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Malerz S, Haak H, Trinter F, Stephansen AB, Kolbeck C, Pohl M, Hergenhahn U, Meijer G, Winter B. A setup for studies of photoelectron circular dichroism from chiral molecules in aqueous solution. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:015101. [PMID: 35104975 DOI: 10.1063/5.0072346] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
We present a unique experimental design that enables the measurement of photoelectron circular dichroism (PECD) from chiral molecules in aqueous solution. The effect is revealed from the intensity difference of photoelectron emission into a backward-scattering angle relative to the photon propagation direction when ionizing with circularly polarized light of different helicity. This leads to asymmetries (normalized intensity differences) that depend on the handedness of the chiral sample and exceed the ones in conventional dichroic mechanisms by orders of magnitude. The asymmetry is largest for photon energies within several electron volts above the ionization threshold. A primary aim is to explore the effect of hydration on PECD. The modular and flexible design of our experimental setup EASI (Electronic structure from Aqueous Solutions and Interfaces) also allows for detection of more common photoelectron angular distributions, requiring distinctively different detection geometries and typically using linearly polarized light. A microjet is used for liquid-sample delivery. We describe EASI's technical features and present two selected experimental results, one based on synchrotron-light measurements and the other performed in the laboratory, using monochromatized He-II α radiation. The former demonstrates the principal effectiveness of PECD detection, illustrated for prototypic gas-phase fenchone. We also discuss the first data from liquid fenchone. In the second example, we present valence photoelectron spectra from liquid water and NaI aqueous solution, here obtained from a planar-surface microjet (flatjet). This new development features a more favorable symmetry for angle-dependent photoelectron measurements.
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Affiliation(s)
- Sebastian Malerz
- Molecular Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Henrik Haak
- Molecular Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Florian Trinter
- Molecular Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Anne B Stephansen
- Molecular Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Claudia Kolbeck
- Molecular Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Marvin Pohl
- Molecular Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Uwe Hergenhahn
- Molecular Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Gerard Meijer
- Molecular Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Bernd Winter
- Molecular Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
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Jia M, Broderick A, Newberg JT. The Influence of Water Vapor on the Electrochemical Shift of an Ionic Liquid Measured by Ambient Pressure X-ray Photoelectron Spectroscopy. Chemphyschem 2021; 22:633-640. [PMID: 33534914 DOI: 10.1002/cphc.202001041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/02/2021] [Indexed: 11/09/2022]
Abstract
Ionic liquids (ILs) are considered to be one of the steppingstones to fabricate next generation electrochemical devices given their unique physical and chemical properties. The addition of water to ILs significantly impact electrochemical related properties including viscosity, density, conductivity, and electrochemical window. Herein we utilize ambient pressure X-ray photoelectron spectroscopy (APXPS) to examine the impact of water on values of the electrochemical shift (S), which is determined by measuring changes in binding energy shifts as a function of an external bias. APXPS spectra of C 1s, O 1s and N 1s regions are examined for the IL 1-butyl-3-methylimidazolium acetate, [C4 mim][OAc], at the IL/gas interface as a function of both water vapor pressure and external bias. Results reveal that in the absence of water vapor there is an IL ohmic drop between the working electrode and quasi reference electrode, giving rise to chemical specific S values of less than one. Upon introducing water vapor, S values approach one as a function of increasing water vapor pressure, indicating a decrease in the IL ohmic drop as the IL/water mixture becomes more conductive and the potential drop is driven by the electric double layer at the electrode/IL interface.
