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Piontek S, Naujoks D, Tabassum T, DelloStritto MJ, Jaugstetter M, Hosseini P, Corva M, Ludwig A, Tschulik K, Klein ML, Petersen PB. Probing the Gold/Water Interface with Surface-Specific Spectroscopy. ACS PHYSICAL CHEMISTRY AU 2023; 3:119-129. [PMID: 36718265 PMCID: PMC9881240 DOI: 10.1021/acsphyschemau.2c00044] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 12/08/2022] [Accepted: 12/08/2022] [Indexed: 01/05/2023]
Abstract
Water is an integral component in electrochemistry, in the generation of the electric double layer, and in the propagation of the interfacial electric fields into the solution; however, probing the molecular-level structure of interfacial water near functioning electrode surfaces remains challenging. Due to the surface-specificity, sum-frequency-generation (SFG) spectroscopy offers an opportunity to investigate the structure of water near working electrochemical interfaces but probing the hydrogen-bonded structure of water at this buried electrode-electrolyte interface was thought to be impossible. Propagating the laser beams through the solvent leads to a large attenuation of the infrared light due to the absorption of water, and interrogating the interface by sending the laser beams through the electrode normally obscures the SFG spectra due to the large nonlinear response of conduction band electrons. Here, we show that the latter limitation is removed when the gold layer is thin. To demonstrate this, we prepared Au gradient films on CaF2 with a thickness between 0 and 8 nm. SFG spectra of the Au gradient films in contact with H2O and D2O demonstrate that resonant water SFG spectra can be obtained using Au films with a thickness of ∼2 nm or less. The measured spectra are distinctively different from the frequency-dependent Fresnel factors of the interface, suggesting that the features we observe in the OH stretching region indeed do not arise from the nonresonant response of the Au films. With the newfound ability to probe interfacial solvent structure at electrode/aqueous interfaces, we hope to provide insights into more efficient electrolyte composition and electrode design.
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Affiliation(s)
- Stefan
M. Piontek
- Faculty
of Chemistry and Biochemistry, Ruhr-Universität
Bochum, 44801 Bochum, Germany,Light
Conversion Inc., Vilnius City Municipality, Vilnius 10234, Lithuania
| | - Dennis Naujoks
- Faculty
of Mechanical Engineering, Institute for Materials and ZGH, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Tadneem Tabassum
- Faculty
of Chemistry and Biochemistry, Ruhr-Universität
Bochum, 44801 Bochum, Germany
| | - Mark J. DelloStritto
- Institute
for Computational Molecular Science, Temple
University, Philadelphia, 19122 Pennsylvania, United States
| | | | - Pouya Hosseini
- Max-Planck-Institut
für Eisenforschung GmbH, 40237 Düsseldorf, Germany
| | - Manuel Corva
- Faculty
of Chemistry and Biochemistry, Ruhr-Universität
Bochum, 44801 Bochum, Germany
| | - Alfred Ludwig
- Faculty
of Mechanical Engineering, Institute for Materials and ZGH, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Kristina Tschulik
- Faculty
of Chemistry and Biochemistry, Ruhr-Universität
Bochum, 44801 Bochum, Germany
| | - Michael L. Klein
- Institute
for Computational Molecular Science, Temple
University, Philadelphia, 19122 Pennsylvania, United States
| | - Poul B. Petersen
- Faculty
of Chemistry and Biochemistry, Ruhr-Universität
Bochum, 44801 Bochum, Germany,
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Li X, Lin X, Li Y, Liu WT. Gate Alignment of Liquid Water Molecules in Electric Double Layer. Front Chem 2021; 9:717167. [PMID: 34485244 PMCID: PMC8416066 DOI: 10.3389/fchem.2021.717167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 08/02/2021] [Indexed: 11/13/2022] Open
Abstract
The behavior of liquid water molecules near an electrified interface is important to many disciplines of science and engineering. In this study, we applied an external gate potential to the silica/water interface via an electrolyte-insulator-semiconductor (EIS) junction to control the surface charging state. Without varying the ionic composition in water, the electrical gating allowed an efficient tuning of the interfacial charge density and field. Using the sum-frequency vibrational spectroscopy, we found a drastic enhancement of interfacial OH vibrational signals at high potential in weakly acidic water, which exceeded that from conventional bulk-silica/water interfaces even in strong basic solutions. Analysis of the spectra indicated that it was due to the alignment of liquid water molecules through the electric double layer, where the screening was weak because of the low ion density. Such a combination of strong field and weak screening demonstrates the unique tuning capability of the EIS scheme, and would allow us to investigate a wealth of phenomena at charged oxide/water interfaces.
