1
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Liang X, Zhou Y, Zhu W, Xu WW, Francisco JS, Zeng XC, Zhao W. Formation of compounds with diverse polyelectrolyte morphologies and nonlinear ion conductance in a two-dimensional nanofluidic channel. Chem Sci 2024; 15:8170-8180. [PMID: 38817585 PMCID: PMC11134406 DOI: 10.1039/d4sc01071j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/29/2024] [Indexed: 06/01/2024] Open
Abstract
Aqueous electrolytes subjected to angstrom-scale confinement have recently attracted increasing interest because of their distinctive structural and transport properties, as well as their promising applicability in bioinspired nanofluidic iontronics and ion batteries. Here, we performed microsecond-scale molecular dynamics simulations, which provided evidence of nonlinear ionic conductance under an external lateral electric field due to the self-assembly of cations and anions with diverse polyelectrolyte morphologies (e.g., extremely large ion clusters) in aqueous solutions within angstrom-scale slits. Specifically, we found that the cations and anions of Li2SO4 and CaSO4 formed chain-like polyelectrolyte structures, whereas those of Na2SO4 and MgSO4 predominantly formed a monolayer of hydrated salt. Additionally, the cations and anions of K2SO4 assembled into a hexagonal anhydrous ionic crystal. These ion-dependent diverse polyelectrolyte morphologies stemmed from the enhanced Coulomb interactions, weakened hydration and steric constraints within the angstrom-scale slits. More importantly, once the monolayer hydrated salt or ionic crystal structure was formed, the field-induced ion current exhibited an intriguing gating effect at a low field strength. This abnormal ion transport was attributed to the concerted movement of cations and anions within the solid polyelectrolytes, leading to the suppression of ion currents. When the electric field exceeded a critical strength, however, the ion current surged rapidly due to the dissolution of many cations and anions within a few nanoseconds in the aqueous solution.
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Affiliation(s)
- Xiaoying Liang
- Department of Physics, Ningbo University Ningbo Zhejiang 315211 China
| | - Yanan Zhou
- School of Material Science and Chemical Engineering, Institute of Mass Spectrometry, Ningbo University Ningbo 315211 China
| | - Weiduo Zhu
- Department of Physics, Hefei University of Technology Hefei Anhui 230009 China
| | - Wen Wu Xu
- Department of Physics, Ningbo University Ningbo Zhejiang 315211 China
| | - Joseph S Francisco
- Department of Chemistry, University of Pennsylvania Philadelphia Pennsylvania 19104 USA
| | - Xiao Cheng Zeng
- Department of Materials Science & Engineering, City University of Hong Kong Kowloon 999077 Hong Kong China
| | - Wenhui Zhao
- Department of Physics, Ningbo University Ningbo Zhejiang 315211 China
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2
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Kastlunger G, Vijay S, Chen X, Sharma S, Peterson A. On the Thermodynamic Equivalence of Grand Canonical, Infinite-Size, and Capacitor-Based Models in First-Principle Electrochemistry. Chemphyschem 2024; 25:e202300950. [PMID: 38511569 DOI: 10.1002/cphc.202300950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 02/27/2024] [Indexed: 03/22/2024]
Abstract
First principles-based computational and theoretical methods are constantly evolving trying to overcome the many obstacles towards a comprehensive understanding of electrochemical processes on an atomistic level. One of the major challenges has been the determination of reaction energetics under a constant potential. Here, a theoretical framework was proposed applying standard electronic structure methods and extrapolating to the infinite-cell size limit where reactions do not alter the potential. Today, electronically grand canonical modifications to electronic structure methods, holding the potential constant by varying the number of electrons in a finite simulation cell, become increasingly popular. In this perspective, we show that these two schemes are thermodynamically equivalent. Further, we link these methods to capacitive models of the interface, in the limit that the capacitance of the charging components (whether continuum or atomistic) are equal and invariant along the reaction pathway. We benchmark the three approaches with an example of alkali cation adsorption on Pt(111) showing that all three approaches converge in the cases of Li, Na and K. For Cs, however, strong deviation from the ideal conditions leads to a spread in the respective results. We discuss the latter by highlighting the cases of broken equivalence and assumptions among the approaches.
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Affiliation(s)
- Georg Kastlunger
- Catalysis Theory Center, Department of Physics, Technical University of Denmark, Fysikvej, 2800, Kongens Lyngby, Denmark
| | - Sudarshan Vijay
- Catalysis Theory Center, Department of Physics, Technical University of Denmark, Fysikvej, 2800, Kongens Lyngby, Denmark
| | - Xi Chen
- School of Engineering, Brown University, Hope Street, Providence, RI, USA
| | - Shubham Sharma
- School of Engineering, Brown University, Hope Street, Providence, RI, USA
| | - Andrew Peterson
- School of Engineering, Brown University, Hope Street, Providence, RI, USA
- Department of Energy Conversion and Storage, Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark
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3
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Mohandas N, Bawari S, Shibuya JJT, Ghosh S, Mondal J, Narayanan TN, Cuesta A. Understanding electrochemical interfaces through comparing experimental and computational charge density-potential curves. Chem Sci 2024; 15:6643-6660. [PMID: 38725490 PMCID: PMC11077530 DOI: 10.1039/d4sc00746h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/21/2024] [Indexed: 05/12/2024] Open
Abstract
Electrode-electrolyte interfaces play a decisive role in electrochemical charge accumulation and transfer processes. Theoretical modelling of these interfaces is critical to decipher the microscopic details of such phenomena. Different force field-based molecular dynamics protocols are compared here in a view to connect calculated and experimental charge density-potential relationships. Platinum-aqueous electrolyte interfaces are taken as a model. The potential of using experimental charge density-potential curves to transform cell voltage into electrode potential in force-field molecular dynamics simulations, and the need for that purpose of developing simulation protocols that can accurately calculate the double-layer capacitance, are discussed.
