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Simonenko TL, Bocharova VA, Gorobtsov PY, Simonenko NP, Simonenko EP, Sevastyanov VG, Kuznetsov NT. Features of Hydrothermal Growth of Hierarchical Co3O4 Coatings on Al2O3 Substrates. RUSS J INORG CHEM+ 2020. [DOI: 10.1134/s0036023620090181] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Xie Y, Fu L, Niehaus T, Joly L. Liquid-Solid Slip on Charged Walls: The Dramatic Impact of Charge Distribution. PHYSICAL REVIEW LETTERS 2020; 125:014501. [PMID: 32678629 DOI: 10.1103/physrevlett.125.014501] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/24/2020] [Accepted: 06/12/2020] [Indexed: 05/25/2023]
Abstract
Nanofluidic systems show great promise for applications in energy conversion, where their performance can be enhanced by nanoscale liquid-solid slip. However, efficiency is also controlled by surface charge, which is known to reduce slip. Combining molecular dynamics simulations and analytical developments, we show the dramatic impact of surface charge distribution on the slip-charge coupling. Homogeneously charged graphene exhibits a very favorable slip-charge relation (rationalized with a new theoretical model correcting some weaknesses of the existing ones), leading to giant electrokinetic energy conversion. In contrast, slip is strongly affected on heterogeneously charged surfaces, due to the viscous drag induced by counterions trapped on the surface. In that case slip should depend on the detailed physical chemistry of the interface controlling the fraction of bound ions. Our numerical results and theoretical models provide new fundamental insight into the molecular mechanisms of liquid-solid slip, and practical guidelines for searching new functional interfaces with optimal energy conversion properties, e.g., for blue energy or waste heat harvesting.
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Affiliation(s)
- Yanbo Xie
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xian, 710072, China
| | - Li Fu
- Univ Lyon, Ecole Centrale de Lyon, Laboratoire de Tribologie et Dynamique des Systèmes, UMR 5513, 36 avenue Guy de Collongue, 69134 Ecully Cedex, France
| | - Thomas Niehaus
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, Villeurbanne, France
| | - Laurent Joly
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, Villeurbanne, France
- Institut Universitaire de France (IUF), 1 rue Descartes, 75005 Paris, France
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Gauthier JA, Chen LD, Bajdich M, Chan K. Implications of the fractional charge of hydroxide at the electrochemical interface. Phys Chem Chem Phys 2020; 22:6964-6969. [PMID: 32186292 DOI: 10.1039/c9cp05952k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Rational design of materials that efficiently convert electrical energy into chemical bonds will ultimately depend on a thorough understanding of the electrochemical interface at the atomic level. Towards this goal, the use of density functional theory (DFT) at the generalized gradient approximation (GGA) level has been applied widely in the past 15 years. In the calculation of electrochemical reaction energetics using GGA-DFT, it is frequently implicitly assumed that ions in the Helmholtz plane have unit charge. However, the ion charge is observed to be fractional near the interface through both a capacitor model and through Bader charge partitioning. In this work, we show that this spurious charge transfer can be effectively mitigated by continuum charging of the electrolyte. We then show that, similar to hydronium, the observed fractional charge of hydroxide is not due to a GGA level self-interaction error, as the partial charge is observed even when using hybrid level exchange-correlation functionals.
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Affiliation(s)
- Joseph A Gauthier
- SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, California 94305, USA
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Smirnov KS. Structure and sum-frequency generation spectra of water on uncharged Q 4 silica surfaces: a molecular dynamics study. Phys Chem Chem Phys 2020; 22:2033-2045. [PMID: 31904065 DOI: 10.1039/c9cp05765j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The structural characteristics and sum-frequency generation (SFG) spectra of water near neutral Q4 silica surfaces were investigated by molecular dynamics simulations. The interactions of water molecules with atoms of the solid were described by different potential models, in particular by the CLAYFF [Cygan et al., J. Phys. Chem. B, 2004, 108, 1255] and INTERFACE [Heinz et al. Langmuir, 2013, 29, 1754] force fields. The calculations of the contact angle of water have shown that the silica surface modeled with CLAYFF behaves as macroscopically hydrophilic, in contrast to the surface described with the INTERFACE model. The hydrophilicity of CLAYFF stems from too attractive electrostatic surface-water interactions. Regardless of the surface's affinity for water, the aqueous phase has a layered structure in the direction perpendicular to the surface with density fluctuations decaying within a distance of 10 Å from the surface. The orientational ordering of H2O molecules was found to be more short-range than the density fluctuations, especially for the hydrophobic surfaces. Modeling the SFG spectra has shown that the spectra of all studied hydrophobic silica-water interfaces are similar and have features in common with the spectrum of the water-vapor interface. The spectra fairly agree with experimental results obtained for the silica-water interface at low pH conditions [Myalitsin et al., J. Phys. Chem. C, 2016, 120, 9357]. The spectral response for the hydrophobic interface was computed to primarily arise from the topmost molecules of the first layer of interfacial water. In contrast, the SFG signal from the hydrophilic silica-water interface is accumulated over a greater distance extending for several water layers due to more long-range perturbation of the structure by the surface.