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Affiliation(s)
- Xiaoqun Li
- Physics Department, State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures [Ministry of Education (MOE)], Fudan University, Shanghai, China
| | - Xin Lin
- Physics Department, State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures [Ministry of Education (MOE)], Fudan University, Shanghai, China
| | - Ying Li
- Physics Department, State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures [Ministry of Education (MOE)], Fudan University, Shanghai, China
| | - Wei-Tao Liu
- Physics Department, State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures [Ministry of Education (MOE)], Fudan University, Shanghai, China
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Li X, Pramhaas V, Rameshan C, Blaha P, Rupprechter G. Coverage-Induced Orientation Change: CO on Ir(111) Monitored by Polarization-Dependent Sum Frequency Generation Spectroscopy and Density Functional Theory. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2020; 124:18102-18111. [PMID: 32855760 PMCID: PMC7444014 DOI: 10.1021/acs.jpcc.0c04986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/21/2020] [Indexed: 05/16/2023]
Abstract
Polarization-dependent sum frequency generation (SFG) spectroscopy was applied to study the adsorption of carbon monoxide (CO) on the well-ordered (annealed) Ir(111) single-crystal surface at various CO coverages. Coverage was adjusted by varying the substrate temperature (300-575 K) and/or gas pressure (10-7 to 1.0 mbar). Under all conditions investigated, only a single absorption band at 2038-2094 cm-1 was observed, characteristic of linearly bonded (on-top) CO. Using different polarizations, PPP and SSP spectra were acquired with a high signal-to-noise ratio, whereby tilt angles of CO on Ir(111) could be determined for the first time by SFG. It was found that not only the vibrational frequency of on-top CO but also the tilt angle was strongly coverage-dependent. The higher the coverage was, the larger the vibrational frequency and the tilt angle were. At about 0.7 ML coverage, a CO tilt angle of at least 20° was observed, which is in good agreement with density functional theory (DFT) calculations. In addition, the molecular hyperpolarizability ratio (R) of CO (at 0.13 ML in UHV) was determined to be 0.08. Based on the combined SFG/DFT results, it may change to 0.29 at 0.77 ML coverage.
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Li X, Rupprechter G. A modeling analysis of molecular orientation at interfaces by polarization-dependent sum frequency generation vibrational spectroscopy. CHINESE JOURNAL OF CATALYSIS 2019. [DOI: 10.1016/s1872-2067(19)63357-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Li X, Roiaz M, Pramhaas V, Rameshan C, Rupprechter G. Polarization-Dependent SFG Spectroscopy of Near Ambient Pressure CO Adsorption on Pt(111) and Pd(111) Revisited. Top Catal 2018; 61:751-762. [PMID: 29950796 PMCID: PMC6010505 DOI: 10.1007/s11244-018-0949-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polarization-dependent sum frequency generation (SFG) vibrational spectroscopy was employed to examine CO overlayers on Pt(111) and Pd(111) single crystal surfaces at room temperature. Utilizing different polarization combinations (SSP and PPP) of the visible and SFG light allows to determine the molecular orientation (tilt angle) of interface molecules but the analysis of the measured \documentclass[12pt]{minimal}
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\begin{document}$$I_{\text{ppp}}/I_{\text{ssp}}$$\end{document}Ippp/Issp is involved and requires a proper optical interface model. For CO/Pt(111), the hyperpolarizability ratio \documentclass[12pt]{minimal}
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\begin{document}$$\left( {R={\beta _{aac}}/{\beta _{ccc}}={\beta _{bbc}}/{\beta _{ccc}}} \right)$$\end{document}R=βaac/βccc=βbbc/βccc is not exactly known and varying R in the range 0.1–0.5 yields tilt angles of 40°–0°, respectively. Based on the known perpendicular adsorption of CO on Pt, an exact R-value of 0.49 was determined. Polarization-dependent SFG spectra in the pressure range 10−4 to 36 mbar did not indicate any change of the tilt angle of adsorbed CO. Modeling also indicated a strong dependence of \documentclass[12pt]{minimal}
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\begin{document}$${I_{{\text{ppp}}}}/{I_{{\text{ssp}}}}$$\end{document}Ippp/Issp on the incidence angles of visible and IR laser beams. Complementing previous low temperature/low pressure data, room temperature CO adsorption on Pd(111) was examined from 10−6 to 250 mbar. The absolute PPP and SSP spectral intensities on Pt and Pd were simulated, as well as the expected \documentclass[12pt]{minimal}
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\begin{document}$${I_{{\text{ppp}}}}/{I_{{\text{ssp}}}}$$\end{document}Ippp/Issp ratios. Although CO on Pt and Pd should exhibit similar intensities (at high CO coverage), the higher \documentclass[12pt]{minimal}
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\begin{document}$${I_{{\text{ppp}}}}/{I_{{\text{ssp}}}}$$\end{document}Ippp/Issp ratio for Pd (48 vs. 27 on Pt) renders the detection of adsorbed CO in SSP spectra difficult. The presence or absence of CO species in SSP spectra can thus not simply be correlated to tilted or perpendicular CO molecules, respectively. Careful modeling, including not only molecular and interface properties, but also the experimental configuration (incidence angles), is certainly required even for seemingly simple adsorbate–substrate systems.
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Affiliation(s)
- Xia Li
- Institute of Materials Chemistry, TU Wien, 1060 Vienna, Austria
| | - Matteo Roiaz
- Institute of Materials Chemistry, TU Wien, 1060 Vienna, Austria
| | - Verena Pramhaas
- Institute of Materials Chemistry, TU Wien, 1060 Vienna, Austria
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Feng RJ, Li X, Zhang Z, Lu Z, Guo Y. Spectral assignment and orientational analysis in a vibrational sum frequency generation study of DPPC monolayers at the air/water interface. J Chem Phys 2016; 145:244707. [DOI: 10.1063/1.4972564] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Rong-Juan Feng
- Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xia Li
- Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen Zhang
- Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhou Lu
- Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Yuan Guo
- Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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