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Affiliation(s)
- Meng Jia
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Alicia Broderick
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA.,Present Address: U.S. Department of Homeland Security, Science and Technology Directorate's Transportation Security Laboratory, Atlantic City, NJ, 08405, USA
| | - John T Newberg
- Material Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
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King PDC, Picozzi S, Egdell RG, Panaccione G. Angle, Spin, and Depth Resolved Photoelectron Spectroscopy on Quantum Materials. Chem Rev 2021; 121:2816-2856. [PMID: 33346644 DOI: 10.1021/acs.chemrev.0c00616] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of X-ray based electron spectroscopies in determining chemical, electronic, and magnetic properties of solids has been well-known for several decades. A powerful approach is angle-resolved photoelectron spectroscopy, whereby the kinetic energy and angle of photoelectrons emitted from a sample surface are measured. This provides a direct measurement of the electronic band structure of crystalline solids. Moreover, it yields powerful insights into the electronic interactions at play within a material and into the control of spin, charge, and orbital degrees of freedom, central pillars of future solid state science. With strong recent focus on research of lower-dimensional materials and modified electronic behavior at surfaces and interfaces, angle-resolved photoelectron spectroscopy has become a core technique in the study of quantum materials. In this review, we provide an introduction to the technique. Through examples from several topical materials systems, including topological insulators, transition metal dichalcogenides, and transition metal oxides, we highlight the types of information which can be obtained. We show how the combination of angle, spin, time, and depth-resolved experiments are able to reveal "hidden" spectral features, connected to semiconducting, metallic and magnetic properties of solids, as well as underlining the importance of dimensional effects in quantum materials.
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Affiliation(s)
- Phil D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Silvia Picozzi
- Consiglio Nazionale delle Ricerche, CNR-SPIN, Via dei Vestini 31, Chieti 66100, Italy
| | - Russell G Egdell
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Giancarlo Panaccione
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
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Probing a battery electrolyte drop with ambient pressure photoelectron spectroscopy. Nat Commun 2019; 10:3080. [PMID: 31300638 PMCID: PMC6626006 DOI: 10.1038/s41467-019-10803-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Accepted: 06/04/2019] [Indexed: 11/08/2022] Open
Abstract
Operando ambient pressure photoelectron spectroscopy in realistic battery environments is a key development towards probing the functionality of the electrode/electrolyte interface in lithium-ion batteries that is not possible with conventional photoelectron spectroscopy. Here, we present the ambient pressure photoelectron spectroscopy characterization of a model electrolyte based on 1M bis(trifluoromethane)sulfonimide lithium salt in propylene carbonate. For the first time, we show ambient pressure photoelectron spectroscopy data of propylene carbonate in the liquid phase by using solvent vapor as the stabilizing environment. This enables us to separate effects from salt and solvent, and to characterize changes in electrolyte composition as a function of probing depth. While the bulk electrolyte meets the expected composition, clear accumulation of ionic species is found at the electrolyte surface. Our results show that it is possible to measure directly complex liquids such as battery electrolytes, which is an important accomplishment towards true operando studies. Here the authors probe a model electrolyte of a Li-ion battery for insights into the composition and concentration variation using ambient pressure photoelectron spectroscopy. The work highlights the necessity to stabilize the liquid phases and to differentiate surface and bulk compositions in the measurements.
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Broderick A, Rocha MA, Khalifa Y, Shiflett MB, Newberg JT. Mass Transfer Thermodynamics through a Gas-Liquid Interface. J Phys Chem B 2019; 123:2576-2584. [PMID: 30803233 DOI: 10.1021/acs.jpcb.9b00958] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular level information about thermodynamic variations (enthalpy, entropy, and free energy) of a gas molecule as it crosses a gas-liquid interface is strongly lacking from an experimental perspective under equilibrium conditions. Herein, we perform in situ measurements of water interacting with the ionic liquid (IL) 1-butyl-3-methylimidazolium acetate, [C4mim][Ace], using ambient pressure X-ray photoelectron spectroscopy in order to assess the interfacial uptake of water quantitatively as a function of temperature, pressure, and water mole fraction ( xw). The surface spectroscopy results are compared to existing bulk water absorption experiments, showing that the amount of water in the interfacial region is consistently greater than that in the bulk. The enthalpy and entropy of water sorption vary significantly between the gas-liquid interface and the bulk as a function of xw, with a crossover that occurs near xw = 0.6 where the water-IL mixture converts from being homogeneous ( xw < 0.6) to nanostructured ( xw > 0.6). Free energy results reveal that water at the gas-IL interface is thermodynamically more favorable than that in the bulk, consistent with the enhanced water concentration in the interfacial region. The results herein show that the efficacy for an ionic liquid to absorb a gas phase molecule is not merely a function of bulk solvation parameters but also is significantly influenced by the thermodynamics occurring across the gas-IL interface during the mass transfer process.
