1
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Mayer S, Bergen A, Zhai Z, Trzeciak S, Chu J, Zahn D, Koller TM, Meyer K, Vogel N. Evolution of Surface Tension and Hansen Parameters of a Homologous Series of Imidazolium-Based Ionic Liquids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:9529-9542. [PMID: 38648374 DOI: 10.1021/acs.langmuir.4c00094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
In this study, we systematically analyze the surface tension and Hansen solubility parameters (HSPs) of imidazolium-based ionic liquids (ILs) with different anions ([NTf2]-, [PF6]-, [I]-, and [Br]-). These anions are combined with the classical 1-alkyl-3-methyl-substituted imidazolium cations ([CnC1Im]+) and a group of oligoether-functionalized imidazolium cations ([(mPEGn)2Im]+) based on methylated polyethylene glycol (mPEGn). In detail, the influences of the length of the alkyl- and the mPEGn-chain, the anion size, and the water content are investigated experimentally. For [CnC1Im]+-based ILs, the surface tension decreases with increasing alkyl chain length in all cases, but the magnitude of this decrease depends on the size of the anion ([NTf2]- < [PF6]- < [Br]- ≤ [I]-). Molecular dynamics (MD) simulations on [CnC1Im]+-based ILs indicate that these differences are caused by the interplay of charged and uncharged domains, in particular in the different anions, which affects the ability of the alkyl chains of the cation to orient toward the liquid-gas interface. An increase in the mPEGn-chain length of the [(mPEGn)2Im][A] ILs does not significantly influence the surface tension. These changes upon variation of the cation/anion combination do not correlate with the evolution of the HSPs for the two sets of ILs. Finally, our data suggest that significant water contents up to water mole fractions of x(H2O) = 0.25 do not significantly affect the surface tension of the studied binary IL-water mixtures.
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Affiliation(s)
- Sophie Mayer
- Institute of Particle Technology, Department of Chemical and Biological Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058 Erlangen, Germany
| | - Alexander Bergen
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr.1, 91058 Erlangen, Germany
| | - Ziwen Zhai
- Institute of Advanced Optical Technologies─Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering and Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Paul-Gordan-Str. 8, 91052 Erlangen, Germany
| | - Simon Trzeciak
- Computer Chemistry Center/Theoretical Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Nägelsbachstr. 25, 91052 Erlangen, Germany
| | - Junyu Chu
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr.1, 91058 Erlangen, Germany
| | - Dirk Zahn
- Computer Chemistry Center/Theoretical Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Nägelsbachstr. 25, 91052 Erlangen, Germany
| | - Thomas M Koller
- Institute of Advanced Optical Technologies─Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering and Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Paul-Gordan-Str. 8, 91052 Erlangen, Germany
| | - Karsten Meyer
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr.1, 91058 Erlangen, Germany
| | - Nicolas Vogel
- Institute of Particle Technology, Department of Chemical and Biological Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058 Erlangen, Germany
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2
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Duwadi A, Baldelli S. Evidence for Ion Association at the Gas-Liquid Interface of the Mixture of 1-Butyl-3-methylimidazolium Hexafluorophosphate and Benzonitrile: A Sum Frequency Generation Spectroscopy and Surface Tension Study. J Phys Chem B 2023; 127:3496-3504. [PMID: 37023246 DOI: 10.1021/acs.jpcb.3c01793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
The gas-liquid interface for the mixtures of [BMIM][PF6] and benzonitrile is studied by sum frequency generation (SFG) spectroscopy and surface tension measurements as an important solute to reduce the viscosity of ionic liquids. Solvation of ionic compounds in bulk solvent is not necessarily the same as that at the surface due to the lower dielectric medium at the air/liquid interface. The results from the temperature-dependent SFG spectroscopy and surface tension study suggest that the ionic liquid in a benzonitrile solvent is associated as ion pairs at the surface rather than as dissociated─solvated─ions in the bulk solution. The influence of ionic liquids on the surface structure of benzonitrile is investigated from 0 to 1.0 mole fraction of benzonitrile. The CH stretching mode of vibration of benzonitrile in the SFG spectrum begins from a 0.2 mole fraction (x) of benzonitrile, and the intensity of the peak constantly increases on increasing the concentration of benzonitrile. However, the addition of benzonitrile does not result in extra peaks or shifting of the peak frequency to the spectra of [BMIM][PF6]. The surface tension measurements further support the presence of benzonitrile at the gas-liquid interface. The surface tension data of the mixture smoothly decrease as the benzonitrile concentration increases. The apparent tilt angle of the terminal methyl group of the cation of [BMIM][PF6] is calculated from SFG polarization spectra and shows an apparent lowering with the addition of benzonitrile. The effect of temperature on the surface structure of the binary mixture is also reported at four different temperatures between -15 and 40 °C for both the SFG spectroscopy and surface tension study. Benzonitrile shows different behavior in the mixture at higher temperatures than pure benzonitrile, as observed in the SFG spectra. In contrast, it does not show any CN peak in the mixture below 0.9 mole fraction. The temperature dependence of the interfacial tension is used to evaluate thermodynamic functions such as surface entropy and surface enthalpy. Both were found to be lowered with the increasing concentration of benzonitrile. Both spectroscopic and thermodynamic analyses indicate that the ionic liquid is highly associated as ion pairs and the benzonitrile is more ordered at the surface at concentration <0.4×.
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Affiliation(s)
- Anjeeta Duwadi
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
| | - Steven Baldelli
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
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3
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Ibrahim S, Ntomprougkidis V, Goutte M, Monier G, Traïkia M, Andanson JM, Bonnet P, Bousquet A. Reactive sputtering onto an ionic liquid, a new synthesis route for bismuth-based nanoparticles. NANOSCALE 2023; 15:5499-5509. [PMID: 36853235 DOI: 10.1039/d2nr07028f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Metallic bismuth and Bi-oxyfluoride nanoparticles (NPs) are successfully synthesized by non-reactive and reactive sputtering of a Bi target onto 1-butyl-3-methylimidazolium bis(trifluoro-methylsulfonyl)imide ([BMIM][TFSI]) ionic liquid (IL). Non-reactive sputtering is realized in pure Ar plasma, where isotropic, well crystallized and dispersed Bi NPs of 3-7 nm are obtained. The diameter and the size distribution of these NPs do not significantly vary with the power, gas pressure, and sputtering time; but these sputtering parameters seem to influence the NP concentration. Then, the introduction of O2 and CF4 gases in addition to Ar enables the reaction of radicals from plasma with Bi clusters at the liquid's top surface to form Bi-oxyfluoride NPs of 3-12 nm in diameter with photocatalytic activity. Hence, the reactive sputtering onto an IL is an efficient, original and promising method for synthesizing Bi-based compound NPs. Finally, we propose a mechanism based on reactions of species from plasma at the IL surface to explain the formation of Bi-compounds by reactive sputtering.
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Affiliation(s)
- Sara Ibrahim
- Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France.
| | - Vitalios Ntomprougkidis
- Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France.
| | - Mathias Goutte
- Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France.
| | - Guillaume Monier
- Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut Pascal, F-63000 Clermont-Ferrand, France
| | - Mounir Traïkia
- Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France.
| | - Jean-Michel Andanson
- Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France.
| | - Pierre Bonnet
- Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France.
| | - Angelique Bousquet
- Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France.
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Matsumoto Y. Recent Progress in Vacuum Engineering of Ionic Liquids. Molecules 2023; 28:1991. [PMID: 36838981 PMCID: PMC9966320 DOI: 10.3390/molecules28041991] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
Since the discovery of ionic liquids (ILs) as a new class of liquid that can survive in a vacuum at room temperature, they have been aimed at being characterized with vacuum analysis techniques and used in vacuum processes for the last two decades. In this review, our state-of-the-art of the vacuum engineering of ILs will be introduced. Beginning with nanoscale vacuum deposition of IL films and their thickness-dependent ionic conductivity, there are presented some new applications of the ellipsometry to in situ monitoring of the thickness of IL films and their glass transitions, and of the surface thermal fluctuation spectroscopy to investigation of the rheological properties of IL films. Furthermore, IL-VLS (vapor-liquid-solid) growth, a vacuum deposition via IL, has been found successful, enhancing the crystallinity of vacuum-deposited crystals and films, and sometimes controlling their surface morphology and polymorphs. Among recent applications of ILs are the use of metal ions-containing IL and thin film nano IL gel. The former is proposed as a low temperature evaporation source of metals, such as Ta, in vacuum deposition, while the latter is demonstrated to work as a gate electrolyte in an electric double layer organic transistor.