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Affiliation(s)
- Nandita Mohandas
- Tata Institute of Fundamental Research-Hyderabad Hyderabad 500046 India
- Advanced Centre for Energy and Sustainability (ACES), School of Natural and Computing Sciences, University of Aberdeen AB24 3UE Aberdeen Scotland UK
| | - Sumit Bawari
- Tata Institute of Fundamental Research-Hyderabad Hyderabad 500046 India
| | - Jani J T Shibuya
- Advanced Centre for Energy and Sustainability (ACES), School of Natural and Computing Sciences, University of Aberdeen AB24 3UE Aberdeen Scotland UK
| | - Soumya Ghosh
- Tata Institute of Fundamental Research-Hyderabad Hyderabad 500046 India
| | - Jagannath Mondal
- Tata Institute of Fundamental Research-Hyderabad Hyderabad 500046 India
| | | | - Angel Cuesta
- Advanced Centre for Energy and Sustainability (ACES), School of Natural and Computing Sciences, University of Aberdeen AB24 3UE Aberdeen Scotland UK
- Centre for Energy Transition, University of Aberdeen AB24 3FX Aberdeen Scotland UK
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4
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Choudhary A, Ho TA. Confinement-induced clustering of H 2 and CO 2 gas molecules in hydrated nanopores. Phys Chem Chem Phys 2024; 26:10506-10514. [PMID: 38380805 DOI: 10.1039/d3cp06024a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Gas molecule clustering within nanopores holds significance in the fields of nanofluidics, biology, gas adsorption/desorption, and geological gas storage. However, the intricate roles of nanoconfinement and surface chemistry that govern the formation of gas clusters remain inadequately explored. In this study, through free energy calculation in molecular simulations, we systematically compared the tendencies of H2 and CO2 molecules to aggregate within hydrated hydrophobic pyrophyllite and hydrophilic gibbsite nanopores. The results indicate that nanoconfinement enhances gas dimer formation in the nanopores, irrespective of surface chemistry. However, surface hydrophilicity prohibits the formation of gas clusters larger than dimers, while large gas clusters form easily in hydrophobic nanopores. Despite H2 and CO2 both being non-polar, the larger quadrupole moment of CO2 leads to a stronger preference for dimer/cluster formation compared to H2. Our results also indicate that gases prefer to enter the nanopores as individual molecules, but exit the nanopores as dimers/clusters. This investigation provides a mechanistic understanding of gas cluster formation within nanopores, which is relevant to various applications, including geological gas storage.
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Affiliation(s)
- Aditya Choudhary
- Geochemistry Department, Sandia National Laboratories, Albuquerque, NM 87185, USA.
| | - Tuan A Ho
- Geochemistry Department, Sandia National Laboratories, Albuquerque, NM 87185, USA.
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5
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Dufils T, Schran C, Chen J, Geim AK, Fumagalli L, Michaelides A. Origin of dielectric polarization suppression in confined water from first principles. Chem Sci 2024; 15:516-527. [PMID: 38179530 PMCID: PMC10763014 DOI: 10.1039/d3sc04740g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 11/23/2023] [Indexed: 01/06/2024] Open
Abstract
It has long been known that the dielectric constant of confined water should be different from that in bulk. Recent experiments have shown that it is vanishingly small, however the origin of the phenomenon remains unclear. Here we used ab initio molecular dynamics simulations (AIMD) and AIMD-trained machine-learning potentials to understand water's structure and electronic properties underpinning this effect. For the graphene and hexagonal boron-nitride substrates considered, we find that it originates in the spontaneous anti-parallel alignment of the water dipoles in the first two water layers near the solid interface. The interfacial layers exhibit net ferroelectric ordering, resulting in an overall anti-ferroelectric arrangement of confined water. Together with constrained hydrogen-bonding orientations, this leads to much reduced out-of-plane polarization. Furthermore, we directly contrast AIMD and simple classical force-field simulations, revealing important differences. This work offers insight into a property of water that is critical in modulating surface forces, the electric-double-layer formation and molecular solvation, and shows a way to compute it.
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Affiliation(s)
- T Dufils
- Department of Physics and Astronomy, University of Manchester Manchester M13 9PL UK
- National Graphene Institute, University of Manchester Manchester M13 9PL UK
| | - C Schran
- Cavendish Laboratory, Department of Physics, University of Cambridge Cambridge CB3 0HE UK
- Lennard-Jones Centre, University of Cambridge Trinity Ln Cambridge CB2 1TN UK
| | - J Chen
- School of Physics, Peking University Beijing 100871 China
| | - A K Geim
- Department of Physics and Astronomy, University of Manchester Manchester M13 9PL UK
- National Graphene Institute, University of Manchester Manchester M13 9PL UK
| | - L Fumagalli
- Department of Physics and Astronomy, University of Manchester Manchester M13 9PL UK
- National Graphene Institute, University of Manchester Manchester M13 9PL UK
| | - A Michaelides
- Lennard-Jones Centre, University of Cambridge Trinity Ln Cambridge CB2 1TN UK
- Yusuf Hamied Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
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6
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Bergmann N, Hörmann NG, Reuter K. Ab Initio-Based Modeling of Thermodynamic Cyclic Voltammograms: A Benchmark Study on Ag(100) in Bromide Solutions. J Chem Theory Comput 2023; 19:8815-8825. [PMID: 38038493 PMCID: PMC10720351 DOI: 10.1021/acs.jctc.3c00957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/11/2023] [Accepted: 11/17/2023] [Indexed: 12/02/2023]
Abstract
Experimental cyclic voltammograms (CVs) measured in the slow scan rate limit can be entirely described in terms of the thermodynamic equilibrium quantities of the electrified solid-liquid interface. They correspondingly serve as an important benchmark for the quality of first-principles calculations of interfacial thermodynamics. Here, we investigate the partially drastic approximations made presently in computationally efficient calculations for the well-defined showcase of an Ag(100) model electrode in Br-containing electrolytes, where the nontrivial part of the CV stems from the electrosorption of Br ions. We specifically study the entanglement of common approximations in the treatment of solvation and field effects, as well as in the way macroscopic averages of the two key quantities, namely, the potential-dependent adsorbate coverage and electrosorption valency, are derived from the first-principles energetics. We demonstrate that the combination of energetics obtained within an implicit solvation model and a perturbative second order account of capacitive double layer effects with a constant-potential grand-canonical Monte Carlo sampling of the adsorbate layer provides an accurate description of the experimental CV. However, our analysis also shows that error cancellation at lower levels of theory may equally lead to good descriptions even though key underlying physics such as the disorder-order transition of the Br adlayer at increasing coverages is inadequately treated.
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Affiliation(s)
- Nicolas Bergmann
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Nicolas G. Hörmann
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Karsten Reuter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
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7
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Beinlich SD, Kastlunger G, Reuter K, Hörmann NG. Controlled Electrochemical Barrier Calculations without Potential Control. J Chem Theory Comput 2023; 19:8323-8331. [PMID: 37933878 PMCID: PMC10688182 DOI: 10.1021/acs.jctc.3c00836] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/19/2023] [Accepted: 10/23/2023] [Indexed: 11/08/2023]
Abstract
The knowledge of electrochemical activation energies under applied potential conditions is a prerequisite for understanding catalytic activity at electrochemical interfaces. Here, we present a new set of methods that can compute electrochemical barriers with accuracy comparable to that of constant potential grand canonical approaches, without the explicit need for a potentiostat. Instead, we Legendre transform a set of constant charge, canonical reaction paths. Additional straightforward approximations offer the possibility to compute electrochemical barriers at a fraction of computational cost and complexity, and the analytical inclusion of geometric response highlights the importance of incorporating electronic as well as the geometric degrees of freedom when evaluating electrochemical barriers.
