Water vapor electron scattering cross-section measurements using a hydrophobic ionic liquid

Khalifa, Yehia; Broderick, Alicia; Newberg, John T.

doi:10.1016/j.elspec.2017.06.002

Cited by 6 publications

(7 citation statements)

References 39 publications

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“…Rivera-Rubero and Baldelli, for example, showed that water can be removed from the IL 1-butyl-3-methylimidazolium tetrafluoroborate ([C 4 C 1 Im][BF 4 ]) at pressures of <1 × 10 –5 mbar at room temperature . The recent availability of near-ambient pressure XPS (NAPXPS) has opened up the possibility of measurements of liquid surfaces in gas pressures of up to a few tens of mbar. ,,− In our own work and in works of groups such as the Newberg group, − NAPXPS has allowed for surface-sensitive studies of the interactions between gas molecules and ILs. Herein, we examine the reaction of the superbasic IL, [P 66614 ][benzim], with CO 2 , H 2 O, and two mixed CO 2 /H 2 O vapor regimes using NAPXPS.…”

Section: Introductionmentioning

confidence: 90%

Reversible Reaction of CO₂ with Superbasic Ionic Liquid [P₆₆₆₁₄][benzim] Studied with in Situ Photoelectron Spectroscopy

Henderson

Thomas²,

Wagstaffe³

et al. 2019

J. Phys. Chem. C

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Ionic liquids (ILs) are of significant interest as CO2 capture agents, and one subgroup of ILs that has shown particular promise is that of superbasic ILs. They can absorb large quantities of CO2 in the dry state, but some will have a diminished CO2 capacity when pre-wetted. In the work presented here, the superbasic IL trihexyl-tetradecylphosphonium benzimidazolide, or [P66614][benzim], was exposed to 3 mbar CO2, 2 mbar H2O vapor, and a CO2 + H2O gas mixture; and investigated using near-ambient pressure X-ray photoelectron spectroscopy. The results show that the IL reacts with CO2 to form carbamate, and that the reaction is reversible through reduction of the surrounding gas pressure. Regardless of whether the IL was exposed to CO2 or H2O vapor first, the presence of H2O under these experimental conditions does not significantly hinder the IL's ability to absorb and react with CO2. Furthermore, the IL appears to preferentially react with CO2 over H2O vapor.

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Section: Introductionmentioning

confidence: 90%

Reversible Reaction of CO₂ with Superbasic Ionic Liquid [P₆₆₆₁₄][benzim] Studied with in Situ Photoelectron Spectroscopy

Henderson

Thomas²,

Wagstaffe³

et al. 2019

J. Phys. Chem. C

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“…An Ag/AgCl is used as a QRE in order to appropriately control the WE. Recently, our group has utilized APXPS to examine IL/gas interfaces in the presence of water vapor [63–66] . Herein these studies are extended by examining the IL 1‐butyl‐3‐methyimidazolium acetate, [C 4 mim][OAc], as a function of water vapor pressure and external bias.…”

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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“…In the current study, we combine both AR-XPS and MD simulations to examine the IL–vacuum interface of the IL mixture [C 2 MIM][TFSI] 0.1 [OAc] 0.9 (where [OAc] − is acetate). Although IL–vacuum interfaces of pure ILs for imidazolium-based [TFSI] − and [OAc] − ILs have been examined via XPS ,,− and MD simulations, to our knowledge the surface structure of [TFSI] − mixed with [OAc] − has not been examined by XPS or MD. In this study, it will be shown that both AR-XPS and MD results yield a more significant enhancement of the [TFSI] − anion at the liquid/vacuum interface relative to the bulk, despite [TFSI] − having a significantly lower concentration in the bulk compared to [OAc] − and [C 2 mim] + .…”

Section: Introductionmentioning

confidence: 99%

Anion Enhancement at the Liquid–Vacuum Interface of an Ionic Liquid Mixture

et al. 2018

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The liquid−vacuum interface was investigated for a ionic liquid (IL) mixture containing 1-ethyl-3-methylimidazolium acetate, [C 2 MIM][OAc], and 1ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [C 2 MIM][TFSI]. Herein, we detail a quantitative connection between molecular simulations and angle-resolved X-ray photoemission spectroscopy for an IL−vacuum interface. Results show that for a mixture with a low concentration of [TFSI] − , the anion [OAc] − is slightly depleted from the interface, whereas the [TFSI] − anion is significantly enhanced relative to the bulk. Both experiments and simulations reveal that the mole fraction of [TFSI] − increases significantly from the bulk value in the top 17 Å. Furthermore, simulations show that [TFSI] − has a preferred orientation at the liquid−vacuum interface.

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Water vapor electron scattering cross-section measurements using a hydrophobic ionic liquid

Cited by 6 publications

References 39 publications

Reversible Reaction of CO₂ with Superbasic Ionic Liquid [P₆₆₆₁₄][benzim] Studied with in Situ Photoelectron Spectroscopy

Reversible Reaction of CO₂ with Superbasic Ionic Liquid [P₆₆₆₁₄][benzim] Studied with in Situ Photoelectron Spectroscopy

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

Anion Enhancement at the Liquid–Vacuum Interface of an Ionic Liquid Mixture

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Water vapor electron scattering cross-section measurements using a hydrophobic ionic liquid

Cited by 6 publications

References 39 publications

Reversible Reaction of CO2 with Superbasic Ionic Liquid [P66614][benzim] Studied with in Situ Photoelectron Spectroscopy

Reversible Reaction of CO2 with Superbasic Ionic Liquid [P66614][benzim] Studied with in Situ Photoelectron Spectroscopy

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

Anion Enhancement at the Liquid–Vacuum Interface of an Ionic Liquid Mixture

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Reversible Reaction of CO₂ with Superbasic Ionic Liquid [P₆₆₆₁₄][benzim] Studied with in Situ Photoelectron Spectroscopy

Reversible Reaction of CO₂ with Superbasic Ionic Liquid [P₆₆₆₁₄][benzim] Studied with in Situ Photoelectron Spectroscopy