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Affiliation(s)
- Yuji Matsumoto
- Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aramaki-Aza-Aoba, Aoba-ku, Sendai 980-8579, Japan
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Hemmeter D, Kremitzl D, Schulz PS, Wasserscheid P, Maier F, Steinrück HP. The Buoy Effect: Surface Enrichment of a Pt Complex in IL Solution by Ligand Design. Chemistry 2023; 29:e202203325. [PMID: 36446030 PMCID: PMC10107114 DOI: 10.1002/chem.202203325] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 11/30/2022]
Abstract
The targeted enrichment of a Pt complex with an ionic liquid (IL)-derived ligand system in IL solution is demonstrated by using angle-resolved X-ray photoelectron spectroscopy. When the ligand system is complemented with fluorinated side chains, the complex accumulates strongly at the IL/gas interface, while in an equivalent solution of a complex without these substituents no such effect could be observed. This buoy-like behavior induces strong population of the complex at the outermost molecular layer close to surface saturation, which was studied over a range from 5 to 30 %mol . The surface enrichment was found to be most efficient at the lowest concentration, which is particularly favorable for catalytic applications such as supported ionic-liquid-phase (SILP) catalysis.
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Affiliation(s)
- Daniel Hemmeter
- Lehrstuhl für Physikalische Chemie 2, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Daniel Kremitzl
- Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Peter S Schulz
- Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Peter Wasserscheid
- Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany.,Forschungszentrum Jülich GmbH, Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Egerlandstr. 3, 91058, Erlangen, Germany
| | - Florian Maier
- Lehrstuhl für Physikalische Chemie 2, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Hans-Peter Steinrück
- Lehrstuhl für Physikalische Chemie 2, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
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Li J, Jin Y, Rinke P, Yang W, Golze D. Benchmark of GW Methods for Core-Level Binding Energies. J Chem Theory Comput 2022; 18:7570-7585. [PMID: 36322136 PMCID: PMC9753590 DOI: 10.1021/acs.jctc.2c00617] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The GW approximation has recently gained increasing attention as a viable method for the computation of deep core-level binding energies as measured by X-ray photoelectron spectroscopy. We present a comprehensive benchmark study of different GW methodologies (starting point optimized, partial and full eigenvalue-self-consistent, Hedin shift, and renormalized singles) for molecular inner-shell excitations. We demonstrate that all methods yield a unique solution and apply them to the CORE65 benchmark set and ethyl trifluoroacetate. Three GW schemes clearly outperform the other methods for absolute core-level energies with a mean absolute error of 0.3 eV with respect to experiment. These are partial eigenvalue self-consistency, in which the eigenvalues are only updated in the Green's function, single-shot GW calculations based on an optimized hybrid functional starting point, and a Hedin shift in the Green's function. While all methods reproduce the experimental relative binding energies well, the eigenvalue self-consistent schemes and the Hedin shift yield with mean absolute errors <0.2 eV the best results.
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Affiliation(s)
- Jiachen Li
- Department
of Chemistry, Duke University, Durham, North Carolina27708, United States
| | - Ye Jin
- Department
of Chemistry, Duke University, Durham, North Carolina27708, United States
| | - Patrick Rinke
- Department
of Applied Physics, Aalto University, Otakaari 1, FI-02150Espoo, Finland
| | - Weitao Yang
- Department
of Chemistry, Duke University, Durham, North Carolina27708, United States
| | - Dorothea Golze
- Department
of Applied Physics, Aalto University, Otakaari 1, FI-02150Espoo, Finland,Faculty
of Chemistry and Food Chemistry, Technische
Universität Dresden, 01062Dresden, Germany,
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7
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Li J, Yang W. Renormalized Singles with Correlation in GW Green's Function Theory for Accurate Quasiparticle Energies. J Phys Chem Lett 2022; 13:9372-9380. [PMID: 36190273 DOI: 10.1021/acs.jpclett.2c02051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We apply the renormalized singles with the correlation (RSc) Green function in the GW approximation for accurate quasiparticle (QP) energies and orbitals. The RSc Green function includes singles contributions from the associated density functional approximation (DFA) and considers correlation contributions perturbatively. GRScWRSc uses the RSc Green function as the new starting point and in the formulation of the screened interaction. GRScW0 fixes the screened interaction at the DFA level. For the calculations of ionization potentials, GRScWRSc and GRScW0 significantly reduce the starting point dependence and provide accurate results with errors around 0.2 eV. For the calculations of core-level binding energies, GRScWRSc slightly overestimates the results because of underscreening, but GRScW0 with GGA functionals provides the optimal accuracy with errors of 0.40 eV. We also show that GRScWRSc predicts accurate dipole moments. GRScWRSc and GRScW0, are computationally favorable compared with any self-consistent GW methods. The RSc approach is promising for making GW and other Green function methods efficient and robust.
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Affiliation(s)
- Jiachen Li
- Department of Chemistry, Duke University, Durham, North Carolina27708, United States
| | - Weitao Yang
- Department of Chemistry, Duke University, Durham, North Carolina27708, United States
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8
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Ishisone K, Ori G, Boero M. Structural, dynamical, and electronic properties of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. Phys Chem Chem Phys 2022; 24:9597-9607. [PMID: 35403652 DOI: 10.1039/d2cp00741j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We provide a microscopic insight, both structural and electronic, into the multifold interactions occurring in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIM][TFSI] currently targeted for applications in next-generation low-power electronics and optoelectronic devices. To date, practical applications have remained hampered by the lack of fundamental understanding of the interactions occurring both inside the IL and at the interface with the substrate. Our first principles dynamical simulations provide accurate insights into the nature of bonding and non-bonding interactions, dynamical conformational changes and induced dipole moments, along with their statistical distributions, of this ionic liquid, that have so far not been completely unraveled. The mobilities of the two ionic species are obtained by long-lasting dynamical simulations at finite temperature, allowing simultaneous monitoring and quantification of the isomerization occurring in the IL. Moreover, a thorough analysis of the electronic structure and partial charge distributions characterizing the two components, the cation and anion, allow rationalization of the nature of the electrostatic interactions, hydrogen bonding properties of the two ionic counterparts, and the infra-red and dielectric response of the system, especially in the low frequency range, for the full characterization of the IL.
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Affiliation(s)
- Kana Ishisone
- University of Strasbourg, Institut de Physique et Chimie des Matériaux de Strasbourg, CNRS, UMR 7504, 23 rue du Loess, F-67034, France.
| | - Guido Ori
- University of Strasbourg, Institut de Physique et Chimie des Matériaux de Strasbourg, CNRS, UMR 7504, 23 rue du Loess, F-67034, France.
| | - Mauro Boero
- University of Strasbourg, Institut de Physique et Chimie des Matériaux de Strasbourg, CNRS, UMR 7504, 23 rue du Loess, F-67034, France.
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9
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Du Hill L, De Keersmaecker M, Colbert AE, Hill JW, Placencia D, Boercker JE, Armstrong NR, Ratcliff EL. Rationalizing energy level alignment by characterizing Lewis acid/base and ionic interactions at printable semiconductor/ionic liquid interfaces. MATERIALS HORIZONS 2022; 9:471-481. [PMID: 34859805 DOI: 10.1039/d1mh01306h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Charge transfer and energy conversion processes at semiconductor/electrolyte interfaces are controlled by local electric field distributions, which can be especially challenging to measure. Herein we leverage the low vapor pressure and vacuum compatibility of ionic liquid electrolytes to undertake a layer-by-layer, ultra-high vacuum deposition of a prototypical ionic liquid EMIM+ (1-ethyl-3-methylimidazolium) and TFSI- (bis(trifluoromethylsulfonyl)-imide) on the surfaces of different electronic materials. We consider a case-by-case study between a standard metal (Au) and four printed electronic materials, where interfaces are characterized by a combination of X-ray and ultraviolet photoemission spectroscopies (XPS/UPS). For template-stripped gold surfaces, we observe through XPS a preferential orientation of the TFSI anion at the gold surface, enabling large electric fields (∼108 eV m-1) within the first two monolayers detected by a large surface vacuum level shift (0.7 eV) in UPS. Conversely, we observe a much more random orientation on four printable semiconductor surfaces: methyl ammonium lead triiodide (MAPbI3), regioregular poly(3-hexylthiophene-2,5-diyl (P3HT)), sol-gel nickel oxide (NiOx), and PbIx-capped PbS quantum dots. For the semiconductors considered, the ionization energy (IE) of the ionic liquid at 3 ML coverage is highly substrate dependent, indicating that underlying chemical reactions are dominating interface level alignment (electronic equilibration) prior to reaching bulk electronic structure. This indicates there is no universal rule for energy level alignment, but that relative strengths of Lewis acid/base sites and ion-molecular interactions should be considered. Specifically, for P3HT, interactions are found to be relatively weak and occurring through the π-bonding structure in the thiophene ring. Alternatively, for NiOx, PbS/PbIx quantum dots, and MAPbI3, our XPS data suggest a combination of ionic bonding and Lewis acid/base reactions between the semiconductor and IL, with MAPbI3 being the most reactive surface. Collectively, our results point towards new directions in interface engineering, where strategically chosen ionic liquid-based anions and cations can be used to preferentially passivate and/or titrate surface defects of heterogeneous surfaces while simultaneously providing highly localized electric fields. These opportunities are expected to be translatable to opto-electronic and electrochemical devices, including energy conversion and storage and biosensing applications.
