1
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Mochizuki K, Adachi Y, Koga K. Close-Packed Ices in Nanopores. ACS NANO 2024; 18:347-354. [PMID: 38109520 PMCID: PMC10786155 DOI: 10.1021/acsnano.3c07084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 12/05/2023] [Accepted: 12/12/2023] [Indexed: 12/20/2023]
Abstract
Water molecules in any of the ice polymorphs organize themselves into a perfect four-coordinated hydrogen-bond network at the expense of dense packing. Even at high pressures, there seems to be no way to reconcile the ice rules with the close packing. Here, we report several close-packed ice phases in carbon nanotubes obtained from molecular dynamics simulations of two different water models. Typically they are in plastic states at high temperatures and are transformed into the hydrogen-ordered ice, keeping their close-packed structures at lower temperatures. The close-packed structures of water molecules in carbon nanotubes are identified with those of spheres in a cylinder. We present design principles of hydrogen-ordered, close-packed structures of ice in nanotubes, which suggest many possible dense ice forms with or without nonzero polarization. In fact, some of the simulated ices are found to exhibit ferroelectric ordering upon cooling.
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Affiliation(s)
- Kenji Mochizuki
- Department
of Chemistry, Zhejiang University, Hangzhou 310028, People’s Republic of China
| | - Yuji Adachi
- Graduate
School of Natural Sciences, Okayama University, Okayama 700-8530, Japan
- MEC
Company Ltd., Hyogo 660-0822, Japan
| | - Kenichiro Koga
- Department
of Chemistry, Okayama University, Okayama 700-8530, Japan
- Research Institute
for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
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2
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Lin B, Jiang J, Zeng XC, Li L. Temperature-pressure phase diagram of confined monolayer water/ice at first-principles accuracy with a machine-learning force field. Nat Commun 2023; 14:4110. [PMID: 37433823 DOI: 10.1038/s41467-023-39829-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 06/23/2023] [Indexed: 07/13/2023] Open
Abstract
Understanding the phase behaviour of nanoconfined water films is of fundamental importance in broad fields of science and engineering. However, the phase behaviour of the thinnest water film - monolayer water - is still incompletely known. Here, we developed a machine-learning force field (MLFF) at first-principles accuracy to determine the phase diagram of monolayer water/ice in nanoconfinement with hydrophobic walls. We observed the spontaneous formation of two previously unreported high-density ices, namely, zigzag quasi-bilayer ice (ZZ-qBI) and branched-zigzag quasi-bilayer ice (bZZ-qBI). Unlike conventional bilayer ices, few inter-layer hydrogen bonds were observed in both quasi-bilayer ices. Notably, the bZZ-qBI entails a unique hydrogen-bonding network that consists of two distinctive types of hydrogen bonds. Moreover, we identified, for the first time, the stable region for the lowest-density [Formula: see text] monolayer ice (LD-48MI) at negative pressures (<-0.3 GPa). Overall, the MLFF enables large-scale first-principle-level molecular dynamics (MD) simulations of the spontaneous transition from the liquid water to a plethora of monolayer ices, including hexagonal, pentagonal, square, zigzag (ZZMI), and hexatic monolayer ices. These findings will enrich our understanding of the phase behaviour of the nanoconfined water/ices and provide a guide for future experimental realization of the 2D ices.
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Affiliation(s)
- Bo Lin
- Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Jian Jiang
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, 999077, Hong Kong
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Xiao Cheng Zeng
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, 999077, Hong Kong.
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
| | - Lei Li
- Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.
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3
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Zeng Z, Wang T, Chen R, Suo M, Sun K, Theodorakis PE, Che Z. Two-dimensional partitioned square ice confined in graphene/graphite nanocapillaries. J Chem Phys 2022; 156:154510. [PMID: 35459309 DOI: 10.1063/5.0087690] [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
As one of the most fascinating confined water/ice phenomena, two-dimensional square ice has been extensively studied and experimentally confirmed in recent years. Apart from the unidirectional homogeneous square icing patterns considered in previous studies, the multidirectional partitioned square icing patterns are discovered in this study and characterized by molecular dynamics (MD) simulations. Square icing parameters are proposed to quantitatively distinguish the partitioned patterns from the homogeneous patterns and the liquid water. The number of graphene monolayers n is varied in this study, and the results show that it is more energetically favorable to form partitioned square icing patterns when the water molecules are confined between graphite sheets (n ≥ 2) compared to graphene (n = 1). This phenomenon is insensitive to n as long as n ≥ 2 because of the short-range nature of the interaction between water molecules and the carbon substrate. Moreover, it is energetically unfavorable to form partitioned square icing patterns for a single layer of water molecules even for n ≥ 2, verifying that the interaction between layers of water molecules is another dominant factor in the formation of partitioned structures. The conversion from partitioned structure to homogeneous square patterns is investigated by changing the pressure and the temperature. Based on the comprehensive MD simulations, this study unveils the formation mechanism of the partitioned square icing patterns.
