1
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Creazzo F, Luber S. Water-air interface revisited by means of path-integral ab initio molecular dynamics. Phys Chem Chem Phys 2024; 26:21290-21302. [PMID: 39078670 PMCID: PMC11305098 DOI: 10.1039/d4cp02500h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2024] [Accepted: 07/21/2024] [Indexed: 07/31/2024]
Abstract
Although nuclear quantum effects (NQEs) have been considered on bulk liquid water, the impact of these latter on the air-water interface has not yet been reported. Herein, by performing and comparing ab initio molecular dynamics (AIMD) and path integral AIMD (PI-AIMD) simulations, we reveal the impact of NQEs on structural, dynamical and electronic properties as well as IR spectra of the air-water interface at room temperature. NQEs, being able to describe a more accurate proton delocalization in H-bonded system than AIMD, reveal a different structural arrangement and dynamical behaviour of both bulk and interfacial water molecules in comparison to AIMD results. A more de-structured and de-bound water arrangement and coordination are identified when the quantum nature of nuclei are considered for both bulk and interfacial water molecules. Structural properties, such as inter-/intra-molecular bond lengths, coordination numbers and H-bonding angles of bulk and interfacial water molecules here calculated, are affected by NQEs mitigating the overstructured description given by AIMD. Further evidences of an AIMD overstructured description of bulk water are in the computed IR spectra, where an increased absorption peak intensity and an increased strength of the hydrogen-bond network are alleviated by NQEs. In addition, NQEs show a valuable impact on the electronic structure of the air-water interface, reducing the total valence bandwidth and the electronic energy band-gap when passing from bulk to interfacial water. This work proves how NQEs significantly affect properties and features of the air-water interface, that are essential to accurately describe H-bonded interfacial systems.
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Affiliation(s)
- Fabrizio Creazzo
- Department of Chemistry, University of Zurich, Zurich, Switzerland.
| | - Sandra Luber
- Department of Chemistry, University of Zurich, Zurich, Switzerland.
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2
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Donkor ED, Offei-Danso A, Rodriguez A, Sciortino F, Hassanali A. Beyond Local Structures in Critical Supercooled Water through Unsupervised Learning. J Phys Chem Lett 2024; 15:3996-4005. [PMID: 38574274 DOI: 10.1021/acs.jpclett.4c00383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
The presence of a second critical point in water has been a topic of intense investigation for the last few decades. The molecular origins underlying this phenomenon are typically rationalized in terms of the competition between local high-density (HD) and low-density (LD) structures. Their identification often requires designing parameters that are subject to human intervention. Herein, we use unsupervised learning to discover structures in atomistic simulations of water close to the liquid-liquid critical point (LLCP). Encoding the information on the environment using local descriptors, we do not find evidence for two distinct thermodynamic structures. In contrast, when we deploy nonlocal descriptors that probe instead heterogeneities on the nanometer length scale, this leads to the emergence of LD and HD domains rationalizing the microscopic origins of the density fluctuations close to criticality.