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Affiliation(s)
- Simeon D. Beinlich
- Fritz-Haber-Institut
der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
- Technical
University of Munich, Lichtenbergstraße 4, 85747 Garching, Germany
| | - Georg Kastlunger
- Technical
University of Denmark, Fysikvej 311, 2800 Kongens Lyngby, Denmark
| | - Karsten Reuter
- Fritz-Haber-Institut
der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Nicolas G. Hörmann
- Fritz-Haber-Institut
der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
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8
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Ruiz-Barragan S, Forbert H, Marx D. Anisotropic pressure effects on nanoconfined water within narrow graphene slit pores. Phys Chem Chem Phys 2023; 25:28119-28129. [PMID: 37818616 DOI: 10.1039/d3cp01687k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
There is an increasing interest toward disclosing and explaining confinement effects on liquids, such as water or aqueous solutions, in slit pore setups. Particularly puzzling are the changes of physical and chemical properties in the nanoconfinement regime where no bulk-like water phase exists between the two interfacial water layers such that the density profile across the slit pore becomes highly stratified, ultimately leading to bilayer and monolayer water. These changes must be quantified with respect to some meaningful reference state of water, the most natural one being bulk water at the same pressure and temperature conditions. However, bulk water is a homogeneous liquid with isotropic properties, whereas water confined in slit pores is inhomogeneous, implying anisotropic properties as described by the perpendicular and parallel components of the respective tensors. In the case of pressure, the inhomogeneous nature of the setup results in a well-defined difference between the perpendicular and parallel pressure tensor components that is uniquely determined by the interfacial tension being a thermodynamic property. For bilayer water constrained in graphene slit pores that are only about 1 nm wide, we demonstrate that there exists a thermodynamic point where the pressure tensor of the inhomogeneous fluid, nanoconfined water, is effectively isotopic and the pressure is thus scalar as in the homogeneous fluid, bulk water. This specific point of vanishing effective interfacial tension is proposed to serve as a well-defined reference state to compare the properties of nanoconfined liquids to those of the corresponding bulk liquid at the same (isotropic) pressure and temperature conditions. In future work, this idea could be applied to assess confinement effects on chemical reactivity in aqueous solutions as well as to other nanoconfined liquids in other pores such as layered minerals.
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Affiliation(s)
- Sergi Ruiz-Barragan
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany.
| | - Harald Forbert
- Center for Solvation Science ZEMOS, Ruhr - Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany.
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9
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Li P, Jiao Y, Huang J, Chen S. Electric Double Layer Effects in Electrocatalysis: Insights from Ab Initio Simulation and Hierarchical Continuum Modeling. JACS AU 2023; 3:2640-2659. [PMID: 37885580 PMCID: PMC10598835 DOI: 10.1021/jacsau.3c00410] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 09/02/2023] [Accepted: 09/06/2023] [Indexed: 10/28/2023]
Abstract
Structures of the electric double layer (EDL) at electrocatalytic interfaces, which are modulated by the material properties, the electrolyte characteristics (e.g., the pH, the types and concentrations of ions), and the electrode potential, play crucial roles in the reaction kinetics. Understanding the EDL effects in electrocatalysis has attracted substantial research interest in recent years. However, the intrinsic relationships between the specific EDL structures and electrocatalytic kinetics remain poorly understood, especially on the atomic scale. In this Perspective, we briefly review the recent advances in deciphering the EDL effects mainly in hydrogen and oxygen electrocatalysis through a multiscale approach, spanning from the atomistic scale simulated by ab initio methods to the macroscale by a hierarchical approach. We highlight the importance of resolving the local reaction environment, especially the local hydrogen bond network, in understanding EDL effects. Finally, some of the remaining challenges are outlined, and an outlook for future developments in these exciting frontiers is provided.
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Affiliation(s)
- Peng Li
- Hubei
Key Laboratory of Electrochemical Power Sources, College of Chemistry
and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Yuzhou Jiao
- Hubei
Key Laboratory of Electrochemical Power Sources, College of Chemistry
and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Jun Huang
- Institute
of Energy and Climate Research, IEK-13: Theory and Computation of
Energy Materials, Forschungszentrum Jülich
GmbH, 52425 Jülich, Germany
- Theory
of Electrocatalytic Interfaces, Faculty of Georesources and Materials
Engineering, RWTH Aachen University, 52062 Aachen, Germany
| | - Shengli Chen
- Hubei
Key Laboratory of Electrochemical Power Sources, College of Chemistry
and Molecular Sciences, Wuhan University, Wuhan 430072, China
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10
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Erbe A, Tesch MF, Rüdiger O, Kaiser B, DeBeer S, Rabe M. Operando studies of Mn oxide based electrocatalysts for the oxygen evolution reaction. Phys Chem Chem Phys 2023; 25:26958-26971. [PMID: 37585177 DOI: 10.1039/d3cp02384b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2023]
Abstract
Inspired by photosystem II (PS II), Mn oxide based electrocatalysts have been repeatedly investigated as catalysts for the electrochemical oxygen evolution reaction (OER), the anodic reaction in water electrolysis. However, a comparison of the conditions in biological OER catalysed by the water splitting complex CaMn4Ox with the requirements for an electrocatalyst for industrially relevant applications reveals fundamental differences. Thus, a systematic development of artificial Mn-based OER catalysts requires both a fundamental understanding of the catalytic mechanisms as well as an evaluation of the practicality of the system for industrial scale applications. Experimentally, both aspects can be approached using in situ and operando methods including spectroscopy. This paper highlights some of the major challenges common to different operando investigation methods and recent insights gained with them. To this end, vibrational spectroscopy, especially Raman spectroscopy, absorption techniques in the bandgap region and operando X-ray spectroelectrochemistry (SEC), both in the hard and soft X-ray regime are particularly focused on here. Technical challenges specific to each method are discussed first, followed by challenges that are specific to Mn oxide based systems. Finally, recent in situ and operando studies are reviewed. This analysis shows that despite the technical and Mn specific challenges, three specific key features are common to most of the studied systems with significant OER activity: structural disorder, Mn oxidation states between III and IV, and the appearance of layered birnessite phases in the active regime.
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Affiliation(s)
- Andreas Erbe
- Department of Materials Science and Engineering, NTNU, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Marc Frederic Tesch
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany.
| | - Olaf Rüdiger
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany.
| | - Bernhard Kaiser
- Surface Science Laboratory, Department of Materials- and Earth Sciences, Technical University Darmstadt, Otto-Berndt-Str. 3, 64287 Darmstadt, Germany
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany.
| | - Martin Rabe
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany.