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Affiliation(s)
- Linze Du Hill
- Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721, USA.
| | - Michel De Keersmaecker
- Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721, USA.
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E. University Blvd., Tucson, AZ 85721, USA
| | - Adam E Colbert
- US. Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC. 20375, USA
| | - Joshua W Hill
- Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721, USA.
| | - Diogenes Placencia
- US. Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC. 20375, USA
| | - Janice E Boercker
- US. Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC. 20375, USA
| | - Neal R Armstrong
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E. University Blvd., Tucson, AZ 85721, USA
| | - Erin L Ratcliff
- Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721, USA.
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E. University Blvd., Tucson, AZ 85721, USA
- Department of Materials Science and Engineering, University of Arizona, 1235 E. James E. Rogers Way, Tucson, AZ 85721, USA
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10
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Tanabe I. Spectroscopic analysis focusing on ionic liquid/metal electrode and organic semiconductor interfaces in an electrochemical environment. Phys Chem Chem Phys 2021; 24:615-623. [PMID: 34853835 DOI: 10.1039/d1cp04094d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The solid-liquid interface forms an electric double layer that enables the function of electronic devices and, thus, represents an important area of electrochemical research. Because ionic liquids (ILs) are becoming prominent candidates for new high-performing electrolytes, their interface with solid substrates (e.g., metal electrodes or organic semiconductors) attracts substantial attention. An example of improvement achieved using ILs as electrolytes is a decrease in the operating voltage of transistors from >10 V in traditional SiO2-gated transistors to <1 V in IL-gated electronic double-layer organic field-effect devices. This perspective discusses the investigation of poorly accessible IL/substrate interfaces using both attenuated total reflectance ultraviolet (ATR-UV) spectroscopy and a newly developed electrochemical setup combined with ATR-UV (EC-ATR-UV), which allows analysis of the interfacial area under the application of varying electric potential. The recent EC-ATR-UV applications in interfacial analytical chemistry are overviewed and compared to other spectroscopic methods described in the recent literature. Lastly, the supplementation of experimental data with theoretical calculations (e.g., quantum chemical calculations and molecular dynamics simulations) is also addressed.
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Affiliation(s)
- Ichiro Tanabe
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
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11
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Hohner C, Fromm L, Schuschke C, Taccardi N, Xu T, Wasserscheid P, Görling A, Libuda J. Adsorption Motifs and Molecular Orientation at the Ionic Liquid/Noble Metal Interface: [C 2C 1Im][NTf 2] on Pt(111). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:12596-12607. [PMID: 34661413 DOI: 10.1021/acs.langmuir.1c01900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In solid catalysts with ionic liquid layers (SCILLs), ionic liquid (IL) thin films are used to modify the activity and selectivity of catalytic materials. In this work, we investigated the adsorption behavior of the IL 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [C2C1Im][NTf2] on Pt(111) by combining experimental and theoretical studies. Under ultrahigh vacuum (UHV) conditions, the IL was deposited onto a Pt(111) single crystal surface by physical vapor deposition (PVD) at different surface temperatures (200, 300, and 400 K). The adsorption process was monitored by in situ infrared reflection absorption spectroscopy (IRAS). Complementary to the IRAS studies, we performed density functional theory (DFT) calculations and analyzed the adsorption motifs and orientation of the IL ions. In total, we calculated four different systems: (a) [C2C1Im]+ and [NTf2]- ions in the gas phase; [NTf2]- anions in (b) small (4 × 4) and (c) large (6 × 6) Pt(111) supercells; and (d) a complete ion pair of [C2C1Im][NTf2] in a (6 × 6) Pt(111) supercell. Based on DFT, we simulated IR spectra and compared them to the experimental data. Our results suggest that the binding motif and orientation of the IL is strongly dependent on the actual IL coverage. In the monolayer (ML), [NTf2]- interacts strongly with the metal surface and adopts a specific orientation in which it interacts with the Pt surface via the SO2 groups. Also the [C2C1Im]+ cations adopt a preferential orientation up to coverages of 1 ML. Upon transition to the multilayer region, the specific orientation of the ions is gradually lost.
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Affiliation(s)
- Chantal Hohner
- Interface Research and Catalysis, Erlangen Center for Interface Research and Catalysis, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Lukas Fromm
- Lehrstuhl für Theoretische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Christian Schuschke
- Interface Research and Catalysis, Erlangen Center for Interface Research and Catalysis, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Nicola Taccardi
- Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Tao Xu
- Interface Research and Catalysis, Erlangen Center for Interface Research and Catalysis, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Peter Wasserscheid
- Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Andreas Görling
- Lehrstuhl für Theoretische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Jörg Libuda
- Interface Research and Catalysis, Erlangen Center for Interface Research and Catalysis, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
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12
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Seymour JM, Gousseva E, Large AI, Clarke CJ, Licence P, Fogarty RM, Duncan DA, Ferrer P, Venturini F, Bennett RA, Palgrave RG, Lovelock KRJ. Experimental measurement and prediction of ionic liquid ionisation energies. Phys Chem Chem Phys 2021; 23:20957-20973. [PMID: 34545382 DOI: 10.1039/d1cp02441h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ionic liquid (IL) valence electronic structure provides key descriptors for understanding and predicting IL properties. The ionisation energies of 60 ILs are measured and the most readily ionised valence state of each IL (the highest occupied molecular orbital, HOMO) is identified using a combination of X-ray photoelectron spectroscopy (XPS) and synchrotron resonant XPS. A structurally diverse range of cations and anions were studied. The cation gave rise to the HOMO for nine of the 60 ILs presented here, meaning it is energetically more favourable to remove an electron from the cation than the anion. The influence of the cation on the anion electronic structure (and vice versa) were established; the electrostatic effects are well understood and demonstrated to be consistently predictable. We used this knowledge to make predictions of both ionisation energy and HOMO identity for a further 516 ILs, providing a very valuable dataset for benchmarking electronic structure calculations and enabling the development of models linking experimental valence electronic structure descriptors to other IL properties, e.g. electrochemical stability. Furthermore, we provide design rules for the prediction of the electronic structure of ILs.
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Affiliation(s)
- Jake M Seymour
- Department of Chemistry, University of Reading, Reading, RG6 6AD, UK.
| | | | - Alexander I Large
- Department of Chemistry, University of Reading, Reading, RG6 6AD, UK. .,Diamond Light Source, Didcot, Oxfordshire, OX11 0DE, UK
| | - Coby J Clarke
- School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Peter Licence
- School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK
| | | | | | - Pilar Ferrer
- Diamond Light Source, Didcot, Oxfordshire, OX11 0DE, UK
| | | | - Roger A Bennett
- Department of Chemistry, University of Reading, Reading, RG6 6AD, UK.
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13
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Sedlak P, Sobola D, Gajdos A, Dallaev R, Nebojsa A, Kubersky P. Surface Analyses of PVDF/NMP/[EMIM][TFSI] Solid Polymer Electrolyte. Polymers (Basel) 2021; 13:polym13162678. [PMID: 34451218 PMCID: PMC8401855 DOI: 10.3390/polym13162678] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/05/2021] [Accepted: 08/09/2021] [Indexed: 11/17/2022] Open
Abstract
Thermal treatment conditions of solid polymer polymer electrolyte (SPE) were studied with respect to their impact on the surface morphology, phase composition and chemical composition of an imidazolium ionic-liquid-based SPE, namely PVDF/NMP/[EMIM][TFSI] electrolyte. These investigations were done using scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry as well as X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy. A thoroughly mixed blend of polymer matrix, ionic liquid and solvent was deposited on a ceramic substrate and was kept at a certain temperature for a specific time in order to achieve varying crystallinity. The morphology of all the electrolytes consists of spherulites whose average diameter increases with solvent evaporation rate. Raman mapping shows that these spherulites have a semicrystalline structure and the area between them is an amorphous region. Analysis of FTIR spectra as well as Raman spectroscopy showed that the β-phase becomes dominant over other phases, while DSC technique indicated decrease of crystallinity as the solvent evaporation rate increases. XPS and ToF-SIMS indicated that the chemical composition of the surface of the SPE samples with the highest solvent evaporation rate approaches the composition of the ionic liquid.