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Affiliation(s)
- Zhen Zeng
- State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
| | - Tianyou Wang
- State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
| | - Rui Chen
- Department of Aeronautical and Automotive Engineering, Loughborough University, Loughborough LE11 3TU, United Kingdom
| | - Mengshan Suo
- State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
| | - Kai Sun
- State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
| | | | - Zhizhao Che
- State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
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4
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Abstract
Structures and processes at water/metal interfaces play an important technological role in electrochemical energy conversion and storage, photoconversion, sensors, and corrosion, just to name a few. However, they are also of fundamental significance as a model system for the study of solid-liquid interfaces, which requires combining concepts from the chemistry and physics of crystalline materials and liquids. Particularly interesting is the fact that the water-water and water-metal interactions are of similar strength so that the structures at water/metal interfaces result from a competition between these comparable interactions. Because water is a polar molecule and water and metal surfaces are both polarizable, explicit consideration of the electronic degrees of freedom at water/metal interfaces is mandatory. In principle, ab initio molecular dynamics simulations are thus the method of choice to model water/metal interfaces, but they are computationally still rather demanding. Here, ab initio simulations of water/metal interfaces will be reviewed, starting from static systems such as the adsorption of single water molecules, water clusters, and icelike layers, followed by the properties of liquid water layers at metal surfaces. Technical issues such as the appropriate first-principles description of the water-water and water-metal interactions will be discussed, and electrochemical aspects will be addressed. Finally, more approximate but numerically less demanding approaches to treat water at metal surfaces from first-principles will be briefly discussed.
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Affiliation(s)
- Axel Groß
- Institute of Theoretical Chemistry, Ulm University, 89069 Ulm, Germany.,Electrochemical Energy Storage, Helmholtz Institute Ulm (HIU), 89069 Ulm, Germany
| | - Sung Sakong
- Institute of Theoretical Chemistry, Ulm University, 89069 Ulm, Germany
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5
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Leoni F, Calero C, Franzese G. Nanoconfined Fluids: Uniqueness of Water Compared to Other Liquids. ACS NANO 2021; 15:19864-19876. [PMID: 34807577 PMCID: PMC8717635 DOI: 10.1021/acsnano.1c07381] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 11/18/2021] [Indexed: 05/27/2023]
Abstract
Nanoconfinement can drastically change the behavior of liquids, puzzling us with counterintuitive properties. It is relevant in applications, including decontamination and crystallization control. However, it still lacks a systematic analysis for fluids with different bulk properties. Here we address this gap. We compare, by molecular dynamics simulations, three different liquids in a graphene slit pore: (1) A simple fluid, such as argon, described by a Lennard-Jones potential; (2) an anomalous fluid, such as a liquid metal, modeled with an isotropic core-softened potential; and (3) water, the prototypical anomalous liquid, with directional HBs. We study how the slit-pore width affects the structure, thermodynamics, and dynamics of the fluids. All the fluids show similar oscillating properties by changing the pore size. However, their free-energy minima are quite different in nature: (i) are energy-driven for the simple liquid; (ii) are entropy-driven for the isotropic core-softened potential; and (iii) have a changing nature for water. Indeed, for water, the monolayer minimum is entropy driven, at variance with the simple liquid, while the bilayer minimum is energy driven, at variance with the other anomalous liquid. Also, water has a large increase in diffusion for subnm slit pores, becoming faster than bulk. Instead, the other two fluids have diffusion oscillations much smaller than water, slowing down for decreasing slit-pore width. Our results, clarifying that water confined at the subnm scale behaves differently from other (simple or anomalous) fluids under similar confinement, are possibly relevant in nanopores applications, for example, in water purification from contaminants.