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11
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Ilgen AG, Kabengi N, Smith JG, Sanchez KMM. Ion solvation as a predictor of lanthanide adsorption structures and energetics in alumina nanopores. Commun Chem 2023; 6:172. [PMID: 37607981 PMCID: PMC10444809 DOI: 10.1038/s42004-023-00978-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 08/08/2023] [Indexed: 08/24/2023] Open
Abstract
Adsorption reactions at solid-water interfaces define elemental fate and transport and enable contaminant clean-up, water purification, and chemical separations. For nanoparticles and nanopores, nanoconfinement may lead to unexpected and hard-to-predict products and energetics of adsorption, compared to analogous unconfined surfaces. Here we use X-ray absorption fine structure spectroscopy and operando flow microcalorimetry to determine nanoconfinement effects on the energetics and local coordination environment of trivalent lanthanides adsorbed on Al2O3 surfaces. We show that the nanoconfinement effects on adsorption become more pronounced as the hydration free energy, ΔGhydr, of a lanthanide decreases. Neodymium (Nd3+) has the least exothermic ΔGhydr (-3336 kJ·mol-1) and forms mostly outer-sphere complexes on unconfined Al2O3 surfaces but shifts to inner-sphere complexes within the 4 nm Al2O3 pores. Lutetium (Lu3+) has the most exothermic ΔGhydr (-3589 kJ·mol-1) and forms inner-sphere adsorption complexes regardless of whether Al2O3 surfaces are nanoconfined. Importantly, the energetics of adsorption is exothermic in nanopores only, and becomes endothermic with increasing surface coverage. Changes to the energetics and products of adsorption in nanopores are ion-specific, even within chemically similar trivalent lanthanide series, and can be predicted by considering the hydration energies of adsorbing ions.
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Affiliation(s)
- Anastasia G Ilgen
- Geochemistry Department, Sandia National Laboratories, 1515 Eubank Boulevard SE, Albuquerque, NM, 87123, USA.
| | - Nadine Kabengi
- Department of Geosciences, Georgia State University, 24 Peachtree Center Avenue NE, Atlanta, GA, 30303, USA
| | - Jacob G Smith
- Geochemistry Department, Sandia National Laboratories, 1515 Eubank Boulevard SE, Albuquerque, NM, 87123, USA
| | - Kadie M M Sanchez
- Geochemistry Department, Sandia National Laboratories, 1515 Eubank Boulevard SE, Albuquerque, NM, 87123, USA
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12
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El‐Zoka AA, Stephenson LT, Kim S, Gault B, Raabe D. The Fate of Water in Hydrogen-Based Iron Oxide Reduction. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300626. [PMID: 37290039 PMCID: PMC10460863 DOI: 10.1002/advs.202300626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 05/07/2023] [Indexed: 06/10/2023]
Abstract
Gas-solid reactions are important for many redox processes that underpin the energy and sustainability transition. The specific case of hydrogen-based iron oxide reduction is the foundation to render the global steel industry fossil-free, an essential target as iron production is the largest single industrial emitter of carbon dioxide. This perception of gas-solid reactions has not only been limited by the availability of state-of-the-art techniques which can delve into the structure and chemistry of reacted solids, but one continues to miss an important reaction partner that defines the thermodynamics and kinetics of gas phase reactions: the gas molecules. In this investigation, cryogenic-atom probe tomography is used to study the quasi in situ evolution of iron oxide in the solid and gas phases of the direct reduction of iron oxide by deuterium gas at 700°C. So far several unknown atomic-scale characteristics are observed, including, D2 accumulation at the reaction interface; formation of a core (wüstite)-shell (iron) structure; inbound diffusion of D through the iron layer and partitioning of D among phases and defects; outbound diffusion of oxygen through the wüstite and/or through the iron to the next free available inner/outer surface; and the internal formation of heavy nano-water droplets at nano-pores.
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Affiliation(s)
- Ayman A. El‐Zoka
- Max‐Planck‐Institut für EisenforschungMax‐Planck‐Strasse 140237DüsseldorfGermany
- Department of MaterialsRoyal School of MinesImperial CollegeLondonSW7 2AZUK
| | - Leigh T. Stephenson
- Max‐Planck‐Institut für EisenforschungMax‐Planck‐Strasse 140237DüsseldorfGermany
| | - Se‐Ho Kim
- Max‐Planck‐Institut für EisenforschungMax‐Planck‐Strasse 140237DüsseldorfGermany
- Department of Materials Science and EngineeringKorea UniversitySeoul02841Republic of Korea
| | - Baptiste Gault
- Max‐Planck‐Institut für EisenforschungMax‐Planck‐Strasse 140237DüsseldorfGermany
- Department of MaterialsRoyal School of MinesImperial CollegeLondonSW7 2AZUK
| | - Dierk Raabe
- Max‐Planck‐Institut für EisenforschungMax‐Planck‐Strasse 140237DüsseldorfGermany
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13
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Xia Z, Xiao H. Grand Canonical Ensemble Modeling of Electrochemical Interfaces Made Simple. J Chem Theory Comput 2023. [PMID: 37399292 DOI: 10.1021/acs.jctc.3c00237] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
Grand canonical ensemble (GCE) modeling of electrochemical interfaces, in which the electrochemical potential is converged to a preset constant, is essential for understanding electrochemistry and electrocatalysis at the electrodes. However, it requires developing efficient and robust algorithms to perform practical and effective GCE modeling with density functional theory (DFT) calculations. Herein, we developed an efficient and robust fully converged constant-potential (FCP) algorithm based on Newton's method and a polynomial fitting to calculate the necessary derivative for DFT calculations. We demonstrated with the constant-potential geometry optimization and Born-Oppenheimer molecular dynamics (BOMD) calculations that our FCP algorithm is resistant to the numerical instability that plagues other algorithms, and it delivers efficient convergence to the preset electrochemical potential and renders accurate forces for updating the nuclear positions of an electronically open system, outperforming other algorithms. The implementation of our FCP algorithm enables flexibility in using various computational codes and versatility in performing advanced tasks including the constant-potential enhanced-sampling BOMD simulations that we showcased with the modeling of the electrochemical hydrogenation of CO, and it is thus expected to find a wide spectrum of applications in the modeling of chemistry at electrochemical interfaces.
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Affiliation(s)
- Zhaoming Xia
- Department of Chemistry, Tsinghua University, Beijing 100084, China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Hai Xiao
- Department of Chemistry, Tsinghua University, Beijing 100084, China
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14
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Pivnic K, de Souza JP, Kornyshev AA, Urbakh M, Bazant MZ. Orientational Ordering in Nano-confined Polar Liquids. NANO LETTERS 2023. [PMID: 37285463 DOI: 10.1021/acs.nanolett.3c00927] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Water and other polar liquids exhibit nanoscale structuring near charged interfaces. When a polar liquid is confined between two charged surfaces, the interfacial solvent layers begin to overlap, resulting in solvation forces. Here, we perform molecular dynamics simulations of polar liquids with different dielectric constants and molecular shapes and sizes confined between charged surfaces, demonstrating strong orientational ordering in the nanoconfined liquids. To rationalize the observed structures, we apply a coarse-grained continuum theory that captures the orientational ordering and solvation forces of those liquids. Our findings reveal the subtle behavior of different nanoconfined polar liquids and establish a simple law for the decay length of the interfacial orientations of the solvents, which depends on their molecular size and polarity. These insights shed light on the nature of solvation forces, which are important in colloid and membrane science, scanning probe microscopy, and nano-electrochemistry.