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Affiliation(s)
- Petr Sedlak
- Faculty of Electrical Engineering and Communications, Brno University of Technology, Technicka 10, 616 00 Brno, Czech Republic; (D.S.); (A.G.); (R.D.)
- Correspondence: ; Tel.: +420-54114-6021
| | - Dinara Sobola
- Faculty of Electrical Engineering and Communications, Brno University of Technology, Technicka 10, 616 00 Brno, Czech Republic; (D.S.); (A.G.); (R.D.)
- Institute of Physics of Materials, Academy of Sciences CR, Zizkova 22, 616 62 Brno, Czech Republic
| | - Adam Gajdos
- Faculty of Electrical Engineering and Communications, Brno University of Technology, Technicka 10, 616 00 Brno, Czech Republic; (D.S.); (A.G.); (R.D.)
| | - Rashid Dallaev
- Faculty of Electrical Engineering and Communications, Brno University of Technology, Technicka 10, 616 00 Brno, Czech Republic; (D.S.); (A.G.); (R.D.)
| | - Alois Nebojsa
- Central European Institute of Technology (CEITEC), Brno University of Technology, Purkynova 123, 612 00 Brno, Czech Republic;
| | - Petr Kubersky
- Research and Innovation Centre for Electrical Engineering (RICE), Faculty of Electrical Engineering, University of West Bohemia, Univerzitni 8, 301 00 Plzen, Czech Republic;
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14
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Kuusik I, Kook M, Pärna R, Kisand V. Ionic Liquid Vapors in Vacuum: Possibility to Derive Anodic Stabilities from DFT and UPS. ACS OMEGA 2021; 6:5255-5265. [PMID: 33681566 PMCID: PMC7931180 DOI: 10.1021/acsomega.0c05369] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/29/2021] [Indexed: 05/28/2023]
Abstract
Ultraviolet photoelectron spectroscopy (UPS) investigations of several gas-phase ionic liquid (IL) ion pairs have been conducted. [EMIM][OTF], [PYR14][OTF], [EMIM][DCA], [PYR14][DCA], [PYR14][TCM], [PYR14][FSI], [PYR14][PF6], [S222][TFSI], [P4441][TFSI], and [EMMIM][TFSI] vapor UPS spectra are presented for the first time. The experimental low-binding-energy cutoff value (highest occupied molecular orbital, HOMO energy) of the ionic liquid ion pairs, which is of great interest, has been measured. Many studies use calculated gas-phase electronic properties to estimate the liquid-phase electrochemical stability. Hybrid density functional theory (DFT) calculations have been used to interpret the experimental data. The gas-phase photoelectron spectra in conjunction with the theoretical calculations are able to verify most HOMO energies and assign them to the cation or anion. The hybrid M06 functional is shown to offer a very good description of the ionic liquid electronic structure. In some cases, the excellent agreement between the UPS spectra and the M06 calculation validates the conformer found and constitutes as a first indirect experimental determination of ionic liquid ion-pair structure. Comparisons with recent theoretical studies are made, and implications for electrochemical applications are discussed. The new data provide a much-needed reference for future ab initio calculations and support the argument that modeling of IL cations and anions separately is incorrect.
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Affiliation(s)
- Ivar Kuusik
- Institute of Physics, University of Tartu, W. Ostwaldi 1, EE-50411 Tartu, Estonia
| | - Mati Kook
- Institute of Physics, University of Tartu, W. Ostwaldi 1, EE-50411 Tartu, Estonia
| | - Rainer Pärna
- Institute of Physics, University of Tartu, W. Ostwaldi 1, EE-50411 Tartu, Estonia
| | - Vambola Kisand
- Institute of Physics, University of Tartu, W. Ostwaldi 1, EE-50411 Tartu, Estonia
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15
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Rangan S, Viereck J, Bartynski RA. Electronic Properties of Cyano Ionic Liquids: a Valence Band Photoemission Study. J Phys Chem B 2020; 124:7909-7917. [DOI: 10.1021/acs.jpcb.0c06423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sylvie Rangan
- Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
| | - Jonathan Viereck
- Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
| | - Robert A. Bartynski
- Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
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16
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Greco F, Shin S, Williams FJ, Heller BSJ, Maier F, Steinrück H. Potential Screening at Electrode/Ionic Liquid Interfaces from In Situ X-ray Photoelectron Spectroscopy. ChemistryOpen 2019; 8:1365-1368. [PMID: 31844602 PMCID: PMC6892450 DOI: 10.1002/open.201900211] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Indexed: 11/12/2022] Open
Abstract
A new approach to investigate potential screening at the interface of ionic liquids (ILs) and charged electrodes in a two-electrode electrochemical cell by in situ X-ray photoelectron spectroscopy has been introduced. Using identical electrodes, we deduce the potential screening at the working and the counter electrodes as a function of applied voltage from the potential change of the bulk IL, as derived from corresponding core level binding energy shifts for different IL/electrode combinations. For imidazolium-based ILs and Pt electrodes, we find a significantly larger potential screening at the anode than at the cathode, which we attribute to strong attractive interactions between the imidazolium cation and Pt. In the absence of specific ion/electrode interactions, asymmetric potential screening only occurs for ILs with different cation and anion sizes as demonstrated for an imidazolium chloride IL and Au electrodes, which we assign to the different thicknesses of the electrical double layers. Our results imply that potential screening in ILs is mainly established by a single layer of counterions at the electrode.
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Affiliation(s)
- Francesco Greco
- Lehrstuhl für Physikalische Chemie 2Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Sunghwan Shin
- Lehrstuhl für Physikalische Chemie 2Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Federico J. Williams
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, INQUIMAE-CONICETUniversidad de Buenos Aires, Ciudad UniversitariaPabellón 2Buenos AiresC1428EHAArgentina
| | - Bettina S. J. Heller
- Lehrstuhl für Physikalische Chemie 2Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Florian Maier
- Lehrstuhl für Physikalische Chemie 2Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Hans‐Peter Steinrück
- Lehrstuhl für Physikalische Chemie 2Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
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17
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Kuusik I, Kook M, Pärna R, Kivimäki A, Käämbre T, Reisberg L, Kikas A, Kisand V. The electronic structure of ionic liquids based on the TFSI anion: A gas phase UPS and DFT study. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Kim J, Weber I, Buchner F, Schnaidt J, Behm RJ. Surface chemistry and electrochemistry of an ionic liquid and lithium on Li4Ti5O12(111)—A model study of the anode|electrolyte interface. J Chem Phys 2019; 151:134704. [DOI: 10.1063/1.5119765] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jihyun Kim
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, D-89081 Ulm, Germany
| | - Isabella Weber
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, D-89081 Ulm, Germany
- Helmholtz Institute Ulm Electrochemical Energy Storage (HIU), Helmholtzstraße 11, D-89081 Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, D-76021 Karlsruhe, Germany
| | - Florian Buchner
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, D-89081 Ulm, Germany
| | - Johannes Schnaidt
- Helmholtz Institute Ulm Electrochemical Energy Storage (HIU), Helmholtzstraße 11, D-89081 Ulm, Germany
- Karlsruhe Institute of Technology (KIT), P.O. Box 3640, D-76021 Karlsruhe, Germany
| | - R. Jürgen Behm
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, D-89081 Ulm, Germany
- Helmholtz Institute Ulm Electrochemical Energy Storage (HIU), Helmholtzstraße 11, D-89081 Ulm, Germany
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19
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Lefebvre J, Galli F, Bianchi CL, Patience GS, Boffito DC. Experimental methods in chemical engineering: X‐ray photoelectron spectroscopy‐XPS. CAN J CHEM ENG 2019. [DOI: 10.1002/cjce.23530] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Josianne Lefebvre
- Department of Engineering PhysicsPolytechnique MontréalC.P. 6079, Succ. CV Montréal, QC, H3C 3A7 Canada
| | - Federico Galli
- Dipartimento di ChimicaUniversitá degli Studi di Milanovia Golgi 19, 20133 Milano Italy
| | - Claudia L. Bianchi
- Dipartimento di ChimicaUniversitá degli Studi di Milanovia Golgi 19, 20133 Milano Italy
| | - Gregory S. Patience
- Department of Chemical EngineeringPolytechnique MontréalC.P. 6079, Succ. CV Montréal, QC, H3C 3A7 Canada
| | - Daria C. Boffito
- Department of Chemical EngineeringPolytechnique MontréalC.P. 6079, Succ. CV Montréal, QC, H3C 3A7 Canada
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20
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21
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Tanabe I, Suyama A, Sato T, Fukui KI. Potential Dependence of Electronic Transition Spectra of Interfacial Ionic Liquids Studied by Newly Developed Electrochemical Attenuated Total Reflectance Spectroscopy. Anal Chem 2019; 91:3436-3442. [DOI: 10.1021/acs.analchem.8b04931] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Ichiro Tanabe
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Aki Suyama
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Taiki Sato
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Ken-ichi Fukui
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka 560-8531, Japan
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22
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Surface behavior of low-temperature molten salt mixtures during the transition from liquid to solid. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2018.11.056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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23
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Song Y, Huo F, Jiang Y, Zhang S, Chen S. In Situ Tracking of Organic Reactions at the Vapor/Liquid Interfaces of Ionic Liquids. Chemphyschem 2018; 19:2741-2750. [PMID: 30003635 DOI: 10.1002/cphc.201800476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Indexed: 11/07/2022]
Abstract
The molecular structures of ionic liquids at interfaces play a crucial role in determining their chemical activities in applications. In situ X-ray photoelectron spectroscopy (XPS) was used to track the evolution of X-ray irradiation-induced chemical reactions in a series of ionic liquids ([Cn mim][AuCl4 ]; n=4, 6, 8, 10) on the Si (111) single-crystal surface. Analyses of microstructure and chemical bonding based on the XPS results indicated that reactions occurred at the vapor/liquid interfaces of the ionic liquids. The time-resolved XPS spectra revealed that with increasing irradiation time, the intensity of the peak corresponding to trivalent Au anion decreased for the four ionic liquids as Au was continually reduced to a lower chemical state and finally converted to gold nanoparticles. The rate and conversion of the reaction were associated with the length of the alkyl chain of the ionic liquids cation. Molecular dynamics simulations further revealed that the alkyl chain of the cation in the ionic liquids was oriented towards the vacuum environment at the vapor/liquid interface. Our results provide a real-time atomic-scale experimental evidence of organic reactions at the vapor/liquid interfaces of ionic liquids. The findings are important for understanding the roles of ionic liquids in catalysis, separation, electrochemistry, functional materials, and so on.