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Affiliation(s)
- Fabio Leoni
- Department
of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Carles Calero
- Secció
de Física Estadística i Interdisciplinària-Departament
de Física de la Matèria Condensada, Institut de Nanociència i Nanotecnologia (IN2UB), Universitat
de Barcelona, Carrer Martí i Franquès 1, 08028 Barcelona, Spain
| | - Giancarlo Franzese
- Secció
de Física Estadística i Interdisciplinària-Departament
de Física de la Matèria Condensada, Institut de Nanociència i Nanotecnologia (IN2UB), Universitat
de Barcelona, Carrer Martí i Franquès 1, 08028 Barcelona, Spain
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6
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Dávila López AC, Eggert T, Reuter K, Hörmann NG. Static and dynamic water structures at interfaces: A case study with focus on Pt(111). J Chem Phys 2021; 155:194702. [PMID: 34800953 DOI: 10.1063/5.0067106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An accurate atomistic treatment of aqueous solid-liquid interfaces necessitates the explicit description of interfacial water ideally via ab initio molecular dynamics simulations. Many applications, however, still rely on static interfacial water models, e.g., for the computation of (electro)chemical reaction barriers and focus on a single, prototypical structure. In this work, we systematically study the relation between density functional theory-derived static and dynamic interfacial water models with specific focus on the water-Pt(111) interface. We first introduce a general construction protocol for static 2D water layers on any substrate, which we apply to the low index surfaces of Pt. Subsequently, we compare these with structures from a broad selection of reference works based on the Smooth Overlap of Atomic Positions descriptor. The analysis reveals some structural overlap between static and dynamic water ensembles; however, static structures tend to overemphasize the in-plane hydrogen bonding network. This feature is especially pronounced for the widely used low-temperature hexagonal ice-like structure. In addition, a complex relation between structure, work function, and adsorption energy is observed, which suggests that the concentration on single, static water models might introduce systematic biases that are likely reduced by averaging over consistently created structural ensembles, as introduced here.
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Affiliation(s)
| | - Thorben Eggert
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - 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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7
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Jiang J, Gao Y, Zhu W, Liu Y, Zhu C, Francisco JS, Zeng XC. First-Principles Molecular Dynamics Simulations of the Spontaneous Freezing Transition of 2D Water in a Nanoslit. J Am Chem Soc 2021; 143:8177-8183. [PMID: 34008407 DOI: 10.1021/jacs.1c03243] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
As with bulk ices, two-dimensional (2D) ices exhibit diverse crystalline structures, and the majority of these 2D structures have been predicted based on classical molecular dynamics (MD) simulations. Here, the spontaneous freezing transition of 2D liquid water within hydrophobic nanoslits is demonstrated for the first time using first-principles MD simulations. Various 2D ices are observed under different lateral pressure and temperature conditions. Notably, the liquid water confined to a 6.0 Å-wide nanoslit can spontaneously freeze into a monolayer ice consisting of an array of zigzag water chains at 2.5 GPa and 250 K. Moreover, within an 8.0 Å-wide nanoslit and at 4.0 GPa and 300 K, a previously unreported bilayer ice forms spontaneously that has a structure resembling that of the double surface layers of bulk ice-VII. Both 2D crystalline ices do not obey the ice rule, suggesting first-principles simulation can access a certain phase space that is not easily approached using classical simulations.