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Affiliation(s)
- Karina Pivnic
- School of Chemistry, The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
| | - J Pedro de Souza
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alexei A Kornyshev
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ 2AZ London, United Kingdom
- Thomas Young Centre for Theory and Simulation of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Michael Urbakh
- School of Chemistry, The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Martin Z Bazant
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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15
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Wang D, Lippmann M, Gäding J, Ehnes A, Novikov D, Meißner R, Seeck OH. Orientation order of a nonpolar molecular fluid compressed into a nanosmall space. NANOSCALE 2023; 15:8019-8028. [PMID: 37070420 DOI: 10.1039/d2nr06330a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The ordering structures of non-polar carbon tetrachloride liquid compressed to nano-scales between parallel substrates is studied in this work. The theoretical considerations show that the potential well formed by the confined parallel substrates induces orientational ordering of non-polar molecules. Through molecular dynamic (MD) simulations, the relations between various ordered structures of a non-polar liquid (carbon tetrachloride) and the confined gap size are demonstrated. The density distribution shows that the confinement does affect the ordering modes and induces an orientational ordering of molecules at the solid-liquid interface under extreme confinement conditions. This molecular orientation suggested from the theoretical model and MD simulation is directly supported by the experimental studies for the first time. The X-ray reflectivity data reveal a strong layering effect with splitting of the density profile in C and Cl-rich sublayers. The investigation shows that the liquid structure factor in confinement has a characteristic length similar to the short-range ordering in bulk, but the confined structure is strongly influenced by the surface potential and the interface properties. This introduces preferred molecular orientation and ordering which are not favorable in the bulk phase. As the orientational ordering is closely related to crystallization, our results provide a new perspective to control the crystallization in nano-confined space by compression.
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Affiliation(s)
- Dan Wang
- State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, No. 29 Yudao Street, Nanjing 210016, China
| | - Milena Lippmann
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
| | | | - Anita Ehnes
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
| | - Dmitri Novikov
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
| | - Robert Meißner
- Hamburg University of Technology, 21073 Hamburg, Germany
- Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany
| | - Oliver H Seeck
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany.
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16
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Fidanyan K, Liu G, Rossi M. Ab initio study of water dissociation on a charged Pd(111) surface. J Chem Phys 2023; 158:094707. [PMID: 36889966 DOI: 10.1063/5.0139082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
The interactions between molecules and electrode surfaces play a key role in electrochemical processes and are a subject of extensive research, both experimental and theoretical. In this paper, we address the water dissociation reaction on a Pd(111) electrode surface, modeled as a slab embedded in an external electric field. We aim at unraveling the relationship between surface charge and zero-point energy in aiding or hindering this reaction. We calculate the energy barriers with dispersion-corrected density-functional theory and an efficient parallel implementation of the nudged-elastic-band method. We show that the lowest dissociation barrier and consequently the highest reaction rate take place when the field reaches a strength where two different geometries of the water molecule in the reactant state are equally stable. The zero-point energy contributions to this reaction, on the other hand, remain nearly constant across a wide range of electric field strengths, despite significant changes in the reactant state. Interestingly, we show that the application of electric fields that induce a negative charge on the surface can make nuclear tunneling more significant for these reactions.
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Affiliation(s)
- Karen Fidanyan
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Guoyuan Liu
- Department of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Mariana Rossi
- Department of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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17
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Pireddu G, Rotenberg B. Frequency-Dependent Impedance of Nanocapacitors from Electrode Charge Fluctuations as a Probe of Electrolyte Dynamics. PHYSICAL REVIEW LETTERS 2023; 130:098001. [PMID: 36930930 DOI: 10.1103/physrevlett.130.098001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
The frequency-dependent impedance is a fundamental property of electrical components. We show that it can be determined from the equilibrium dynamical fluctuations of the electrode charge in constant-potential molecular simulations, extending in particular a fluctuation-dissipation relation for the capacitance recovered in the low-frequency limit and provide an illustration on water-gold nanocapacitors. This Letter opens the way to the interpretation of electrochemical impedance measurements in terms of microscopic mechanisms, directly from the dynamics of the electrolyte, or indirectly via equivalent circuit models as in experiments.
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Affiliation(s)
- Giovanni Pireddu
- Sorbonne Université, CNRS, Physico-chimie des Électrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005 Paris, France
| | - Benjamin Rotenberg
- Sorbonne Université, CNRS, Physico-chimie des Électrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005 Paris, France
- Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, 80039 Amiens Cedex, France
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18
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Li XY, Jin XF, Yang XH, Wang X, Le JB, Cheng J. Molecular understanding of the Helmholtz capacitance difference between Cu(100) and graphene electrodes. J Chem Phys 2023; 158:084701. [PMID: 36859091 DOI: 10.1063/5.0139534] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Unraveling the origin of Helmholtz capacitance is of paramount importance for understanding the interfacial structure and electrostatic potential distribution of electric double layers (EDL). In this work, we combined the methods of ab initio molecular dynamics and classical molecular dynamics and modeled electrified Cu(100)/electrolyte and graphene/electrolyte interfaces for comparison. It was proposed that the Helmholtz capacitance is composed of three parts connected in series: the usual solvent capacitance, water chemisorption induced capacitance, and Pauling repulsion caused gap capacitance. We found the Helmholtz capacitance of graphene is significantly lower than that of Cu(100), which was attributed to two intrinsic factors. One is that graphene has a wider gap layer at interface, and the other is that graphene is less active for water chemisorption. Finally, based on our findings, we provide suggestions for how to increase the EDL capacitance of graphene-based materials in future work, and we also suggest that the new understanding of the potential distribution across the Helmholtz layer may help explain some experimental phenomena of electrocatalysis.
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Affiliation(s)
- Xiang-Ying Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiang-Feng Jin
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiao-Hui Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xue Wang
- Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Jia-Bo Le
- Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Jun Cheng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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19
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Dasgupta N, Ho TA, Rempe SB, Wang Y. Hydrophobic Nanoconfinement Enhances CO 2 Conversion to H 2CO 3. J Phys Chem Lett 2023; 14:1693-1701. [PMID: 36757174 DOI: 10.1021/acs.jpclett.3c00124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Understanding the formation of H2CO3 in water from CO2 is important in environmental and industrial processes. Although numerous investigations have studied this reaction, the conversion of CO2 to H2CO3 in nanopores, and how it differs from that in bulk water, has not been understood. We use ReaxFF metadynamics molecular simulations to demonstrate striking differences in the free energy of CO2 conversion to H2CO3 in bulk and nanoconfined aqueous environments. We find that nanoconfinement not only reduces the energy barrier but also reverses the reaction from endothermic in bulk water to exothermic in nanoconfined water. Also, charged intermediates are observed more often under nanoconfinement than in bulk water. Stronger solvation and more favorable proton transfer with increasing nanoconfinement enhance the thermodynamics and kinetics of the reaction. Our results provide a detailed mechanistic understanding of an important step in the carbonation process, which depends intricately on confinement, surface chemistry, and CO2 concentration.