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Affiliation(s)
- Yuting Song
- Beijing Key Laboratory of Ionic Liquids Clean Process, Key Laboratory of Green Process and Engineering State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.,Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, 610041, China.,University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Feng Huo
- Beijing Key Laboratory of Ionic Liquids Clean Process, Key Laboratory of Green Process and Engineering State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yi Jiang
- Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Suojiang Zhang
- Beijing Key Laboratory of Ionic Liquids Clean Process, Key Laboratory of Green Process and Engineering State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
| | - Shimou Chen
- Beijing Key Laboratory of Ionic Liquids Clean Process, Key Laboratory of Green Process and Engineering State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
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24
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Buchner F, Uhl B, Forster-Tonigold K, Bansmann J, Groß A, Behm RJ. Structure formation and surface chemistry of ionic liquids on model electrode surfaces-Model studies for the electrode | electrolyte interface in Li-ion batteries. J Chem Phys 2018; 148:193821. [PMID: 30307189 DOI: 10.1063/1.5012878] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Ionic liquids (ILs) are considered as attractive electrolyte solvents in modern battery concepts such as Li-ion batteries. Here we present a comprehensive review of the results of previous model studies on the interaction of the battery relevant IL 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP]+[TFSI]-) with a series of structurally and chemically well-defined model electrode surfaces, which are increasingly complex and relevant for battery applications [Ag(111), Au(111), Cu(111), pristine and lithiated highly oriented pyrolytic graphite (HOPG), and rutile TiO2(110)]. Combining surface science techniques such as high resolution scanning tunneling microscopy and X-ray photoelectron spectroscopy for characterizing surface structure and chemical composition in deposited (sub-)monolayer adlayers with dispersion corrected density functional theory based calculations, this work aims at a molecular scale understanding of the fundamental processes at the electrode | electrolyte interface, which are crucial for the development of the so-called solid electrolyte interphase (SEI) layer in batteries. Performed under idealized conditions, in an ultrahigh vacuum environment, these model studies provide detailed insights on the structure formation in the adlayer, the substrate-adsorbate and adsorbate-adsorbate interactions responsible for this, and the tendency for chemically induced decomposition of the IL. To mimic the situation in an electrolyte, we also investigated the interaction of adsorbed IL (sub-)monolayers with coadsorbed lithium. Even at 80 K, postdeposited Li is found to react with the IL, leading to decomposition products such as LiF, Li3N, Li2S, LixSOy, and Li2O. In the absence of a [BMP]+[TFSI]- adlayer, it tends to adsorb, dissolve, or intercalate into the substrate (metals, HOPG) or to react with the substrate (TiO2) above a critical temperature, forming LiOx and Ti3+ species in the latter case. Finally, the formation of stable decomposition products was found to sensitively change the equilibrium between surface Li and Li+ intercalated in the bulk, leading to a deintercalation from lithiated HOPG in the presence of an adsorbed IL adlayer at >230 K. Overall, these results provide detailed insights into the surface chemistry at the solid | electrolyte interface and the initial stages of SEI formation at electrode surfaces in the absence of an applied potential, which is essential for the further improvement of future Li-ion batteries.
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Affiliation(s)
- Florian Buchner
- Helmholtz Institute Ulm Electrochemical Energy Storage (HIU), Helmholtzstraße 11, D-89081 Ulm, Germany
| | - Benedikt Uhl
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, D-89081 Ulm, Germany
| | - Katrin Forster-Tonigold
- Helmholtz Institute Ulm Electrochemical Energy Storage (HIU), Helmholtzstraße 11, D-89081 Ulm, Germany
| | - Joachim Bansmann
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, D-89081 Ulm, Germany
| | - Axel Groß
- Helmholtz Institute Ulm Electrochemical Energy Storage (HIU), Helmholtzstraße 11, D-89081 Ulm, Germany
| | - R Jürgen Behm
- Helmholtz Institute Ulm Electrochemical Energy Storage (HIU), Helmholtzstraße 11, D-89081 Ulm, Germany
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25
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Fogarty RM, Matthews RP, Ashworth CR, Brandt-Talbot A, Palgrave RG, Bourne RA, Vander Hoogerstraete T, Hunt PA, Lovelock KRJ. Experimental validation of calculated atomic charges in ionic liquids. J Chem Phys 2018; 148:193817. [DOI: 10.1063/1.5011662] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Affiliation(s)
- Richard M. Fogarty
- Department of Chemistry, Imperial College London, London, United Kingdom
| | | | - Claire R. Ashworth
- Department of Chemistry, Imperial College London, London, United Kingdom
| | | | - Robert G. Palgrave
- Department of Chemistry, University College London, London, United Kingdom
| | - Richard A. Bourne
- School of Chemical and Process Engineering and Institute of Process Research and Development, School of Chemistry, University of Leeds, Leeds, United Kingdom
| | | | - Patricia A. Hunt
- Department of Chemistry, Imperial College London, London, United Kingdom
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26
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Wang H, Wu CH, Weatherup RS, Feng B, Ye Y, Liu YS, Glans PA, Guo J, Fang HT, Salmeron MB. X-ray-Induced Fragmentation of Imidazolium-Based Ionic Liquids Studied by Soft X-ray Absorption Spectroscopy. J Phys Chem Lett 2018; 9:785-790. [PMID: 29376377 DOI: 10.1021/acs.jpclett.8b00057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We investigated the X-ray absorption spectroscopy (XAS) fingerprint of EMImTFSI ionic liquid (IL) and its fragmentation products created by X-ray irradiation. To accomplish this, we used an open geometry where an IL droplet is directly exposed in the vacuum chamber and an enclosed geometry where the IL is confined in a cell covered by an X-ray transparent membrane. In the open geometry, the XAS signature was stable and consistent with experimental and theoretical spectra reported in the literature. In contrast, when the IL is enclosed, its XAS evolves continuously under X-ray illumination due to the accumulation of volatile fragmentation products inside the closed cell, while they evaporate in the open geometry. The changes in the XAS from the core levels of relevant elements (C, N, S, F) together with density functional theory calculations allowed us to identify the chemical nature of the fragment products and the chemical bonds most vulnerable to rupture under soft X-ray irradiation.