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Affiliation(s)
- Konstantin S Smirnov
- Univ. Lille, CNRS, UMR 8516 - LASIR - Laboratoire de Spectrochimie Infrarouge et Raman, F-59000 Lille, France.
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Creazzo F, Pezzotti S, Bougueroua S, Serva A, Sponer J, Saija F, Cassone G, Gaigeot MP. Enhanced conductivity of water at the electrified air–water interface: a DFT-MD characterization. Phys Chem Chem Phys 2020; 22:10438-10446. [DOI: 10.1039/c9cp06970d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
DFT-based molecular dynamics simulations of the electrified air–liquid water interface are presented, where a homogeneous field is applied parallel to the surface plane (i.e. parallel to the 2D-HBonded-Network/2DN).
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Affiliation(s)
| | | | | | - Alessandra Serva
- Sorbonne Université
- CNRS
- Physico-chimie des électrolytes et nano-systèmes interfaciaux
- PHENIX
- Paris
| | - Jiri Sponer
- Institute of Biophysics of the Czech Academy of Sciences
- 61265 Brno
- Czech Republic
| | | | - Giuseppe Cassone
- Institute of Biophysics of the Czech Academy of Sciences
- 61265 Brno
- Czech Republic
- CNR-IPCF
- 98158 Messina
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Zhang C, Hutter J, Sprik M. Coupling of Surface Chemistry and Electric Double Layer at TiO 2 Electrochemical Interfaces. J Phys Chem Lett 2019; 10:3871-3876. [PMID: 31241948 DOI: 10.1021/acs.jpclett.9b01355] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Surfaces of metal oxides at working conditions are usually electrified because of the acid-base chemistry. The charged interface compensated with counterions forms the so-called electric double layer. The coupling of surface chemistry and the electric double layer is considered to be crucial but is poorly understood because of the lack of information at the atomistic scale. Here, we used the latest development in density functional theory-based finite-field molecular dynamics simulation to investigate the pH dependence of the Helmholtz capacitance at electrified rutile TiO2(110)-NaCl electrolyte interfaces. It is found that, because of competing forces from surface adsorption and from the electric double layer, water molecules have a stronger structural fluctuation at high pH, and this leads to a much larger capacitance. It is also seen that interfacial proton transfers at low pH increase significantly the capacitance value. These findings elucidate the microscopic origin of the same trend observed in titration experiments.
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Affiliation(s)
- Chao Zhang
- Department of Chemistry-Ångström Laboratory , Uppsala University , Lägerhyddsvägen 1 , BOX 538, 75121 Uppsala , Sweden
| | - Jürg Hutter
- Institut für Chemie , Universität Zürich , Winterthurerstrasse 190 , CH-8057 Zürich , Switzerland
| | - Michiel Sprik
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
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Lian T, Koper MTM, Reuter K, Subotnik JE. Special Topic on Interfacial Electrochemistry and Photo(electro)catalysis. J Chem Phys 2019; 150:041401. [PMID: 30709260 DOI: 10.1063/1.5088351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Interfacial electrochemistry and photo(electro)catalysis are key processes that convert the energy of photons or electrons to chemical bonds in many energy conversion and storage technologies. Achieving a molecular level understanding of the fundamental interfacial structure, energetics, dynamics, and reaction mechanisms that govern these processes represents a broad frontier for chemical physics and physical chemistry. This Special Topic contains a collection of articles that range from the development of new experimental and computational techniques to the novel application of those techniques for mechanistic studies, as the principal investigators seek a fundamental molecular understanding of both electrode/electrolyte interfaces and the relevant electrocatalytic, photocatalytic, and photoelectrochemical reactions taking place thereabout. Altogether, this collection of articles captures the current state of this very active, frontier research field and highlights the current and remaining key scientific challenges and opportunities.
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Affiliation(s)
- Tianquan Lian
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
| | - Marc T M Koper
- Leiden Institute of Chemistry, Leiden University, 2300 RA Leiden, The Netherlands
| | - Karsten Reuter
- Chair for Theoretical Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany
| | - Joseph E Subotnik
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Zhang D, Zhang J, Gong L, Zhu Y, Zhang L, Xia Z. Graphene-covered transition metal halide molecules as efficient and durable electrocatalysts for oxygen reduction and evolution reactions. Phys Chem Chem Phys 2019; 21:23094-23101. [DOI: 10.1039/c9cp04618f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Graphene-covered halides are designed as durable and efficient electrocatalysts in acid media. A design principle has been established through the DFT calculations, from which the best catalysts could be predicted for fuel cells.
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Affiliation(s)
- Detao Zhang
- College of Chemical Engineering
- Beijing University of Chemical Technology
- Beijing
- China
| | - Jing Zhang
- School of Materials Science and Engineering
- Northwestern Polytechnical University
- Xi’an
- China
| | - Lele Gong
- College of Chemical Engineering
- Beijing University of Chemical Technology
- Beijing
- China
| | - Yonghao Zhu
- College of Chemical Engineering
- Beijing University of Chemical Technology
- Beijing
- China
| | - Lipeng Zhang
- College of Chemical Engineering
- Beijing University of Chemical Technology
- Beijing
- China
| | - Zhenhai Xia
- Department of Materials Science and Engineering, University of North Texas
- Denton
- USA
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