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Affiliation(s)
- Nabankur Dasgupta
- Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Tuan A Ho
- Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Susan B Rempe
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Yifeng Wang
- Nuclear Waste Disposal Research and Analysis Department, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
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20
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Dinpajooh M, Matyushov DV. Interface Dielectric Constant of Water at the Surface of a Spherical Solute. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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21
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Deißenbeck F, Wippermann S. Dielectric Properties of Nanoconfined Water from Ab Initio Thermopotentiostat Molecular Dynamics. J Chem Theory Comput 2023; 19:1035-1043. [PMID: 36705611 PMCID: PMC9933428 DOI: 10.1021/acs.jctc.2c00959] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We discuss how to include our recently proposed thermopotentiostat technique [Deissenbeck et al. Phys. Rev. Lett. 2021, 126, 136803] into any existing ab initio molecular dynamics (AIMD) package. Using thermopotentiostat AIMD simulations in the canonical NVTΦ ensemble at a constant electrode potential, we compute the polarization bound charge and dielectric response of interfacial water from first principles.
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Affiliation(s)
- Florian Deißenbeck
- Max-Planck-Institut
für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf, Germany
| | - Stefan Wippermann
- Max-Planck-Institut
für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf, Germany,Philipps-Universität
Marburg, Renthof 5, 35032 Marburg, Germany,E-mail:
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22
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Nanoconfinement facilitates reactions of carbon dioxide in supercritical water. Nat Commun 2022; 13:5932. [PMID: 36209274 PMCID: PMC9547913 DOI: 10.1038/s41467-022-33696-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 09/27/2022] [Indexed: 11/08/2022] Open
Abstract
The reactions of CO2 in water under extreme pressure-temperature conditions are of great importance to the carbon storage and transport below Earth’s surface, which substantially affect the carbon budget in the atmosphere. Previous studies focus on the CO2(aq) solutions in the bulk phase, but underground aqueous solutions are often confined to the nanoscale, and nanoconfinement and solid-liquid interfaces may substantially affect chemical speciation and reaction mechanisms, which are poorly known on the molecular scale. Here, we apply extensive ab initio molecular dynamics simulations to study aqueous carbon solutions nanoconfined by graphene and stishovite (SiO2) at 10 GPa and 1000 ~ 1400 K. We find that CO2(aq) reacts more in nanoconfinement than in bulk. The stishovite-water interface makes the solutions more acidic, which shifts the chemical equilibria, and the interface chemistry also significantly affects the reaction mechanisms. Our findings suggest that CO2(aq) in deep Earth is more active than previously thought, and confining CO2 and water in nanopores may enhance the efficiency of mineral carbonation. Aqueous CO2 under nanoconfinement is of great importance to the carbon storage and transport in Earth. Here, the authors apply ab initio molecular dynamics simulations to study the effects of confinement and interfaces, and show that that CO(aq) reacts more in nanoconfinement than in bulk.
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23
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Zhao W, Xu WW, Jiang J, Zhao X, Duan X, Sun Y, Francisco JS, Zeng XC. Evidence of Formation of Monolayer Hydrated Salts in Nanopores. J Am Chem Soc 2022; 144:18976-18985. [PMID: 36197785 DOI: 10.1021/jacs.2c07372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Despite much effort being devoted to the study of ionic aqueous solutions at the nanoscale, our fundamental understanding of the microscopic kinetic and thermodynamic behaviors in these systems remains largely incomplete. Herein, we reported the first 10 μs molecular dynamics simulation, providing evidence of the spontaneous formation of monolayer hexagonal honeycomb hydrated salts of XCl2·6H2O (X = Ba, Sr, Ca, and Mg) from electrolyte aqueous solutions confined in an angstrom-scale slit under ambient conditions. By using both the classical molecular dynamics simulations and the first-principles Born-Oppenheimer molecular dynamics simulations, we further demonstrated that the hydrated salts were stable not only at ambient temperature but also at elevated temperatures. This phenomenon of formation of hydrated salt in water is contrary to the conventional view. The free energy calculations and dehydration analyses indicated that the spontaneous formation of hydrated salts can be attributed to the interplay between ion hydration and Coulombic attractions in the highly confined water. In addition to providing molecular-level insights into the novel behavior of ionic aqueous solutions at the nanoscale, our findings may have implications for the future exploration of potential existence of water molecules in the saline deposits on hot planets.
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Affiliation(s)
- Wenhui Zhao
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Wen Wu Xu
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Jian Jiang
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States.,Department of Materials Science & Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China
| | - Xiaorong Zhao
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Xiangmei Duan
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Yunxiang Sun
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Joseph S Francisco
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Xiao Cheng Zeng
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States.,Department of Materials Science & Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China
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24
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Ahrens-Iwers LJ, Janssen M, Tee SR, Meißner RH. ELECTRODE: An electrochemistry package for atomistic simulations. J Chem Phys 2022; 157:084801. [DOI: 10.1063/5.0099239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Constant potential methods (CPM) enable computationally efficient simulations of the solid-liquid interface at conducting electrodes in molecular dynamics (MD). They have been successfully used, for example, to realistically model the behavior of ionic liquids or water-in-salt electrolytes in supercapacitors and batteries. The CPM models conductive electrodes by updating charges of individual electrode atoms according to the applied electric potential and the (time-dependent) local electrolyte structure. Here we present a feature-rich CPM implementation, called ELECTRODE, for the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), which includes a constrained charge method and a thermo-potentiostat. The ELECTRODE package also contains a finite-field approach, multiple corrections for non-periodic boundary conditions of the particle-particle particle-mesh solver, and a Thomas-Fermi model for using non-ideal metals as electrodes. We demonstrate the capabilities of this implementation for a parallel-plate electrical double-layer capacitor, for which we have investigated the charging times with the different implemented methods and found an interesting relationship between water and ionic dipole relaxations. To prove the validity of the one-dimensional correction for the long-range electrostatics, we estimated the vacuum capacitance of two co-axial carbon nanotubes and compared it to structureless cylinders, for which an analytical expression exists. In summary, the ELECTRODE package enables efficient electrochemical simulations using state-of-the-art methods, allowing one to simulate even heterogeneous electrodes. Moreover, it allows unveiling more rigorously how electrode curvature affects the capacitance with the one-dimensional correction.