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Affiliation(s)
- Huixin Wang
- School of Materials Science and Engineering, Harbin Institute of Technology , Harbin 150001, China
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Cheng Hao Wu
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- The Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Robert S Weatherup
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Bingmei Feng
- School of Materials Science and Engineering, Harbin Institute of Technology , Harbin 150001, China
- The Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Yifan Ye
- The Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Yi-Sheng Liu
- The Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | | | - Jinghua Guo
- The Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Hai-Tao Fang
- School of Materials Science and Engineering, Harbin Institute of Technology , Harbin 150001, China
| | - Miquel B Salmeron
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Department of Materials Science and Engineering, University of California at Berkeley , Berkeley, California 94720, United States
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27
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Pavel OD, Podolean I, Parvulescu VI, Taylor SFR, Manyar HG, Ralphs K, Goodrich P, Hardacre C. Impact of SCILL catalysts for the S-S coupling of thiols to disulfides. Faraday Discuss 2018; 206:535-547. [PMID: 28930329 DOI: 10.1039/c7fd00159b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study reports the behaviour of SCILL based catalysts in the oxidative S-S coupling of aliphatic and aromatic thiols, namely 1-butanethiol and thiophenol, to dibutyl disulfide and diphenyl disulfide. A range of ionic liquids (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide) and metal supported catalysts (5% Pt/SiO2; 5% Ru/SiO2; 5% Ru/C; 5% Pt/OMS-2) were used to prepare the SCILL catalysts and all were found to be active for the reaction following the trend 5% Pt-OMS-2 > 5% Pt/SiO2 > 5% Ru/C > 5% Ru/SiO2. The presence of SCILL catalysts afforded high selectivity to the disulfide, and the activity of the SCILL catalyst was dependent on the ionic liquid used. A significant increase in the stability of all the supported metal catalysts was found in the presence of the ionic liquid, and there was no change in the selectivity towards disulfides. This demonstrated that the ionic liquids protect the active sites of the catalyst against sulfation, thus providing more stable and active catalysts.
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Affiliation(s)
- Octavian D Pavel
- University of Bucharest, Faculty of Chemistry, Department of Organic Chemistry, Biochemistry and Catalysis, 030018, Bucharest, Romania.
| | - Iunia Podolean
- University of Bucharest, Faculty of Chemistry, Department of Organic Chemistry, Biochemistry and Catalysis, 030018, Bucharest, Romania.
| | - Vasile I Parvulescu
- University of Bucharest, Faculty of Chemistry, Department of Organic Chemistry, Biochemistry and Catalysis, 030018, Bucharest, Romania.
| | - S F Rebecca Taylor
- The University of Manchester, School of Chemical Engineering & Analytical Science, Manchester, UK
| | - Haresh G Manyar
- Queen's University Belfast, The QUILL Centre/School of Chemistry and Chemical Engineering, Belfast, Northern Ireland, UK.
| | - Kathryn Ralphs
- Queen's University Belfast, The QUILL Centre/School of Chemistry and Chemical Engineering, Belfast, Northern Ireland, UK.
| | - Peter Goodrich
- Queen's University Belfast, The QUILL Centre/School of Chemistry and Chemical Engineering, Belfast, Northern Ireland, UK.
| | - Christopher Hardacre
- Queen's University Belfast, The QUILL Centre/School of Chemistry and Chemical Engineering, Belfast, Northern Ireland, UK. and The University of Manchester, School of Chemical Engineering & Analytical Science, Manchester, UK
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28
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Tanabe I, Suyama A, Sato T, Fukui KI. Systematic analysis of various ionic liquids by attenuated total reflectance spectroscopy (145–450 nm) and quantum chemical calculations. Analyst 2018; 143:2539-2545. [DOI: 10.1039/c8an00563j] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Electronic absorption spectra in 140–450 nm were investigated by attenuated total reflectance spectroscopy and quantum chemical calculations.
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Affiliation(s)
- Ichiro Tanabe
- Department of Materials Engineering Science
- Graduate School of Engineering Science
- Osaka University
- Osaka 560-8531
- Japan
| | - Aki Suyama
- Department of Materials Engineering Science
- Graduate School of Engineering Science
- Osaka University
- Osaka 560-8531
- Japan
| | - Taiki Sato
- Department of Materials Engineering Science
- Graduate School of Engineering Science
- Osaka University
- Osaka 560-8531
- Japan
| | - Ken-ichi Fukui
- Department of Materials Engineering Science
- Graduate School of Engineering Science
- Osaka University
- Osaka 560-8531
- Japan
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29
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Sitaputra W, Stacchiola D, Wishart JF, Wang F, Sadowski JT. In Situ Probing of Ion Ordering at an Electrified Ionic Liquid/Au Interface. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1606357. [PMID: 28498642 DOI: 10.1002/adma.201606357] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/27/2017] [Indexed: 06/07/2023]
Abstract
Charge transport at the interface of electrodes and ionic liquids is critical for the use of the latter as electrolytes. A room-temperature ionic liquid, 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide (EMMIM TFSI), is investigated in situ under applied bias voltage with a novel method using low-energy electron and photoemission electron microscopy. Changes in photoelectron yield as a function of bias applied to electrodes provide a direct measure of the dynamics of ion reconfiguration and electrostatic responses of the EMMIM TFSI. Long-range and correlated ionic reconfigurations that occur near the electrodes are found to be a function of temperature and thickness, which, in turn, relate to ionic mobility and different configurations for out-of-plane ordering near the electrode interfaces, with a critical transition in ion mobility for films thicker than three monolayers.
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Affiliation(s)
- Wattaka Sitaputra
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Dario Stacchiola
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - James F Wishart
- Chemistry Division, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Feng Wang
- Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Jerzy T Sadowski
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
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30
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Maier F, Niedermaier I, Steinrück HP. Perspective: Chemical reactions in ionic liquids monitored through the gas (vacuum)/liquid interface. J Chem Phys 2017; 146:170901. [DOI: 10.1063/1.4982355] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- F. Maier
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen,
Germany
| | - I. Niedermaier
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen,
Germany
| | - H.-P. Steinrück
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen,
Germany
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31
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Surface composition of [BMP][Tf2N] and [PMIm][Tf2N] in the presence of NbF5 and TaF5. A photoelectron spectroscopy study. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2016.08.075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Ohoyama H, Teramoto T. Initial dissolution of D 2O at the gas-liquid interface of the ionic liquid [C 4min][NTf2] associated with hydrogen-bond network formation. Phys Chem Chem Phys 2016; 18:28061-28068. [PMID: 27711407 DOI: 10.1039/c6cp03448a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have studied the initial dissolution of D2O at the interfacial surface of the flowing jet sheet beam of the ionic liquid (IL) [C4min][NTf2] using the King and Wells method as a function of both the temperature and collision energy of the IL. The initial dissolution probability of D2O into the IL [C4min][NTf2] was found to follow the general propensity that the solubility of gases into a liquid decreases with temperature. However, a large partial molar enthalpy and entropy for the initial dissolution of D2O in the IL [C4min][NTf2] were observed from the temperature dependence of the initial dissolution probability: ΔHl = -53 ± 8 kJ mol-1, ΔSl = -210 ± 30 J mol-1 K-1. In addition, it was found that the collision energy significantly reduced the initial dissolution probability. We propose that the associated D2O molecules at the interface of the IL [C4min][NTf2] make a hydrogen-bond network around the [NTf2]- anion before dissolution into the deeper portion of the interface layer.
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Affiliation(s)
- H Ohoyama
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
| | - T Teramoto
- Department of Electrical & Electronic Engineering, College of Science & Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
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33
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Wang R, Qi X, Liu S, He Y, Deng Y. A comparison study on the properties of 1,3-dialkylimidazolium tetrafluoroborate salts prepared by halogen-free and traditional method. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2016.05.092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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34
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Nakajima K, Nakanishi S, Lísal M, Kimura K. Surface structure of imidazolium-based ionic liquids: Quantitative comparison between simulations and high-resolution RBS measurements. J Chem Phys 2016; 144:114702. [PMID: 27004888 DOI: 10.1063/1.4943887] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Elemental depth profiles of 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([CnMIM][TFSI], n = 4, 6, 8) are measured using high-resolution Rutherford backscattering spectroscopy (HRBS). The profiles are compared with the results of molecular dynamics (MD) simulations. Both MD simulations and HRBS measurements show that the depth profiles deviate from the uniform stoichiometric composition in the surface region, showing preferential orientations of ions at the surface. The MD simulations qualitatively reproduce the observed HRBS profiles but the agreement is not satisfactory. The observed discrepancy is ascribed to the capillary waves. By taking account of the surface roughness induced by the capillary waves, the agreement becomes almost perfect.