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Affiliation(s)
- Edward Danquah Donkor
- The Abdus Salam International Center for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, 34136 Trieste, Italy
| | - Adu Offei-Danso
- The Abdus Salam International Center for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, 34136 Trieste, Italy
| | - Alex Rodriguez
- The Abdus Salam International Center for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy
- Dipartimento di Matematica, Informatica e Geoscienze, Università degli studi di Trieste, via Valerio 12/1, 34127 Trieste, Italy
| | - Francesco Sciortino
- Dipartimento di Fisica, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Rome, Italy
| | - Ali Hassanali
- The Abdus Salam International Center for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy
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3
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Ajide MT, English NJ. Nonequilibrium Ab Initio Molecular Dynamics Simulation of Water Splitting at Fe 2O 3-Hematite/Water Interfaces in an External Electric Field. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:24088-24105. [PMID: 38148852 PMCID: PMC10749450 DOI: 10.1021/acs.jpcc.3c05119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 11/17/2023] [Accepted: 11/17/2023] [Indexed: 12/28/2023]
Abstract
In the exploration of the optimal material for achieving the photoelectrochemical dissociation of water into hydrogen, hematite (α-Fe2O3) emerges as a highly promising candidate for proof-of-concept demonstrations. Recent studies suggest that the concurrent application of external electric fields could enhance the photoelectrochemical (PEC) process. To delve into this, we conducted nonequilibrium ab initio molecular dynamics (NE-AIMD) simulations in this study, focusing on hematite-water interfaces at room temperature under progressively stronger electric fields. Our findings reveal intriguing evidence of water molecule adsorption and dissociation, as evidenced by an analysis of the structural properties of the hydrated layered surface of the hematite-water interface. Additionally, we scrutinized intermolecular structures using radial distribution functions (RDFs) to explore the interaction between the hematite slab and water. Notably, the presence of a Grotthuss hopping mechanism became apparent as the electric field strength increased. A comprehensive discussion based on intramolecular geometry highlighted aspects such as hydrogen-bond lengths, H-bond angles, average H-bond numbers, and the observed correlation existing among the hydrogen-bond strength, bond-dissociation energy, and H-bond lifetime. Furthermore, we assessed the impact of electric fields on the librational, bending, and stretching modes of hydrogen atoms in water by calculating the vibrational density of states (VDOS). This analysis revealed distinct field effects for the three characteristic band modes, both in the bulk region and at the hematite-water interface. We also evaluated the charge density of active elements at the aqueous hematite surface, delving into field-induced electronic charge-density variations through the Hirshfeld charge density analysis of atomic elements. Throughout this work, we drew clear distinctions between parallel and antiparallel field alignments at the hematite-water interface, aiming to elucidate crucial differences in local behavior for each surface direction of the hematite-water interface.
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Affiliation(s)
- Mary T. Ajide
- School of Chemical &
Bioprocess Engineering, University College
Dublin, Belfield, Dublin 4, Ireland
| | - Niall J. English
- School of Chemical &
Bioprocess Engineering, University College
Dublin, Belfield, Dublin 4, Ireland
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4
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Rashid MAM, Rahman M, Acter T, Uddin N. Identifying the acidic or basic behavior of surface water: a QM/MM-MD study. Phys Chem Chem Phys 2023; 25:31194-31205. [PMID: 37955174 DOI: 10.1039/d3cp02080k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
Controversies on the water surface were theoretically addressed with the help of large scale quantum mechanical molecular dynamics (QMMD) simulations on water surface model systems with and without excess hydroniums and hydroxides. It was revealed that the thermodynamic surface structures of these ions strongly depend on their location and dipole orientation. Fast hydronium diffusion by proton transfer establishes a wider kinetic depth distribution (∼6 Å) than that predicted by its thermodynamic affinity for the water surface, while slow hydroxide is shallowly trapped below the outermost molecular layer (3-4 Å). In addition, the anisotropic orientation of surface water dipole can generate a substantial magnitude of surface potential, which extends to a depth of a few molecular layers. With these distinctively different surface properties of two ions and water molecules, the seemingly contradictory observations of acidic and negatively charged water surfaces may be successfully explained. That is, the negative surface charge of neutral water mostly stems from intrinsic water properties such as water dipole orientation and electron density spillage at the surface, rather than surface OH- ions. The enhanced acidity of the water surface can be attributed in large part to the kinetic depth profile of ion density in addition to static thermodynamic origin. Furthermore, the different depth profiles of the two ions may differently affect the surface-sensitive spectroscopic observations.
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Affiliation(s)
- Md Al Mamunur Rashid
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, 02792, South Korea
| | - Mofizur Rahman
- Research and Development Center, Berger Paints Bangladesh Limited, Berger House, Dhaka-1230, Bangladesh
| | - Thamina Acter
- Department of Mathematical and Physical Sciences, East West University, Aftabnagar, Dhaka-1212, Bangladesh
| | - Nizam Uddin
- Department of Nutrition and Food Engineering, Daffodil International University, Birulia, Dhaka-1216, Bangladesh.