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Affiliation(s)
| | | | - Shern Ren Tee
- The University of Queensland Australian Institute for Bioengineering and Nanotechnology, Australia
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25
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de Souza JP, Kornyshev AA, Bazant MZ. Polar liquids at charged interfaces: A dipolar shell theory. J Chem Phys 2022; 156:244705. [PMID: 35778078 DOI: 10.1063/5.0096439] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The structure of polar liquids and electrolytic solutions, such as water and aqueous electrolytes, at interfaces underlies numerous phenomena in physics, chemistry, biology, and engineering. In this work, we develop a continuum theory that captures the essential features of dielectric screening by polar liquids at charged interfaces, including decaying spatial oscillations in charge and mass, starting from the molecular properties of the solvent. The theory predicts an anisotropic dielectric tensor of interfacial polar liquids previously studied in molecular dynamics simulations. We explore the effect of the interfacial polar liquid properties on the capacitance of the electrode/electrolyte interface and on hydration forces between two plane-parallel polarized surfaces. In the linear response approximation, we obtain simple formulas for the characteristic decay lengths of molecular and ionic profiles at the interface.
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Affiliation(s)
- J Pedro de Souza
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Alexei A Kornyshev
- Department of Chemistry and Thomas Young Centre for Theory and Simulation of Materials, Imperial College London, Molecular Sciences Research Hub, White City Campus, London W12 0BZ, United Kingdom
| | - Martin Z Bazant
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
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26
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Zhao X, Liu Y, Lin D, Zhu W, Ma N, Xu WW, Zhao W, Sun Y, Zeng XC. Anomalous Phase Behaviors of Monolayer NaCl Aqueous Solutions Induced by Effective Coulombic Interactions within Angstrom-Scale Slits. J Phys Chem Lett 2022; 13:2704-2710. [PMID: 35302778 DOI: 10.1021/acs.jpclett.2c00501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Interests in subnanofluidic devices have called for molecular dynamics (MD) simulation studies of the thermodynamic behavior of monolayer salt solution within angstrom-scale slits. However, it still remains a grand challenge to accurately describe the Coulombic interactions by incorporating the effects of charge transfer and electronic dielectric screening. Herein, by using the electronic continuum model, where the effective ion charges are fine-tuned with a scaling factor of λ, we present simulation evidence that the effective Coulombic interactions among Na+/Cl- ions can strongly affect the behavior of monolayer ionic aqueous solution. Our microsecond-scale MD simulations show that only the counterions with moderate effective charges (0.3 ≤ λ ≤ 0.8) can dissolve in monolayer water, whereas the high effective charges (λ ≥ 0.85) induce ions to assemble into monolayer nanocrystals, and ions with the low effective charges (λ ≤ 0.2) exhibit gas-like nanobubble. These findings could provide deeper insights into the physical chemistry behind subnanofluidic iontronic devices.
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Affiliation(s)
- Xiaorong Zhao
- Department of Physics, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Yuying Liu
- Department of Physics, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Dongdong Lin
- Department of Physics, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Weiduo Zhu
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China
| | - Nan Ma
- Department of Physics, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Wen Wu Xu
- Department of Physics, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Wenhui Zhao
- Department of Physics, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Yunxiang Sun
- Department of Physics, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Xiao Cheng Zeng
- Department of Chemistry, University of Nebraska─Lincoln, Lincoln, Nebraska 68588, United States
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27
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Ringe S, Hörmann NG, Oberhofer H, Reuter K. Implicit Solvation Methods for Catalysis at Electrified Interfaces. Chem Rev 2021; 122:10777-10820. [PMID: 34928131 PMCID: PMC9227731 DOI: 10.1021/acs.chemrev.1c00675] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
![]()
Implicit solvation
is an effective, highly coarse-grained approach
in atomic-scale simulations to account for a surrounding liquid electrolyte
on the level of a continuous polarizable medium. Originating in molecular
chemistry with finite solutes, implicit solvation techniques are now
increasingly used in the context of first-principles modeling of electrochemistry
and electrocatalysis at extended (often metallic) electrodes. The
prevalent ansatz to model the latter electrodes and the reactive surface
chemistry at them through slabs in periodic boundary condition supercells
brings its specific challenges. Foremost this concerns the difficulty
of describing the entire double layer forming at the electrified solid–liquid
interface (SLI) within supercell sizes tractable by commonly employed
density functional theory (DFT). We review liquid solvation methodology
from this specific application angle, highlighting in particular its
use in the widespread ab initio thermodynamics approach
to surface catalysis. Notably, implicit solvation can be employed
to mimic a polarization of the electrode’s electronic density
under the applied potential and the concomitant capacitive charging
of the entire double layer beyond the limitations of the employed
DFT supercell. Most critical for continuing advances of this effective
methodology for the SLI context is the lack of pertinent (experimental
or high-level theoretical) reference data needed for parametrization.
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Affiliation(s)
- Stefan Ringe
- Department of Energy Science and Engineering, Daegu Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea.,Energy Science & Engineering Research Center, Daegu Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Nicolas G Hörmann
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.,Chair for Theoretical Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstraße 4, D-85747 Garching, Germany
| | - Harald Oberhofer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstraße 4, D-85747 Garching, Germany.,Chair for Theoretical Physics VII and Bavarian Center for Battery Technology (BayBatt), University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Karsten Reuter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
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28
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Microscopic origin of the effect of substrate metallicity on interfacial free energies. Proc Natl Acad Sci U S A 2021; 118:2108769118. [PMID: 34876519 DOI: 10.1073/pnas.2108769118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2021] [Indexed: 11/18/2022] Open
Abstract
We investigate the effect of the metallic character of solid substrates on solid-liquid interfacial thermodynamics using molecular simulations. Building on the recent development of a semiclassical Thomas-Fermi model to tune the metallicity in classical molecular dynamics simulations, we introduce a thermodynamic integration framework to compute the evolution of the interfacial free energy as a function of the Thomas-Fermi screening length. We validate this approach against analytical results for empty capacitors and by comparing the predictions in the presence of an electrolyte with values determined from the contact angle of droplets on the surface. The general expression derived in this work highlights the role of the charge distribution within the metal. We further propose a simple model to interpret the evolution of the interfacial free energy with voltage and Thomas-Fermi length, which allows us to identify the charge correlations within the metal as the microscopic origin of the evolution of the interfacial free energy with the metallic character of the substrate. This methodology opens the door to the molecular-scale study of the effect of the metallic character of the substrate on confinement-induced transitions in ionic systems, as reported in recent atomic force microscopy and surface force apparatus experiments.