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Affiliation(s)
- Jian Jiang
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Yurui Gao
- Laboratory of Theoretical and Computational Nanoscience and Technology, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Weiduo Zhu
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Yuan Liu
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Chongqin Zhu
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing, 100190, P. R. China
| | - Joseph S Francisco
- Department of Earth & Environmental Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Xiao Cheng Zeng
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
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8
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Water under extreme confinement in graphene: Oscillatory dynamics, structure, and hydration pressure explained as a function of the confinement width. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114027] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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9
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Li S, Schmidt B. Replica exchange MD simulations of two-dimensional water in graphene nanocapillaries: rhombic versus square structures, proton ordering, and phase transitions. Phys Chem Chem Phys 2019; 21:17640-17654. [PMID: 31364628 DOI: 10.1039/c9cp00849g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The hydrogen bond patterns, proton ordering, and phase transitions of monolayer ice in two-dimensional hydrophobic confinement are fundamentally different from those found for bulk ice. To investigate the behavior of quasi-2D ice, we perform molecular dynamics simulations of water confined between fixed graphene plates at a distance of 0.65 nm. While experimental results are still limited and theoretical investigations are often based on a single, often empirically based force field model, this work presents a systematic study modeling the water-graphene interaction by effective Lennard-Jones potentials previously derived from high-level ab initio CCSD(T) calculations of water adsorbed on graphene [Phys. Chem. Chem. Phys., 2013, 15, 4995]. For the water-water interaction different water force fields, i.e. SPCE, TIP3P, TIP4P, TIP4P/ICE, and TIP5P, are used. The water occupancy of the graphene capillary at a pressure of 1000 MPa is determined to be between 13.5 and 13.9 water molecules per square nanometer, depending on the choice of the water force field. Based on these densities, we explore the structure and dynamics of quasi-2D water for temperatures ranging from 200 K to about 600 K for each of the five force fields. To ensure complete sampling of the configurational space and to overcome the barriers separating metastable structures, these simulations are based on the replica exchange molecular dynamics technique. We report different tetragonal hydrogen bond patterns, which are classified as nearly square or as rhombic. While many of these arrangements are essentially flat, in some cases puckered arrangements are found, too. Also the proton ordering of the quasi-2D water structures is considered, allowing us to identify them as ferroelectric, ferrielectric or antiferroelectric. For temperatures between 200 K and 400 K we find several second-order phase transitions from one ice structure to another, changing in many cases both the arrangements of the oxygen atoms and the proton ordering. For temperatures between 400 K and 600 K there are melting-like transitions from a monolayer of ice to a monolayer of liquid water. These first-order phase transitions have a latent heat between 3.4 and 4.0 kJ mol-1. Both the values of the transition temperatures and of the latent heats display considerable model dependence for the five different water models investigated here.
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Affiliation(s)
- Shujuan Li
- Institute for Mathematics, Freie Universität Berlin, Arnimallee 6, D-14195 Berlin, Germany.
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10
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Cai X, Xie WJ, Yang Y, Long Z, Zhang J, Qiao Z, Yang L, Gao YQ. Structure of water confined between two parallel graphene plates. J Chem Phys 2019; 150:124703. [DOI: 10.1063/1.5080788] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Xiaoxia Cai
- Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
| | - Wen Jun Xie
- Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
| | - Ying Yang
- Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
| | - Zhuoran Long
- Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
| | - Jun Zhang
- Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
| | - Zhuoran Qiao
- Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
| | - Lijiang Yang
- Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
| | - Yi Qin Gao
- Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
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11
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de Aquino BRH, Ghorbanfekr-Kalashami H, Neek-Amal M, Peeters FM. Ionized water confined in graphene nanochannels. Phys Chem Chem Phys 2019; 21:9285-9295. [DOI: 10.1039/c9cp00075e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
When confined between graphene layers, water in the presence of additional hydronium and hydroxide ions exhibits distinct properties such as ion layering structure determined by the channel size, disruption of the ion solvation shell, and slower ion recombination rate as compared to bulk water.
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Affiliation(s)
| | | | - M. Neek-Amal
- Department of Physics
- Shahid Rajaee Teacher Training University
- Lavizan
- Iran
| | - F. M. Peeters
- Department of Physics
- Universiteit Antwerpen
- B-2020 Antwerpen
- Belgium
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12
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Kaneko T, Bai J, Akimoto T, Francisco JS, Yasuoka K, Zeng XC. Phase behaviors of deeply supercooled bilayer water unseen in bulk water. Proc Natl Acad Sci U S A 2018; 115:4839-4844. [PMID: 29691325 PMCID: PMC5949004 DOI: 10.1073/pnas.1802342115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Akin to bulk water, water confined to an isolated nanoslit can show a wealth of new 2D phases of ice and amorphous ice, as well as unusual phase behavior. Indeed, 2D water phases, such as bilayer hexagonal ice and monolayer square ice, have been detected in the laboratory, confirming earlier computational predictions. Herein, we report theoretical evidence of a hitherto unreported state, namely, bilayer very low density amorphous ice (BL-VLDA), as well as evidence of a strong first-order transition between BL-VLDA and the BL amorphous ice (BL-A), and a weak first-order transition between BL-VLDA and the BL very low density liquid (BL-VLDL) water. The diffusivity of BL-VLDA is typically in the range of 10-9 cm2/s to 10-10 cm2/s. Similar to bulk (3D) water, 2D water can exhibit two forms of liquid in the deeply supercooled state. However, unlike supercooled bulk water, for which the two forms of liquid can coexist and merge into one at a critical point, the 2D BL-VLDL and BL high-density liquid (BL-HDL) phases are separated by the highly stable solid phase of BL-A whose melting line exhibits the isochore end point (IEP) near 220 K in the temperature-pressure diagram. Above the IEP temperature, BL-VLDL and BL-HDL are indistinguishable. At negative pressures, the metastable BL-VLDL exhibits a spatially and temporally heterogeneous structure induced by dynamic changes in the nanodomains, a feature much less pronounced in the BL-HDL.