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Affiliation(s)
- Kaoru Nakajima
- Department of Micro Engineering, Kyoto University, Kyoto-daigaku-katsura, Nishikyo, Kyoto 615-8540, Japan
| | - Shunto Nakanishi
- Department of Micro Engineering, Kyoto University, Kyoto-daigaku-katsura, Nishikyo, Kyoto 615-8540, Japan
| | - Martin Lísal
- Laboratory of Aerosols Chemistry and Physics, Institute of Chemical Process Fundamentals of the CAS, v. v. i., Suchdol, Prague 6 165 02, Czech Republic
| | - Kenji Kimura
- Department of Micro Engineering, Kyoto University, Kyoto-daigaku-katsura, Nishikyo, Kyoto 615-8540, Japan
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35
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Horikawa Y, Tokushima T, Takahashi O, Hoke H, Takamuku T. Correlation between Soft X-ray Absorption and Emission Spectra of the Nitrogen Atoms within Imidazolium-Based Ionic Liquids. J Phys Chem B 2016; 120:7480-7. [DOI: 10.1021/acs.jpcb.6b04132] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Yuka Horikawa
- Department
of Physics and Information Science, Faculty of Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8512, Japan
- Soft
X-ray Spectroscopy Instrumentation Unit, RIKEN SPring-8 Center, Sayo-cho, Sayo, Hyogo 679-5148, Japan
| | - Takashi Tokushima
- Soft
X-ray Spectroscopy Instrumentation Unit, RIKEN SPring-8 Center, Sayo-cho, Sayo, Hyogo 679-5148, Japan
| | - Osamu Takahashi
- Soft
X-ray Spectroscopy Instrumentation Unit, RIKEN SPring-8 Center, Sayo-cho, Sayo, Hyogo 679-5148, Japan
- Institute
for Sustainable Sciences and Development, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - Hiroshi Hoke
- Department
of Chemistry and Applied Chemistry, Graduate School of Science and
Engineering, Saga University, Honjo-machi, Saga 840-8502, Japan
| | - Toshiyuki Takamuku
- Soft
X-ray Spectroscopy Instrumentation Unit, RIKEN SPring-8 Center, Sayo-cho, Sayo, Hyogo 679-5148, Japan
- Department
of Chemistry and Applied Chemistry, Graduate School of Science and
Engineering, Saga University, Honjo-machi, Saga 840-8502, Japan
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36
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Theoretical Studies on the Adsorption of 1-Butyl-3-methyl-imidazolium-hexafluorophosphate (BMI/PF $$_6$$ 6 ) on Au(100) Surfaces. Top Catal 2016. [DOI: 10.1007/s11244-016-0552-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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37
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Niedermaier I, Kolbeck C, Steinrück HP, Maier F. Dual analyzer system for surface analysis dedicated for angle-resolved photoelectron spectroscopy at liquid surfaces and interfaces. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:045105. [PMID: 27131705 DOI: 10.1063/1.4942943] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The investigation of liquid surfaces and interfaces with the powerful toolbox of ultra-high vacuum (UHV)-based surface science techniques generally has to overcome the issue of liquid evaporation within the vacuum system. In the last decade, however, new classes of liquids with negligible vapor pressure at room temperature-in particular, ionic liquids (ILs)-have emerged for surface science studies. It has been demonstrated that particularly angle-resolved X-ray Photoelectron Spectroscopy (ARXPS) allows for investigating phenomena that occur at gas-liquid and liquid-solid interfaces on the molecular level. The results are not only relevant for IL systems but also for liquids in general. In all of these previous ARXPS studies, the sample holder had to be tilted in order to change the polar detection angle of emitted photoelectrons, which restricted the liquid systems to very thin viscous IL films coating a flat solid support. We now report on the concept and realization of a new and unique laboratory "Dual Analyzer System for Surface Analysis (DASSA)" which enables fast ARXPS, UV photoelectron spectroscopy, imaging XPS, and low-energy ion scattering at the horizontal surface plane of macroscopically thick non-volatile liquid samples. It comprises a UHV chamber equipped with two electron analyzers mounted for simultaneous measurements in 0° and 80° emission relative to the surface normal. The performance of DASSA on a first macroscopic liquid system will be demonstrated.
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Affiliation(s)
- Inga Niedermaier
- Lehrstuhl für Physikalische Chemie II, FAU Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Claudia Kolbeck
- Lehrstuhl für Physikalische Chemie II, FAU Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Hans-Peter Steinrück
- Lehrstuhl für Physikalische Chemie II, FAU Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Florian Maier
- Lehrstuhl für Physikalische Chemie II, FAU Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
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38
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Buchner F, Forster-Tonigold K, Bozorgchenani M, Gross A, Behm RJ. Interaction of a Self-Assembled Ionic Liquid Layer with Graphite(0001): A Combined Experimental and Theoretical Study. J Phys Chem Lett 2016; 7:226-233. [PMID: 26713562 DOI: 10.1021/acs.jpclett.5b02449] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The interaction between (sub)monolayers of the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide [BMP](+)[TFSA](-) and graphite(0001), which serves as a model for the anode|electolyte interface in Li-ion batteries, was investigated under ultrahigh vacuum conditions in a combined experimental and theoretical approach. High-resolution scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and dispersion-corrected density functional theory (DFT-D) calculations were employed. After vapor deposition at 300 K, XPS indicates molecular adsorbates with a 1:1 ratio of cations/anions. Cool down to ∼100 K leads to the formation of an ordered (2D) crystalline phase, which coexists with a mobile (2D) liquid. DFT-D calculations reveal that adsorbed [BMP](+) and [TFSA](-) species are arranged alternately in a row-like adsorption structure (cation-anion-cation-anion) and that adsorption is dominated by dispersion interactions between adlayer and substrate, on the one hand, and electrostatic interactions between the ions in a row, on the other hand. Simulated STM images of that structure closely resemble the experimental molecular resolved STM images and show that the resolved features mostly stem from the cations.
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Affiliation(s)
- Florian Buchner
- Helmholtz-Institute-Ulm (HIU) , Electrochemical Energy Storage, Helmholtzstraße 11, D-89081 Ulm, Germany
| | - Katrin Forster-Tonigold
- Helmholtz-Institute-Ulm (HIU) , Electrochemical Energy Storage, Helmholtzstraße 11, D-89081 Ulm, Germany
| | - Maral Bozorgchenani
- Ulm University , Institute of Surface Chemistry and Catalysis, Albert-Einstein-Allee 47, D-89081 Ulm, Germany
| | - Axel Gross
- Helmholtz-Institute-Ulm (HIU) , Electrochemical Energy Storage, Helmholtzstraße 11, D-89081 Ulm, Germany
- Ulm University , Institute of Theoretical Chemistry, Albert-Einstein-Allee 11, D-89081 Ulm, Germany
| | - R Jürgen Behm
- Helmholtz-Institute-Ulm (HIU) , Electrochemical Energy Storage, Helmholtzstraße 11, D-89081 Ulm, Germany
- Ulm University , Institute of Surface Chemistry and Catalysis, Albert-Einstein-Allee 47, D-89081 Ulm, Germany
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39
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Tanabe I, Kurawaki Y, Morisawa Y, Ozaki Y. Electronic absorption spectra of imidazolium-based ionic liquids studied by far-ultraviolet spectroscopy and quantum chemical calculations. Phys Chem Chem Phys 2016; 18:22526-30. [DOI: 10.1039/c6cp02930b] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electronic absorption spectra of imidazolium-based ionic liquids were studied by far- and deep-ultraviolet spectroscopy and quantum chemical calculations.
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Affiliation(s)
- Ichiro Tanabe
- Department of Chemistry
- School of Science and Technology
- Kwansei Gakuin University
- Sanda
- Japan
| | - Yuji Kurawaki
- Department of Chemistry
- School of Science and Technology
- Kwansei Gakuin University
- Sanda
- Japan
| | - Yusuke Morisawa
- Department of Chemistry
- School of Science and Technology
- Kindai University
- Higashi-Osaka
- Japan
| | - Yukihiro Ozaki
- Department of Chemistry
- School of Science and Technology
- Kwansei Gakuin University
- Sanda
- Japan
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40
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Blundell RK, Delorme AE, Smith EF, Licence P. An ARXPS and ERXPS study of quaternary ammonium and phosphonium ionic liquids: utilising a high energy Ag Lα′ X-ray source. Phys Chem Chem Phys 2016; 18:6122-31. [DOI: 10.1039/c5cp07089a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A series of ammonium- and phosphonium-based ionic liquids have been probed using X-ray photoelectron spectroscopy (XPS) with a high energy Ag Lα′ X-ray source.
