Author(s)

Garcia Rey, Natalia

Contributor(s)

• Dlott, Dana
• Toyouchi, Shuichi
• Moore, Alexander Knight

Issue Date

2017-06-20

Keyword(s)

Fundamental interest

Abstract

Vibrational sum frequency generation (VSFG) spectroscopy is used to study the effect of room temperature ionic liquids (RTILs) textit{in situ} at the electrical double layer (EDL). RTILs have been recognized as electrolytes without solvent for applications in batteries, supercapacitors and electrodeposition$^{1}$. The molecular response of the RTIL in the EDL affects the performance of these devices. We use the vibrational Stark effect on CO as a probe to detect the changes in the electric field affected by the RTIL across the EDL on metal electrodes. The Stark effect is a shift in the frequency in response to an externally applied electric field and also influenced by the surrounding electrolyte and electrode$^{2}$. The CO Stark shift is monitored by the CO-VSFG spectra on Pt or Ag in a range of different imidazolium-based RTILs electrolytes, where their composition is tuned by exchanging the anion, the cation or the imidazolium functional group. We study the free induction decay (FID)$^{3}$ of the CO to monitor how the RTIL structure and composition affect the vibrational relaxation of the CO. Combining the CO vibrational Stark effect and the FID allow us to understand how the RTIL electrochemical response, molecular orientation response and collective relaxation affect the potential drop of the electric field across the EDL, and, in turn, how determines the electrical capacitance or reactivity of the electrolyte/electrode interface._x000d_ _x000d_ _x000d_ $^{1}$Fedorov, M. V.; Kornyshev, A. A., Ionic Liquids at Electrified Interfaces. Chem. Rev. 2014, 114, 2978-3036._x000d_ _x000d_ $^{2}$ (a) Lambert, D. K., Vibrational Stark Effect of Adsorbates at Electrochemical Interfaces. Electrochim. Acta 1996, 41, 623-630. (b) Oklejas, V.; Sjostrom, C.; Harris, J. M., SERS Detection of the Vibrational Stark Effect from Nitrile-Terminated SAMs to Probe Electric Fields in the Diffuse Double-Layer. J. Am. Chem. Soc. 2002, 124, 2408-2409._x000d_ _x000d_ $^{3}$Symonds, J. P. R.; Arnolds, H.; Zhang, V. L.; Fukutani, K.; King, D. A.,Broadband Femtosecond Sum-Frequency Spectroscopy of CO on Ru{1010} in the Frequency and Time Domains. J. Chem. Phys. 2004, 120, 7158-7164._x000d_ _x000d_

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/96960

DOI

https://doi.org/10.15278/isms.2017.TE10

Copyright and License Information

Copyright 2017 Natalia Garcia Rey

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