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Affiliation(s)
- Toshihiro Kaneko
- Department of Mechanical Engineering, Tokyo University of Science, Noda 278-8510, Japan
- Research Institute for Science and Technology, Tokyo University of Science, Noda 278-8510, Japan
| | - Jaeil Bai
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588
| | - Takuma Akimoto
- Department of Physics, Tokyo University of Science, Noda 278-8510, Japan
| | - Joseph S Francisco
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588;
| | - Kenji Yasuoka
- Department of Mechanical Engineering, Keio University, Yokohama 223-8522, Japan
| | - Xiao Cheng Zeng
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588;
- Department of Chemical & Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588
- Department of Mechanical & Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
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13
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Zubeltzu J, Artacho E. Simulations of water nano-confined between corrugated planes. J Chem Phys 2017; 147:194509. [PMID: 29166107 DOI: 10.1063/1.5011468] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Water confined to nanoscale widths in two dimensions between ideal planar walls has been the subject of ample study, aiming at understanding the intrinsic response of water to confinement, avoiding the consideration of the chemistry of actual confining materials. In this work, we study the response of such nanoconfined water to the imposition of a periodicity in the confinement by means of computer simulations, both using empirical potentials and from first-principles. For that we propose a periodic confining potential emulating the atomistic oscillation of the confining walls, which allows varying the lattice parameter and amplitude of the oscillation. We do it for a triangular lattice, with several values of the lattice parameter: one which is ideal for commensuration with layers of Ih ice and other values that would correspond to more realistic substrates. For the former, the phase diagram shows an overall rise of the melting temperature. The liquid maintains a bi-layer triangular structure, however, despite the fact that it is not favoured by the external periodicity. The first-principles liquid is significantly affected by the modulation in its layering and stacking even at relatively small amplitudes of the confinement modulation. Beyond some critical modulation amplitude, the hexatic phase present in flat confinement is replaced by a trilayer crystalline phase unlike any of the phases encountered for flat confinement. For more realistic lattice parameters, the liquid does not display higher tendency to freeze, but it clearly shows inhomogeneous behaviour as the strength of the rugosity increases. In spite of this expected inhomogeneity, the structural and dynamical response of the liquid is surprisingly insensitive to the external modulation. Although the first-principles calculations give a more triangular liquid than the one observed with empirical potentials (TIP4P/2005), both agree remarkably well for the main conclusions of the study.
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Affiliation(s)
- Jon Zubeltzu
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
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14
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Zhu Y, Wang F, Wu H. Structural and dynamic characteristics in monolayer square ice. J Chem Phys 2017; 147:044706. [DOI: 10.1063/1.4995432] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- YinBo Zhu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - FengChao Wang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - HengAn Wu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230027, China
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15
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Structures and thermodynamics of water encapsulated by graphene. Sci Rep 2017; 7:2646. [PMID: 28572635 PMCID: PMC5453971 DOI: 10.1038/s41598-017-02582-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 04/13/2017] [Indexed: 11/08/2022] Open
Abstract
Understanding phase behaviors of nanoconfined water has driven notable research interests recently. In this work, we examine water encapsulated under a graphene cover that offers an ideal testbed to explore its molecular structures and thermodynamics. We find layered water structures for up to ~1000 trapped water molecules, which is stabilized by the spatial confinement and pressure induced by interfacial adhesion. For monolayer encapsulations, we identify representative two-dimensional crystalline lattices as well as defects therein. Free energy analysis shows that the structural orders with low entropy are compensated by high formation energies due to the pressurized confinement. There exists an order-to-disorder transition for this condensed phase at ~480-490 K, with a sharp reduction in the number of hydrogen bonds and increase in the entropy. Fast diffusion of the encapsulated water demonstrates anomalous temperature dependence, indicating the solid-to-fluid nature of this structural transition. These findings offer fundamental understandings of the encapsulated water that can be used as a pressurized cell with trapped molecular species, and provide guidance for practical applications with its presence, for example, in the design of nanodevices and nanoconfined reactive cells.