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Affiliation(s)
- Alicia Broderick
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - M Alejandra Rocha
- Department of Chemical and Petroleum Engineering , University of Kansas , Lawrence , Kansas 66045 , United States
| | - Yehia Khalifa
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Mark B Shiflett
- Department of Chemical and Petroleum Engineering , University of Kansas , Lawrence , Kansas 66045 , United States
| | - John T Newberg
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
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Khalifa Y, Broderick A, Newberg JT. Surface enhancement of water at the ionic liquid-gas interface of [HMIM][Cl] under ambient water vapor. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:325001. [PMID: 29972140 DOI: 10.1088/1361-648x/aad102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The ionic liquid-gas interface of 1-hexyl-3-methyl-imidazolium chloride, [HMIM][Cl], was examined in the presence of water vapor using lab-based ambient pressure x-ray photoelectron spectroscopy (APXPS) at room temperature. The interfacial water uptake was measured quantitatively in the pressure range of high vacuum up to a maximum of 5 Torr (27% RH) and back to high vacuum in a systematic manner. Water mole fractions in the interface determined from APXPS were compared to previously published tandem differential mobility analysis results on [HMIM][Cl] nanodroplets. Our findings show that water constitutes a significantly larger mole fraction at the interface when compared to the bulk. Additionally, the reverse isotherms showed that the uptake of water at the interface of [HMIM][Cl] is a reversible process.
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Affiliation(s)
- Yehia Khalifa
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States of America
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Roy K, Artiglia L, van Bokhoven JA. Ambient Pressure Photoelectron Spectroscopy: Opportunities in Catalysis from Solids to Liquids and Introducing Time Resolution. ChemCatChem 2018. [DOI: 10.1002/cctc.201701522] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Kanak Roy
- Institute for Chemical and Bioengineering; ETH Zürich; Zürich Switzerland
- Laboratory for Catalysis and Sustainable Chemistry; Paul Scherrer Institute; Villigen Switzerland
| | - Luca Artiglia
- Laboratory for Catalysis and Sustainable Chemistry; Paul Scherrer Institute; Villigen Switzerland
| | - Jeroen A. van Bokhoven
- Institute for Chemical and Bioengineering; ETH Zürich; Zürich Switzerland
- Laboratory for Catalysis and Sustainable Chemistry; Paul Scherrer Institute; Villigen Switzerland
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Seidel R, Pohl MN, Ali H, Winter B, Aziz EF. Advances in liquid phase soft-x-ray photoemission spectroscopy: A new experimental setup at BESSY II. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:073107. [PMID: 28764540 DOI: 10.1063/1.4990797] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A state-of-the-art experimental setup for soft X-ray photo- and Auger-electron spectroscopy from liquid phase has been built for operation at the synchrotron-light facility BESSY II, Berlin. The experimental station is named SOL3, which is derived from solid, solution, and solar, and refers to the aim of studying solid-liquid interfaces, optionally irradiated by photons in the solar spectrum. SOL3 is equipped with a high-transmission hemispherical electron analyzer for detecting electrons emitted from small molecular aggregates, nanoparticles, or biochemical molecules and their components in (aqueous) solutions, either in vacuum or in an ambient pressure environment. In addition to conventional energy-resolved electron detection, SOL3 enables detection of electron angular distributions by the combination of a ±11° acceptance angle of the electron analyzer and a rotation of the analyzer in the polarization plane of the incoming synchrotron-light beam. The present manuscript describes the technical features of SOL3, and we also report the very first measurements of soft-X-ray photoemission spectra from a liquid microjet of neat liquid water and of TiO2-nanoparticle aqueous solution obtained with this new setup, highlighting the necessity for state-of-the-art electron detection.