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29
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Pireddu G, Scalfi L, Rotenberg B. A molecular perspective on induced charges on a metallic surface. J Chem Phys 2021; 155:204705. [PMID: 34852473 DOI: 10.1063/5.0076127] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Understanding the response of the surface of metallic solids to external electric field sources is crucial to characterize electrode-electrolyte interfaces. Continuum electrostatics offer a simple description of the induced charge density at the electrode surface. However, such a simple description does not take into account features related to the atomic structure of the solid and to the molecular nature of the solvent and of the dissolved ions. In order to illustrate such effects and assess the ability of continuum electrostatics to describe the induced charge distribution, we investigate the behavior of a gold electrode interacting with sodium or chloride ions fixed at various positions, in a vacuum or in water, using all-atom constant-potential classical molecular dynamics simulations. Our analysis highlights important similarities between the two approaches, especially under vacuum conditions and when the ion is sufficiently far from the surface, as well as some limitations of the continuum description, namely, neglecting the charges induced by the adsorbed solvent molecules and the screening effect of the solvent when the ion is close to the surface. While the detailed features of the charge distribution are system-specific, we expect some of our generic conclusions on the induced charge density to hold for other ions, solvents, and electrode surfaces. Beyond this particular case, the present study also illustrates the relevance of such molecular simulations to serve as a reference for the design of improved implicit solvent models of electrode-electrolyte interfaces.
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Affiliation(s)
- Giovanni Pireddu
- Sorbonne Université, CNRS, Physico-chimie des Électrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005 Paris, France
| | - Laura Scalfi
- Sorbonne Université, CNRS, Physico-chimie des Électrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005 Paris, France
| | - Benjamin Rotenberg
- Sorbonne Université, CNRS, Physico-chimie des Électrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005 Paris, France
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Le JB, Yang XH, Zhuang YB, Jia M, Cheng J. Recent Progress toward Ab Initio Modeling of Electrocatalysis. J Phys Chem Lett 2021; 12:8924-8931. [PMID: 34499508 DOI: 10.1021/acs.jpclett.1c02086] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Electrode potential is the key factor for controlling electrocatalytic reactions at electrochemical interfaces, and moreover, it is also known that the pH and solutes (e.g., cations) of the solution have prominent effects on electrocatalysis. Understanding these effects requires microscopic information on the electrochemical interfaces, in which theoretical simulations can play an important role. This Perspective summarizes the recent progress in method development for modeling electrochemical interfaces, including different methods for describing the electrolytes at the interfaces and different schemes for charging up the electrode surfaces. In the final section, we provide an outlook for future development in modeling methods and their applications to electrocatalysis.
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Affiliation(s)
- Jia-Bo Le
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiao-Hui Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yong-Bin Zhuang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Mei Jia
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jun Cheng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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Abstract
Molecular dynamics simulations in a constant potential ensemble are an increasingly important tool to investigate charging mechanisms in next-generation energy storage devices. We present a highly efficient approach to compute electrostatic interactions in simulations employing a constant potential method (CPM) by introducing a particle-particle particle-mesh solver specifically designed for treating long-range interactions in a CPM. Moreover, we present evidence that a dipole correction term-commonly used in simulations with a slab-like geometry-must be used with caution if it is also to be used within a CPM. It is demonstrated that artifacts arising from the usage of the dipole correction term can be circumvented by enforcing a charge neutrality condition in the evaluation of the electrode charges at a given external potential.
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Affiliation(s)
| | - Robert H Meißner
- Institute of Polymers and Composites, Hamburg University of Technology, Hamburg, Germany
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Abstract
It has long been anticipated that dielectric constants of polar liquids are reduced in the interfacial layer. Recent experiments and computer simulations support these expectations. A strong reduction of the dielectric constant is found in the direction perpendicular to a planar substrate, while the parallel response is bulk-like. This Perspective highlights recent theoretical calculations and simulations with an eye on relating them to properties observable in the laboratory. The average interface dielectric constant computed from simulations connects to thin films experiments, but this cannot be extended to screening of charges. In contrast to dielectric theories where a single dielectric constant gauges both the polarization energy and screening, these two signatures of dielectric polarization diverge on the molecular scale. The reduction of the dielectric constant of water in thin films is currently viewed as a combined effect of geometric confinement imposed by the substrate and the reconstruction of water hydrogen bonds in the surface layer.
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Affiliation(s)
- Dmitry V Matyushov
- School of Molecular Sciences and Department of Physics, Arizona State University, PO Box 871504, Tempe, Arizona 85287-1504, United States
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Muñoz-Santiburcio D, Marx D. Confinement-Controlled Aqueous Chemistry within Nanometric Slit Pores. Chem Rev 2021; 121:6293-6320. [PMID: 34006106 DOI: 10.1021/acs.chemrev.0c01292] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In this Focus Review, we put the spotlight on very recent insights into the fascinating world of wet chemistry in the realm offered by nanoconfinement of water in mechanically rather rigid and chemically inert planar slit pores wherein only monolayer and bilayer water lamellae can be hosted. We review the effect of confinement on different aspects such as hydrogen bonding, ion diffusion, and charge defect migration of H+(aq) and OH-(aq) in nanoconfined water depending on slit pore width. A particular focus is put on the strongly modulated local dielectric properties as quantified in terms of anisotropic polarization fluctuations across such extremely confined water films and their putative effects on chemical reactions therein. The stunning findings disclosed only recently extend wet chemistry in particular and solvation science in general toward extreme molecular confinement conditions.
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Affiliation(s)
- Daniel Muñoz-Santiburcio
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany.,CIC nanoGUNE BRTA, Tolosa Hiribidea 76, 20018 San Sebastián, Spain
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
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Olivieri JF, Hynes JT, Laage D. Confined Water's Dielectric Constant Reduction Is Due to the Surrounding Low Dielectric Media and Not to Interfacial Molecular Ordering. J Phys Chem Lett 2021; 12:4319-4326. [PMID: 33914550 DOI: 10.1021/acs.jpclett.1c00447] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Liquid water confined within nanometer-sized channels exhibits a surprisingly low dielectric constant along the direction orthogonal to the channel walls. This is typically assumed to result from a pronounced heterogeneity across the sample: the dielectric constant would be bulk-like everywhere except at the interface, where it would be dramatically reduced by strong restrictions on interfacial molecules. Here we study the dielectric properties of water confined within graphene slit channels via classical molecular dynamics simulations. We show that the permittivity reduction is not due to any important alignment of interfacial water molecules, but instead to the long-ranged anisotropic dipole correlations combined with an excluded-volume effect of the low-dielectric confining material. The bulk permittivity is gradually recovered only over several nanometers due to the impact of long-range electrostatics, rather than structural features. This has important consequences for the control of, e.g., ion transport and chemical reactivity in nanoscopic channels and droplets.
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Affiliation(s)
- Jean-François Olivieri
- PASTEUR, Department of Chemistry, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - James T Hynes
- PASTEUR, Department of Chemistry, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Damien Laage
- PASTEUR, Department of Chemistry, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
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