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16
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Zhu Y, Wang F, Wu H. Superheating of monolayer ice in graphene nanocapillaries. J Chem Phys 2017; 146:134703. [DOI: 10.1063/1.4979478] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- YinBo Zhu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - FengChao Wang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - HengAn Wu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230027, China
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17
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Zhao W, Francisco JS, Zeng XC. CO Separation from H 2 via Hydrate Formation in Single-Walled Carbon Nanotubes. J Phys Chem Lett 2016; 7:4911-4915. [PMID: 27934039 DOI: 10.1021/acs.jpclett.6b02443] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Hydrogen is an alternative fuel without generating greenhouse gas or other harmful emissions. Industrial hydrogen production, however, always contains a small fraction of carbon monoxide (CO) (∼0.5-2%) that must be removed for use in fuel cells. Here, we present molecular dynamics simulation evidence on facile separation of CO from H2 at ambient pressure via the formation of quasi-one-dimensional (Q1D) clathrate hydrates within single-walled carbon nanotubes (SW-CNTs). At ambient pressure, Q1D CO (or H2) clathrates in SW-CNTs are formed spontaneously when the SW-CNTs are immersed in CO (or H2) aqueous solution. More interestingly, for the CO/H2 aqueous solution, highly preferential adsorption of CO over H2 occurs within the octagonal or nonagonal ice nanotubes inside of SW-CNTs. These results suggest that the formation of Q1D hydrates within SW-CNTs can be a viable and safe method for the separation of CO from H2, which can be exploited for hydrogen purification in fuel cells.
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Affiliation(s)
- Wenhui Zhao
- Department of Physics, Ningbo University , Ningbo, Zhejiang 315211, China
- Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemical Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Joseph S Francisco
- Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
| | - Xiao Cheng Zeng
- Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemical Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
- Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
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18
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Zhu Y, Wang F, Wu H. Buckling failure of square ice-nanotube arrays constrained in graphene nanocapillaries. J Chem Phys 2016; 145:054704. [PMID: 27497569 DOI: 10.1063/1.4959902] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Graphene confinement provides a new physical and mechanical environment with ultrahigh van der Waals pressure, resulting in new quasi-two-dimensional phases of few-layer ice. Polymorphic transition can occur in bilayer constrained water/ice system. Here, we perform a comprehensive study of the phase transition of AA-stacked bilayer water constrained within a graphene nanocapillary. The compression-limit and superheating-limit (phase) diagrams are obtained, based on the extensive molecular-dynamics simulations at numerous thermodynamic states. Liquid-to-solid, solid-to-solid, and solid-to-liquid-to-solid phase transitions are observed in the compression and superheating of bilayer water. Interestingly, there is a temperature threshold (∼275 K) in the compression-limit diagram, which indicates that the first-order and continuous-like phase transitions of bilayer water depend on the temperature. Two obviously different physical processes, compression and superheating, display similar structural evolution; that is, square ice-nanotube arrays (BL-VHDI) will bend first and then transform into bilayer triangular AA stacking ice (BL-AAI). The superheating limit of BL-VHDI exhibits local maxima, while that of BL-AAI increases monotonically. More importantly, from a mechanics point of view, we propose a novel mechanism of the transformation from BL-VHDI to BL-AAI, both for the compression and superheating limits. This structural transformation can be regarded as the "buckling failure" of the square-ice-nanotube columns, which is dominated by the lateral pressure.
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Affiliation(s)
- YinBo Zhu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - FengChao Wang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - HengAn Wu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230027, China
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19
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Zubeltzu J, Corsetti F, Fernández-Serra MV, Artacho E. Continuous melting through a hexatic phase in confined bilayer water. Phys Rev E 2016; 93:062137. [PMID: 27415238 DOI: 10.1103/physreve.93.062137] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Indexed: 04/19/2023]
Abstract
Liquid water is not only of obvious importance but also extremely intriguing, displaying many anomalies that still challenge our understanding of such an a priori simple system. The same is true when looking at nanoconfined water: The liquid between constituents in a cell is confined to such dimensions, and there is already evidence that such water can behave very differently from its bulk counterpart. A striking finding has been reported from computer simulations for two-dimensionally confined water: The liquid displays continuous or discontinuous melting depending on its density. In order to understand this behavior, we have analyzed the melting exhibited by a bilayer of nanoconfined water by means of molecular dynamics simulations. At high density we observe the continuous melting to be related to the phase change of the oxygens only, with the hydrogens remaining liquidlike throughout. Moreover, we find an intermediate hexatic phase for the oxygens between the liquid and a triangular solid ice phase, following the Kosterlitz-Thouless-Halperin-Nelson-Young theory for two-dimensional melting. The liquid itself tends to maintain the local structure of the triangular ice, with its two layers being strongly correlated yet with very slow exchange of matter. The decoupling in the behavior of the oxygens and hydrogens gives rise to a regime in which the complexity of water seems to disappear, resulting in what resembles a simple monoatomic liquid. This intrinsic tendency of our simulated water may be useful for understanding novel behaviors in other confined and interfacial water systems.