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Di Pino S, Donkor ED, Sánchez VM, Rodriguez A, Cassone G, Scherlis D, Hassanali A. ZundEig: The Structure of the Proton in Liquid Water from Unsupervised Learning. J Phys Chem B 2023; 127:9822-9832. [PMID: 37930954 DOI: 10.1021/acs.jpcb.3c06078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
The structure of the excess proton in liquid water has been the subject of lively debate on both experimental and theoretical fronts for the last century. Fluctuations of the proton are typically interpreted in terms of limiting states referred to as the Eigen and Zundel species. Here, we put these ideas under the microscope, taking advantage of recent advances in unsupervised learning that use local atomic descriptors to characterize environments of acidic water combined with advanced clustering techniques. Our agnostic approach leads to the observation of only one charged cluster and two neutral ones. We demonstrate that the charged cluster involving the excess proton is best seen as an ionic topological defect in water's hydrogen bond network, forming a single local minimum on the global free-energy landscape. This charged defect is a highly fluxional moiety, where the idealized Eigen and Zundel species are neither limiting configurations nor distinct thermodynamic states. Instead, the ionic defect enhances the presence of neutral water defects through strong interactions with the network. We dub the combination of the charged and neutral defect clusters as ZundEig, demonstrating that the fluctuations between these local environments provide a general framework for rationalizing more descriptive notions of the proton in the existing literature.
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Affiliation(s)
- Solana Di Pino
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | - Edward Danquah Donkor
- International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
| | - Veronica M Sánchez
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | - Alex Rodriguez
- International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
- Dipartimento di Matematica e Geoscienze, Universitá degli Studi di Trieste, via Alfonso Valerio 12/1, 34127 Trieste, Italy
| | - Giuseppe Cassone
- Institute for Chemical-Physical Processes, National Research Council (CNR-IPCF), Viale Stagno d'Alcontres 37, 98158 Messina, Italy
| | - Damian Scherlis
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | - Ali Hassanali
- International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
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Martins-Costa MTC, Ruiz-López MF. Probing solvation electrostatics at the air–water interface. Theor Chem Acc 2023. [DOI: 10.1007/s00214-023-02969-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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7
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Creazzo F, Luber S. Water-Assisted Chemical Route Towards the Oxygen Evolution Reaction at the Hydrated (110) Ruthenium Oxide Surface: Heterogeneous Catalysis via DFT-MD and Metadynamics Simulations. Chemistry 2021; 27:17024-17037. [PMID: 34486184 PMCID: PMC9293344 DOI: 10.1002/chem.202102356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Indexed: 11/15/2022]
Abstract
Notwithstanding that RuO2 is a promising catalyst for the oxygen evolution reaction (OER), a plethora of fundamental details on its catalytic properties are still elusive, severely limiting its large‐scale deployment. It is also established experimentally that corrosion and wettability of metal oxides can, in fact, enhance the catalytic activity for OER owing to the formation of a hydrated surface layer. However, the mechanistic interplay between surface wettability, interfacial water dynamics and OER across RuO2, and what degree these processes are correlated are still debated. Herein, spin‐polarized Density Functional Theory Molecular Dynamics (DFT‐MD) simulations, coupled with advanced enhanced sampling methods in the well‐tempered metadynamics framework, are applied to gain a global understanding of RuO2 aqueous interface (explicit water solvent) in catalyzing the OER, and hence possibly help in the design of novel catalysts in the context of photochemical water oxidation. The present study quantitatively assesses the free‐energy barriers behind the OER at the (110)‐RuO2 catalyst surface revealing plausible pathways composing the reaction network of the O2 evolution. In particular, OER is investigated at room temperature when such a surface is exposed to both gas‐phase and liquid‐phase water. Albeit a unique efficient pathway has been identified in the gas‐phase OER, a surprisingly lowest‐free‐energy‐requiring reaction route is possible when (110)‐RuO2 is in contact with explicit liquid water. By estimating the free‐energy surfaces associated to these processes, we reveal a noticeable water‐assisted OER mechanism which involves a crucial proton‐transfer‐step assisted by the local water environment. These findings pave the way toward the systematic usage of DFT‐MD coupled with metadynamics techniques for the fine assessment of the activity of catalysts, considering finite‐temperature and explicit‐solvent effects.
