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Goldsmith ZK, Calegari Andrade MF, Selloni A. Effects of applied voltage on water at a gold electrode interface from ab initio molecular dynamics. Chem Sci 2021; 12:5865-5873. [PMID: 34168811 PMCID: PMC8179682 DOI: 10.1039/d1sc00354b] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Electrode–water interfaces under voltage bias demonstrate anomalous electrostatic and structural properties that are influential in their catalytic and technological applications. Mean-field and empirical models of the electrical double layer (EDL) that forms in response to an applied potential do not capture the heterogeneity that polarizable, liquid-phase water molecules engender. To illustrate the inhomogeneous nature of the electrochemical interface, Born–Oppenheimer ab initio molecular dynamics calculations of electrified Au(111) slabs interfaced with liquid water were performed using a combined explicit–implicit solvent approach. The excess charges localized on the model electrode were held constant and the electrode potentials were computed at frequent simulation times. The electrode potential in each trajectory fluctuated with changes in the atomic structure, and the trajectory-averaged potentials converged and yielded a physically reasonable differential capacitance for the system. The effects of the average applied voltages, both positive and negative, on the structural, hydrogen bonding, dynamical, and vibrational properties of water were characterized and compared to literature where applicable. Controlled-potential simulations of the interfacial solvent dynamics provide a framework for further investigation of more complex or reactive species in the EDL and broadly for understanding electrochemical interfaces in situ. Ab initio molecular dynamics of an aqueous electrode interface reveal the electrostatic, structural, and dynamic effects of quantifiable voltage biases on water.![]()
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Affiliation(s)
| | | | - Annabella Selloni
- Department of Chemistry, Princeton University Princeton NJ 08544 USA
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Goldsmith Z, Secor M, Hammes-Schiffer S. Inhomogeneity of Interfacial Electric Fields at Vibrational Probes on Electrode Surfaces. ACS CENTRAL SCIENCE 2020; 6:304-311. [PMID: 32123749 PMCID: PMC7047426 DOI: 10.1021/acscentsci.9b01297] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Indexed: 05/06/2023]
Abstract
Electric fields control chemical reactivity in a wide range of systems, including enzymes and electrochemical interfaces. Characterizing the electric fields at electrode-solution interfaces is critical for understanding heterogeneous catalysis and associated energy conversion processes. To address this challenge, recent experiments have probed the response of the nitrile stretching frequency of 4-mercaptobenzonitrile (4-MBN) attached to a gold electrode to changes in the solvent and applied electrode potential. Herein, this system is modeled with periodic density functional theory using a multilayer dielectric continuum treatment of the solvent and at constant applied potentials. The impact of the solvent dielectric constant and the applied electrode potential on the nitrile stretching frequency computed with a grid-based method is in qualitative agreement with the experimental data. In addition, the interfacial electrostatic potentials and electric fields as a function of applied potential were calculated directly with density functional theory. Substantial spatial inhomogeneity of the interfacial electric fields was observed, including oscillations in the region of the molecular probe attached to the electrode. These simulations highlight the microscopic inhomogeneity of the electric fields and the role of molecular polarizability at electrode-solution interfaces, thereby demonstrating the limitations of mean-field models and providing insights relevant to the interpretation of vibrational Stark effect experiments.
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Deng Q, Weissmüller J. Electrocapillary coupling during electrosorption. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:10522-10530. [PMID: 25142913 DOI: 10.1021/la501353g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The electrocapillary coupling coefficient, ς, measures the response of the electrode potential, E, to tangential elastic strain at the surface of an electrode. Using dynamic electro-chemo-mechanical analysis, we study ς(E) simultaneously with cyclic voltammetry. The study covers extended potential intervals on Au, Pt, and Pd, including the electrosorption of oxygen species and of hydrogen. The magnitude and sign of ς vary during the scans, and quite generally the graphs of ς(E) emphasize details which are less obvious or missing in the cyclic voltammograms (CVs). Capacitive processes on the clean electrode surfaces exhibit ς < 0, whereas capacitive processes on oxygen-covered surfaces are characterized by ς < 0 on Au but ς > 0 on Pt and Pd. The findings of ς < 0 during the initial stages of oxygen species adsorption and ς > 0 for hydrogen electrosorption agree with the trend that tensile strain makes surfaces more binding for adsorbates. However, the large hysteresis of oxygen electrosorption on all electrodes raises the question: is the exchange current associated with that process sufficient for its measurement by potential response during small cyclic strain?
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Affiliation(s)
- Qibo Deng
- Institut für Werkstoffphysik und Werkstofftechnologie, Technische Universität Hamburg-Harburg , Hamburg, 21073 Germany
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Weissmüller J. Electrocapillarity of Solids and its Impact on Heterogeneous Catalysis. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/9783527680436.ch5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Smetanin M, Deng Q, Weissmüller J. Dynamic electro-chemo-mechanical analysis during cyclic voltammetry. Phys Chem Chem Phys 2011; 13:17313-22. [DOI: 10.1039/c1cp21781j] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Smetanin M, Kramer D, Mohanan S, Herr U, Weissmüller J. Response of the potential of a gold electrode to elastic strain. Phys Chem Chem Phys 2009; 11:9008-12. [DOI: 10.1039/b913448d] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Weissmüller J, Duan H. Cantilever bending with rough surfaces. PHYSICAL REVIEW LETTERS 2008; 101:146102. [PMID: 18851545 DOI: 10.1103/physrevlett.101.146102] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Indexed: 05/26/2023]
Abstract
We show that the response of the curvature of cantilevers to changes in their surface stress depends significantly on the topology of the surface. The origin is the transverse coupling between the out-of-plane and in-plane components of the surface-induced stress. Deliberate structuring of the surface allows the magnitude and even sign of the cantilever response to be tuned, and experiments measuring the surface stress on nominally planar surfaces require a correction when there is roughness.