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Affiliation(s)
- Jon Zubeltzu
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
| | - Fabiano Corsetti
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
- Department of Materials and the Thomas Young Centre for Theory and Simulation of Materials, Imperial College London, London SW7 2AZ, United Kingdom
| | - M V Fernández-Serra
- Physics and Astronomy Department, SUNY Stony Brook University, New York 11794-3800, USA
| | - Emilio Artacho
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
- Theory of Condensed Matter, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
- Basque Foundation for Science Ikerbasque, 48011 Bilbao, Spain
- Donostia International Physics Center, 20018 Donostia-San Sebastián, Spain
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20
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Corsetti F, Matthews P, Artacho E. Structural and configurational properties of nanoconfined monolayer ice from first principles. Sci Rep 2016; 6:18651. [PMID: 26728125 PMCID: PMC4700474 DOI: 10.1038/srep18651] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 11/23/2015] [Indexed: 12/13/2022] Open
Abstract
Understanding the structural tendencies of nanoconfined water is of great interest for nanoscience and biology, where nano/micro-sized objects may be separated by very few layers of water. Here we investigate the properties of ice confined to a quasi-2D monolayer by a featureless, chemically neutral potential, in order to characterize its intrinsic behaviour. We use density-functional theory simulations with a non-local van der Waals density functional. An ab initio random structure search reveals all the energetically competitive monolayer configurations to belong to only two of the previously-identified families, characterized by a square or honeycomb hydrogen-bonding network, respectively. We discuss the modified ice rules needed for each network, and propose a simple point dipole 2D lattice model that successfully explains the energetics of the square configurations. All identified stable phases for both networks are found to be non-polar (but with a topologically non-trivial texture for the square) and, hence, non-ferroelectric, in contrast to previous predictions from a five-site empirical force-field model. Our results are in good agreement with very recently reported experimental observations.
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Affiliation(s)
- Fabiano Corsetti
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
- Department of Materials and the Thomas Young Centre for Theory and Simulation of Materials, Imperial College London, London SW7 2AZ, United Kingdom
| | | | - Emilio Artacho
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
- Theory of Condensed Matter, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
- Basque Foundation for Science Ikerbasque, 48011 Bilbao, Spain
- Donostia International Physics Center, 20018 Donostia-San Sebastián, Spain
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21
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Zhu Y, Wang F, Bai J, Zeng XC, Wu H. AB-stacked square-like bilayer ice in graphene nanocapillaries. Phys Chem Chem Phys 2016; 18:22039-46. [DOI: 10.1039/c6cp03061k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Water, when constrained between two graphene sheets and under ultrahigh pressure, can manifest dramatic differences from its bulk counterparts such as the van der Waals pressure induced water-to-ice transformation, known as the metastability limit of two-dimensional (2D) liquid.
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Affiliation(s)
- YinBo Zhu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials
- Department of Modern Mechanics
- CAS Center for Excellence in Nanoscience
- University of Science and Technology of China
- Hefei
| | - FengChao Wang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials
- Department of Modern Mechanics
- CAS Center for Excellence in Nanoscience
- University of Science and Technology of China
- Hefei
| | - Jaeil Bai
- Department of Chemistry
- University of Nebraska-Lincoln
- USA
| | - Xiao Cheng Zeng
- Department of Chemistry
- University of Nebraska-Lincoln
- USA
- Hefei National Laboratory for Physical Sciences at Microscale and Collaborative Innovation Center of Chemistry for Energy Materials
- University of Science and Technology of China
| | - HengAn Wu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials
- Department of Modern Mechanics
- CAS Center for Excellence in Nanoscience
- University of Science and Technology of China
- Hefei
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