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Affiliation(s)
- Fabrizio Creazzo
- Department of Chemistry, University of Zurich, Zurich, Switzerland
| | - Sandra Luber
- Department of Chemistry, University of Zurich, Zurich, Switzerland
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Pezzotti S, Serva A, Sebastiani F, Brigiano FS, Galimberti DR, Potier L, Alfarano S, Schwaab G, Havenith M, Gaigeot MP. Molecular Fingerprints of Hydrophobicity at Aqueous Interfaces from Theory and Vibrational Spectroscopies. J Phys Chem Lett 2021; 12:3827-3836. [PMID: 33852317 PMCID: PMC9004482 DOI: 10.1021/acs.jpclett.1c00257] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/09/2021] [Indexed: 05/28/2023]
Abstract
Hydrophobicity/hydrophilicity of aqueous interfaces at the molecular level results from a subtle balance in the water-water and water-surface interactions. This is characterized here via density functional theory-molecular dynamics (DFT-MD) coupled with vibrational sum frequency generation (SFG) and THz-IR absorption spectroscopies. We show that water at the interface with a series of weakly interacting materials is organized into a two-dimensional hydrogen-bonded network (2D-HB-network), which is also found above some macroscopically hydrophilic silica and alumina surfaces. These results are rationalized through a descriptor that measures the number of "vertical" and "horizontal" hydrogen bonds formed by interfacial water, quantifying the competition between water-surface and water-water interactions. The 2D-HB-network is directly revealed by THz-IR absorption spectroscopy, while the competition of water-water and water-surface interactions is quantified from SFG markers. The combination of SFG and THz-IR spectroscopies is thus found to be a compelling tool to characterize the finest details of molecular hydrophobicity at aqueous interfaces.
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Affiliation(s)
- Simone Pezzotti
- Université
Paris-Saclay, Univ Evry, CNRS, LAMBE
UMR8587, 91025 Evry-Courcouronnes, France
| | - Alessandra Serva
- Université
Paris-Saclay, Univ Evry, CNRS, LAMBE
UMR8587, 91025 Evry-Courcouronnes, France
| | - Federico Sebastiani
- Department
of Physical Chemistry II, Ruhr University
Bochum, D-44801 Bochum, Germany
| | - Flavio Siro Brigiano
- Université
Paris-Saclay, Univ Evry, CNRS, LAMBE
UMR8587, 91025 Evry-Courcouronnes, France
| | - Daria Ruth Galimberti
- Université
Paris-Saclay, Univ Evry, CNRS, LAMBE
UMR8587, 91025 Evry-Courcouronnes, France
| | - Louis Potier
- Université
Paris-Saclay, Univ Evry, CNRS, LAMBE
UMR8587, 91025 Evry-Courcouronnes, France
| | - Serena Alfarano
- Department
of Physical Chemistry II, Ruhr University
Bochum, D-44801 Bochum, Germany
| | - Gerhard Schwaab
- Department
of Physical Chemistry II, Ruhr University
Bochum, D-44801 Bochum, Germany
| | - Martina Havenith
- Department
of Physical Chemistry II, Ruhr University
Bochum, D-44801 Bochum, Germany
| | - Marie-Pierre Gaigeot
- Université
Paris-Saclay, Univ Evry, CNRS, LAMBE
UMR8587, 91025 Evry-Courcouronnes, France
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9
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Influence of external static and alternating electric fields on self-diffusion of water from molecular dynamics. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114788] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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10
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Lentz J, Garofalini SH. Formation and migration of H3O+ and OH− ions at the water/silica and water/vapor interfaces under the influence of a static electric field: a molecular dynamics study. Phys Chem Chem Phys 2020; 22:22537-22548. [DOI: 10.1039/d0cp03656k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Water ‘layers’ 1 and 2 in pink; ‘layer’ 3 in blue and green over portion of glass surface (grey). +90° field causes water migration and clustering.
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Affiliation(s)
- Jesse Lentz
- Interfacial Molecular Science Laboratory
- Department of Materials Science and Engineering, Rutgers University
- USA
| | - Stephen H. Garofalini
- Interfacial Molecular Science Laboratory
- Department of Materials Science and Engineering, Rutgers University
- USA
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