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Affiliation(s)
- Jörg Weissmüller
- Institut für Nanotechnologie, Forschungszentrum Karlsruhe, Karlsruhe, Germany
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Zangmeister C, Bertocci U, Beauchamp C, Stafford G. In situ stress measurements during the electrochemical adsorption/desorption of self-assembled monolayers. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2007.12.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Smetanin M, Viswanath RN, Kramer D, Beckmann D, Koch T, Kibler LA, Kolb DM, Weissmüller J. Surface stress-charge response of a (111)-textured gold electrode under conditions of weak ion adsorption. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:8561-8567. [PMID: 18616224 DOI: 10.1021/la704067z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We report a cantilever bending investigation into the variation of surface stress, f, with surface charge density, q, for (111)-textured thin films of gold in aqueous NaF and HClO 4. The graphs of f(q) are highly linear, and the surface stress-charge coefficients, d f/d q, are -1.95 V for 7 mM NaF and -2.0 V for 10 mM HClO 4 near the potential of zero charge. These values exceed some previously published experimental data by a factor of 2, but they agree with recent ab initio calculations of the surface stress-charge response of gold in vacuum.
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Affiliation(s)
- M Smetanin
- Forschungszentrum Karlsruhe, Institut fur Nanotechnologie, Karlsruhe, Germany.
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Viswanath R, Kramer D, Weissmüller J. Adsorbate effects on the surface stress–charge response of platinum electrodes. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2007.10.049] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Tabard-Cossa V, Godin M, Burgess IJ, Monga T, Lennox RB, Grütter P. Microcantilever-Based Sensors: Effect of Morphology, Adhesion, and Cleanliness of the Sensing Surface on Surface Stress. Anal Chem 2007; 79:8136-43. [PMID: 17914755 DOI: 10.1021/ac071243d] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The surface stress response of micromechanical cantilever-based sensors was studied as a function of the morphology, adhesion, and cleanliness of the gold sensing surface. Two model systems were investigated: the adsorption of alkanethiol self-assembled monolayers at the gas-solid interface and the potential-controlled adsorption of anions at the liquid-solid interface. The potential-induced surface stress, on a smooth and continuous polycrystalline Au(111)-textured microcantilever in 0.1 M HClO4, is in excellent agreement with macroscopic Au(111) single-crystal electrode results. It is shown that ambient contaminants on the sensing surface dramatically alter the surface stress-potential response. This observation can be misinterpreted as evidence that for polycrystalline Au(111) microcantilever electrodes, surface stress is dominated by surface energy change. Results for anions adsorption on gold are in contrast to the gas-phase model system. We demonstrate that the average grain size of the gold sensing surface strongly influences the magnitude of the surface stress change induced by the adsorption of octanethiol. A 25-fold amplification of the change in surface stress is observed on increasing the average gold grain size of the sensing surface from 90 to 500 nm.
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Trimble T, Tang L, Vasiljevic N, Dimitrov N, van Schilfgaarde M, Friesen C, Thompson CV, Seel SC, Floro JA, Sieradzki K. Anion adsorption induced reversal of coherency strain. PHYSICAL REVIEW LETTERS 2005; 95:166106. [PMID: 16241822 DOI: 10.1103/physrevlett.95.166106] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Indexed: 05/05/2023]
Abstract
Experimental results are presented for stress evolution, in vacuum and electrolyte, for the first monolayer of Cu on Au(111). In electrolyte the monolayer is pseudomorphic and the stress-thickness change is -0.60 N/m, while conventional epitaxy theory predicts a value of +7.76 N/m. In vacuum, the monolayer is incoherent with the underlying gold. Using a combination of first-principles based calculations and molecular dynamic simulations we analyzed these results and demonstrate that in electrolyte, overlayer coherency is maintained owing to anion adsorption.
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Affiliation(s)
- T Trimble
- Ira A. Fulton School of Engineering, Arizona State University, Tempe, 85287-6106, USA
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Weissmüller J, Kramer D. Balance of force at curved solid metal-liquid electrolyte interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:4592-603. [PMID: 16032877 DOI: 10.1021/la047838a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We analyze the simultaneous mechanical and chemical equilibrium at the interface between a fluid electrolyte and a solid conductor in terms of a continuum theory, with attention to surfaces of varying orientation and of arbitrary curvature. On top of the variable which is conjugate to the surface stress, the tangential strain, we introduce an additional degree of freedom for the surface deformation, the surface stretch, to account for the observation of a reversible normal relaxation of the top atomic layer as a function of the electrochemical potential. We derive relations between the materials constants of the surface, for instance, the pressure dependence of the electric potential at constant superficial charge density, and discuss experiments-using cantilevers or porous solids-by which they can be measured.
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Affiliation(s)
- J Weissmüller
- Forschungszentrum Karlsruhe, Institut für Nanotechnologie, Karlsruhe, Germany.
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Viswanath RN, Kramer D, Weissmüller J. Variation of the surface stress-charge coefficient of platinum with electrolyte concentration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:4604-9. [PMID: 16032878 DOI: 10.1021/la0473759] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We report an experimental study of the variation of surface stress with surface charge density for nanoporous Pt immersed in aqueous solutions of NaF of various concentration. As the concentration is reduced, we find initially an increase in the magnitude of the surface stress-charge coefficient, followed by saturation at a value of -1.9 V. Since specific adsorption is expected to be reduced as the solution becomes more dilute, the results support the notion that changes in the bonding at the metal surface play a decisive role in determining the change in the surface stress during double-layer charging.
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Affiliation(s)
- R N Viswanath
- Forschungszentrum Karlsruhe, Institut für Nanotechnologie, Karlsruhe, Germany
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