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Affiliation(s)
- Rebecca K. Blundell
- The GlaxoSmithKline Carbon Neutral Laboratory
- School of Chemistry
- The University of Nottingham
- Nottingham NG7 2RD
- UK
| | - Astrid E. Delorme
- The GlaxoSmithKline Carbon Neutral Laboratory
- School of Chemistry
- The University of Nottingham
- Nottingham NG7 2RD
- UK
| | - Emily F. Smith
- The GlaxoSmithKline Carbon Neutral Laboratory
- School of Chemistry
- The University of Nottingham
- Nottingham NG7 2RD
- UK
| | - Peter Licence
- The GlaxoSmithKline Carbon Neutral Laboratory
- School of Chemistry
- The University of Nottingham
- Nottingham NG7 2RD
- UK
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41
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Borgwardt M, Wilke M, Kiyan IY, Aziz EF. Ultrafast excited states dynamics of [Ru(bpy)3]2+ dissolved in ionic liquids. Phys Chem Chem Phys 2016; 18:28893-28900. [DOI: 10.1039/c6cp05655e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In this work, we demonstrate the potential of room-temperature ionic liquids as solvents to investigate the excited states dynamics of [Ru(bpy)3]2+ by means of time-resolved photoelectron spectroscopy.
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Affiliation(s)
- Mario Borgwardt
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
| | - Martin Wilke
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
| | - Igor Yu. Kiyan
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
| | - Emad F. Aziz
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
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42
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Men S, Mitchell DS, Lovelock KRJ, Licence P. X-ray Photoelectron Spectroscopy of Pyridinium-Based Ionic Liquids: Comparison to Imidazolium- and Pyrrolidinium-Based Analogues. Chemphyschem 2015; 16:2211-8. [PMID: 25952131 PMCID: PMC4768647 DOI: 10.1002/cphc.201500227] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Indexed: 11/08/2022]
Abstract
We investigate eight 1-alkylpyridinium-based ionic liquids of the form [Cn Py][A] by using X-ray photoelectron spectroscopy (XPS). The electronic environment of each element of the ionic liquids is analyzed. In particular, a reliable fitting model is developed for the C 1s region that applies to each of the ionic liquids. This model allows the accurate charge correction of binding energies and the determination of reliable and reproducible binding energies for each ionic liquid. Shake-up/off phenomena are determinedfor both C 1s and N 1s spectra. The electronic interaction between cations and anions is investigated for both simple ionic liquids and an example of an ionic-liquid mixture; the effect of the anion on the electronic environment of the cation is also explored. Throughout the study, a detailed comparison is made between [C8 Py][A] and analogues including 1-octyl-1-methylpyrrolidinium- ([C8 C1 Pyrr][A]), and 1-octyl-3-methylimidazolium- ([C8 C1 Im][A]) based samples, where X is common to all ionic liquids.
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Affiliation(s)
- Shuang Men
- School of Material Science and Engineering, Shenyang Ligong University, Shenyang 110168 (P. R. China).
- School of Chemistry, The University of Nottingham, Nottingham NG7 2RD (UK).
| | - Daniel S Mitchell
- School of Chemistry, The University of Nottingham, Nottingham NG7 2RD (UK)
| | | | - Peter Licence
- School of Chemistry, The University of Nottingham, Nottingham NG7 2RD (UK).
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43
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Akçay A, Babucci M, Balci V, Uzun A. A model to predict maximum tolerable temperatures of metal-oxide-supported 1- n -butyl-3-methylimidazolium based ionic liquids. Chem Eng Sci 2015. [DOI: 10.1016/j.ces.2014.11.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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44
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Regeta K, Bannwarth C, Grimme S, Allan M. Free electrons and ionic liquids: study of excited states by means of electron-energy loss spectroscopy and the density functional theory multireference configuration interaction method. Phys Chem Chem Phys 2015; 17:15771-80. [DOI: 10.1039/c5cp01417d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Collisions of slow electrons with ionic liquids and DFT/MRCI calculations reveal triplet states and interesting physics at low energies.
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Affiliation(s)
- Khrystyna Regeta
- Department of Chemistry
- University of Fribourg
- Fribourg
- Switzerland
| | - Christoph Bannwarth
- Mulliken Center for Theoretical Chemistry
- Institut für Physikalische und Theoretische Chemie
- Universität Bonn
- 53115 Bonn
- Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry
- Institut für Physikalische und Theoretische Chemie
- Universität Bonn
- 53115 Bonn
- Germany
| | - Michael Allan
- Department of Chemistry
- University of Fribourg
- Fribourg
- Switzerland
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45
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Nakajima K, Miyashita M, Suzuki M, Kimura K. Surface structures of binary mixtures of imidazolium-based ionic liquids using high-resolution Rutherford backscattering spectroscopy and time of flight secondary ion mass spectroscopy. J Chem Phys 2014; 139:224701. [PMID: 24329076 DOI: 10.1063/1.4838376] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Surface structures of binary mixtures of imidazolium-based ionic liquids having a common anion (bis(trifluoromethanesulfonyl)imide ([TFSI]), namely [C2MIM]1-x[C10MIM]x[TFSI] (x = 0.5 and 0.1), are studied using high-resolution Rutherford backscattering spectroscopy (HRBS) and time of flight secondary ion mass spectroscopy (TOF-SIMS). Although both measurements show surface segregation of [C10MIM] the degrees of the segregation are different. The surface fraction xsurf of [C10MIM] is estimated to be 0.6 ± 0.05 and 0.18 ± 0.02 by HRBS for x = 0.5 and 0.1, respectively. On the other hand, TOF-SIMS indicates much stronger surface segregation, namely xsurf = 0.83 ± 0.03 and 0.42 ± 0.04 for x = 0.5 and 0.1, respectively. The observed discrepancy can be attributed to the difference in the probing depth between HRBS and TOF-SIMS. The observed surface segregation can be roughly explained in terms of surface tension.
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Affiliation(s)
- Kaoru Nakajima
- Department of Micro Engineering, Kyoto University, Kyoto-daigaku-Katsura, Nishikyo, Kyoto 615-8549, Japan
| | - Motoki Miyashita
- Department of Micro Engineering, Kyoto University, Kyoto-daigaku-Katsura, Nishikyo, Kyoto 615-8549, Japan
| | - Motofumi Suzuki
- Department of Micro Engineering, Kyoto University, Kyoto-daigaku-Katsura, Nishikyo, Kyoto 615-8549, Japan
| | - Kenji Kimura
- Department of Micro Engineering, Kyoto University, Kyoto-daigaku-Katsura, Nishikyo, Kyoto 615-8549, Japan
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Viau L, Hihn J, Lakard S, Moutarlier V, Flaud V, Lakard B. Full characterization of polypyrrole thin films electrosynthesized in room temperature ionic liquids, water or acetonitrile. Electrochim Acta 2014. [DOI: 10.1016/j.electacta.2014.05.143] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Andersson G, Ridings C. Ion Scattering Studies of Molecular Structure at Liquid Surfaces with Applications in Industrial and Biological Systems. Chem Rev 2014; 114:8361-87. [DOI: 10.1021/cr400417f] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Gunther Andersson
- Centre
for NanoScale Science
and Technology, Flinders University, Adelaide, South Australia 5001, Australia
| | - Christiaan Ridings
- Centre
for NanoScale Science
and Technology, Flinders University, Adelaide, South Australia 5001, Australia
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Ridings C, Warr GG, Andersson GG. Composition of the outermost layer and concentration depth profiles of ammonium nitrate ionic liquid surfaces. Phys Chem Chem Phys 2014; 14:16088-95. [PMID: 23103987 DOI: 10.1039/c2cp43035e] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Differences in the surface structure of protic ionic liquids (ILs) with three different cations and a common anion; ethyl-, propyl- and 2-hydroxyethyl- (or ethanol-) ammonium nitrate (EAN, PAN and EtAN, respectively) have been observed by neutral impact collision ion scattering spectroscopy (NICISS) and metastable induced electron spectroscopy/ultraviolet photoelectron spectroscopy (MIES/UPS). NICISS is used to determine the concentration depth profiles of the elements in each IL and it reveals an enrichment of cation alkyl chains of PAN and EtAN in the outermost layer compared to EAN, and a corresponding depletion of nitrate from the outermost layer of the EtAN surface. MIES probes the molecular orbitals of only the species in the outermost layer of a sample and confirms that, while both the anion and the cation are present to some degree at the surface of all three ILs, the cation is enriched to a greater extent at the surface of PAN and EtAN compared to EAN.
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Affiliation(s)
- Christiaan Ridings
- Centre for NanoScale Science and Technology, Flinders University, SA, Australia
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Ulbrich A, Reinmöller M, Beenken WJ, Krischok S. Photoelectron spectroscopy on ionic liquid surfaces — Theory and experiment. J Mol Liq 2014. [DOI: 10.1016/j.molliq.2014.01.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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50
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Kolbeck C, Niedermaier I, Deyko A, Lovelock KRJ, Taccardi N, Wei W, Wasserscheid P, Maier F, Steinrück HP. Influence of Substituents and Functional Groups on the Surface Composition of Ionic Liquids. Chemistry 2014; 20:3954-65. [DOI: 10.1002/chem.201304549] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Indexed: 11/10/2022]
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