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Affiliation(s)
- Robert Seidel
- Helmholtz-Zentrum Berlin für Materialien und Energie, Methods for Material Development, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
| | - Marvin N Pohl
- Helmholtz-Zentrum Berlin für Materialien und Energie, Methods for Material Development, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
| | - Hebatallah Ali
- Helmholtz-Zentrum Berlin für Materialien und Energie, Methods for Material Development, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
| | - Bernd Winter
- Helmholtz-Zentrum Berlin für Materialien und Energie, Methods for Material Development, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
| | - Emad F Aziz
- Helmholtz-Zentrum Berlin für Materialien und Energie, Methods for Material Development, Albert-Einstein-Straße 15, D-12489 Berlin, Germany
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Kerherve G, Regoutz A, Bentley D, Hood C, Feeley K, Knight S, Robson A, Turner C, Singh N, Pontefract J, Åhlund J, Kahk JM, Villar-Garcia IJ, Payne DJ. Laboratory-based high pressure X-ray photoelectron spectroscopy: A novel and flexible reaction cell approach. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:033102. [PMID: 28372401 DOI: 10.1063/1.4975096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The last 10-15 years have witnessed a resurgence in the application of high pressure X-ray photoelectron spectroscopy, mainly through the development of new electron energy analyser designs and the utilization of high-brilliance synchrotron radiation sources. To continue this expansion of the technique, it is crucial that instruments are developed for the home-laboratory, considering that this is where the vast majority of traditional ultra-high vacuum (UHV) X-ray photoelectron spectroscopy is performed. The research presented here introduces a new addition to the field, an instrument capable of performing spectroscopy measurements from UHV to high pressure (25 mbar), achieved using a retractable and modular reaction cell design. The ease of use, stability (of analyser, X-ray source, and gas delivery, etc.), and overall capability of the instrument will be demonstrated.
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Affiliation(s)
- Gwilherm Kerherve
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Anna Regoutz
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - David Bentley
- Vacgen Ltd., Maunsell Road, Castleham Industrial Estate, Hastings, East Sussex TN38 9NN, United Kingdom
| | - Colin Hood
- Vacgen Ltd., Maunsell Road, Castleham Industrial Estate, Hastings, East Sussex TN38 9NN, United Kingdom
| | - Keith Feeley
- Vacgen Ltd., Maunsell Road, Castleham Industrial Estate, Hastings, East Sussex TN38 9NN, United Kingdom
| | - Stewart Knight
- Vacgen Ltd., Maunsell Road, Castleham Industrial Estate, Hastings, East Sussex TN38 9NN, United Kingdom
| | - Anthony Robson
- Vacgen Ltd., Maunsell Road, Castleham Industrial Estate, Hastings, East Sussex TN38 9NN, United Kingdom
| | - Craig Turner
- Vacgen Ltd., Maunsell Road, Castleham Industrial Estate, Hastings, East Sussex TN38 9NN, United Kingdom
| | - Nick Singh
- Vacgen Ltd., Maunsell Road, Castleham Industrial Estate, Hastings, East Sussex TN38 9NN, United Kingdom
| | - John Pontefract
- Vacgen Ltd., Maunsell Road, Castleham Industrial Estate, Hastings, East Sussex TN38 9NN, United Kingdom
| | - John Åhlund
- Scienta Omicron AB, P.O. Box 15120, 750 15 Uppsala, Sweden
| | - Juhan M Kahk
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Ignacio J Villar-Garcia
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - David J Payne
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
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