In Situ X-ray Photoelectron Spectroscopic and Electrochemical Studies of the Bromide Anions Dissolved in 1-Ethyl-3-Methyl Imidazolium Tetrafluoroborate

Kruusma, Jaanus; Tõnisoo, Arvo; Pärna, Rainer; Nõmmiste, E.; Lust, Enn

doi:10.3390/nano9020304

Cited by 13 publications

(10 citation statements)

References 51 publications

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“…The ε(1s) method might also be useful when the changes in the XPS spectra upon variation of the chemical composition are a focus of study, for example, in studies of interfacial reactions. [ 15 ]…”

Section: Resultsmentioning

confidence: 99%

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Calculation of core‐level electron spectra of ionic liquids

Lembinen

Nõmmiste

Ers

et al. 2020

Int J of Quantum Chemistry

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On the example of 40 ion pairs (5 cations times 8 anions), this study demonstrates how the core-level binding energy values can be calculated and used to plot theoretical spectra at low computational cost using density functional theory methods. Three approaches for obtaining the binding energy values are based on delta Kohn-Sham (ΔKS) calculations, 1s KS orbital energies, and atomic charges. The ΔKS results show reasonable agreement with the available experimental X-ray photoelectron data. The 1s KS orbital energies correlate well with the ΔKS results. Atomic charge correlation with ΔKS is improved by accounting for the charges of neighboring atoms. Assignment of binding energies to atoms and the applicability of the mentioned methods to model systems of ionic liquids are discussed. K E Y W O R D S core-level binding energy, delta Kohn-Sham, Green function, ionic liquid, X-ray photoelectron spectra

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Section: Resultsmentioning

confidence: 99%

“…[ 8–13 ] The progress in UHV studies of ILs is remarkable; such studies provide essential insights into the behavior of ILs in the applied conditions. [ 13–15 ]…”

Section: Introductionmentioning

confidence: 99%

Calculation of core‐level electron spectra of ionic liquids

Lembinen

Nõmmiste

Ers

et al. 2020

Int J of Quantum Chemistry

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“…Facilitated by their high vacuum compatibility, over the past decade ILs have been fairly well characterized in‐vacuo by X‐ray photoelectron spectroscopy (XPS) as a function of electrochemical potential [34–58] . XPS allows for the determination of surface composition of an IL while also probing the binding energy shifts in the ions ( U XPS ; units of eV) as a function of an external electrochemical potential ( U ; units of V).…”

Section: Introductionmentioning

confidence: 99%

The Influence of Water Vapor on the Electrochemical Shift of an Ionic Liquid Measured by Ambient Pressure X‐ray Photoelectron Spectroscopy

2021

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Ionic liquids (ILs) are considered to be one of the steppingstones to fabricate next generation electrochemical devices given their unique physical and chemical properties. The addition of water to ILs significantly impact electrochemical related properties including viscosity, density, conductivity, and electrochemical window. Herein we utilize ambient pressure X‐ray photoelectron spectroscopy (APXPS) to examine the impact of water on values of the electrochemical shift (S), which is determined by measuring changes in binding energy shifts as a function of an external bias. APXPS spectra of C 1s, O 1s and N 1s regions are examined for the IL 1‐butyl‐3‐methylimidazolium acetate, [C4mim][OAc], at the IL/gas interface as a function of both water vapor pressure and external bias. Results reveal that in the absence of water vapor there is an IL ohmic drop between the working electrode and quasi reference electrode, giving rise to chemical specific S values of less than one. Upon introducing water vapor, S values approach one as a function of increasing water vapor pressure, indicating a decrease in the IL ohmic drop as the IL/water mixture becomes more conductive and the potential drop is driven by the electric double layer at the electrode/IL interface.

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“…It is composed by eight research articles, that together provide not only an interesting and multi-disciplinary overview on the chemico-physical investigation of nanostructured materials carried out by state-of-the-art synchrotron radiation induced techniques, but also an exciting glance on the future perspectives of nanomaterials characterization methods. The published papers focus on the chemical, structural, and morphological characterization of nanostructured materials of different nature carried out by a wide selection of SR-induced techniques such as the X-ray photoelectron spectroscopy (XPS) [1,2] and near edge X-ray absorption fine structure (NEXAFS) [1], in situ XPS and electrochemistry [3], time-resolved X-ray scattering [4], nuclear forward scattering (NFS) of synchrotron radiation [5], soft X-ray absorption spectroscopy (sXAS) [6], X-ray fluorescence [7], X-ray diffraction [7], X-ray absorption [7] and time-resolved X-ray transmission microscopy [8].…”

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confidence: 99%

“…The SR-induced XPS allowed the authors to observe that the down-dimer Ge atoms and the back-bonded subsurface atoms remained inert towards atomic O and molecular O 2 , a behavior which might account for the low reliability in the Ge-related metal-oxide-semiconductor (MOS) devices. Still using XPS, but in situ experimental conditions in the field of electrochemistry, J. Kruusma et al [3] investigated the influence of electrode potential on the electrochemical behavior of a 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF 4 ) solution containing 5 wt% 1-ethyl-3-methylimidazolium bromide (EMImBr). The authors followed the evolution of the Br 3d 5/2 XPS signal, collected in a 5 wt% EMImBr solution at an EMImBF 4 –vacuum interface, and were able to detect the start of the electrooxidation process of the Br − anion to Br 3− anion and thereafter to the Br 2 at the micro-mesoporous carbon electrode, polarized continuously at the high fixed positive potentials.…”

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confidence: 99%