Study of translational, librational and intra-molecular motion of adsorbed liquid water monolayers at various TiO<sub>2</sub> interfaces

Kavathekar, Ritwik S.; English, Niall J.; MacElroy, J. M. D.

doi:10.1080/00268976.2011.627884

Cited by 29 publications

(31 citation statements)

References 19 publications

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“…52,54 English 117 reported order-of-magnitude lower diffusion coefficients near TiO 2 surfaces but did not attempt a systematic investigation of D lat as a function of s. Kavathekar et al 118 calculated diffusion coefficients near the same TiO 2 surfaces as in the present work and found large variations (from immobile to half the bulk value) in diffusion depending on the surface. The validity of those results is difficult to assess given that these simplified models neglect surface chemistry (hydroxylation).…”

Section: Diffusion In the Hydration Layersmentioning

confidence: 94%

Diffusion and reaction pathways of water near fully hydrated TiO2 surfaces from ab initio molecular dynamics

Agosta

Brandt

Lyubartsev

2017

The Journal of Chemical Physics

104

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Ab initio molecular dynamics simulations are reported for water-embedded TiO2 surfaces to determine the diffusive and reactive behavior at full hydration. A three-domain model is developed for six surfaces [rutile (110), (100), and (001), and anatase (101), (100), and (001)] which describes waters as “hard” (irreversibly bound to the surface), “soft” (with reduced mobility but orientation freedom near the surface), or “bulk.” The model explains previous experimental data and provides a detailed picture of water diffusion near TiO2 surfaces. Water reactivity is analyzed with a graph-theoretic approach that reveals a number of reaction pathways on TiO2 which occur at full hydration, in addition to direct water splitting. Hydronium (H3O+) is identified to be a key intermediate state, which facilitates water dissociation by proton hopping between intact and dissociated waters near the surfaces. These discoveries significantly improve the understanding of nanoscale water dynamics and reactivity at TiO2 interfaces under ambient conditions.

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Section: Diffusion In the Hydration Layersmentioning

confidence: 94%

Diffusion and reaction pathways of water near fully hydrated TiO2 surfaces from ab initio molecular dynamics

Agosta

Brandt

Lyubartsev

2017

The Journal of Chemical Physics

104

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“…In the case of titania-water, these studies have included orientations of surface-water dipoles [15], their vibrational spectra [16], kinetics of their hydrogen bonding arrangements [17], ion adsorption [18], electric double layer structure [19][20][21], surface protonation effects [22], and spatial distribution functions [23]. In terms of Density Functional Theory (DFT)-level calculations for titania-water interfaces, particularly from ab initio MD (AIMD), a range of surfaces have been simulated from partial to full coverage, and multiple water layers [13,24].…”

Section: Introductionmentioning

confidence: 99%

Photo-active and dynamical properties of hematite (Fe2O3)–water interfaces: an experimental and theoretical study

English

Rahman

Wadnerkar

et al. 2014

Phys. Chem. Chem. Phys.

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The dynamical properties of physically and chemically adsorbed water molecules at pristine hematite-(001) surfaces have been studied by means of equilibrium Born-Oppenheimer molecular dynamics (BOMD) in the NVT ensemble at 298 K. The dissociation of water molecules to form chemically adsorbed species was scrutinised, in addition to 'hopping' or swapping events of protons between water molecules. Particular foci have been dynamical properties of the adsorbed water molecules and OH -and H 3 O + ions, the hydrogen bonds between protons in water molecules and the bridging oxygen atoms at the hematite surface, as well as the interactions between oxygen atoms in adsorbed water molecules and iron atoms at the hematite surface. Experimental results for photoelectrical current generation complement simulation findings of water dissociation.

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“…The decrease or even suppression of translational motion of adsorbed water has been also found by MD simulations in metals 56 and titanium oxide polymorphs. 57 Overall, the surface is stabilized by the formation of a tessellated icelike water layer, a strongly structured water layer with restricted dynamics. These three water regimens were also observed for Rutile and Cassiterite surfaces both from MD simulations and quasi-elastic neutron-scattering experiments.…”

Section: −2mentioning

confidence: 99%

Insight on Tricalcium Silicate Hydration and Dissolution Mechanism from Molecular Simulations

Manzano

Durgun

López‐Arbeloa

et al. 2015

ACS Appl. Mater. Interfaces

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Hydration of mineral surfaces, a critical process for many technological applications, encompasses multiple coupled chemical reactions and topological changes, challenging both experimental characterization and computational modeling. In this work, we used reactive force field simulations to understand the surface properties, hydration, and dissolution of a model mineral, tricalcium silicate. We show that the computed static quantities, i.e., surface energies and water adsorption energies, do not provide useful insight into predict mineral hydration because they do not account for major structural changes at the interface when dynamic effects are included. Upon hydration, hydrogen atoms from dissociated water molecules penetrate into the crystal, forming a disordered calcium silicate hydrate layer that is similar for most of the surfaces despite wide-ranging static properties. Furthermore, the dynamic picture of hydration reveals the hidden role of surface topology, which can lead to unexpected water tessellation that stabilizes the surface against dissolution. KEYWORDS: dissolution, hydration, molecular dynamics, surface properties, water adsorption, calcium silicate ■ INTRODUCTIONThe hydration and dissolution of minerals is of crucial importance for a broad range of natural and synthetic phenomena: from the stability of minerals and rocks in watersheds and aquifers, 1 to hydrogen production and other heterogeneous catalytic reactions, 2,3 to the production, utilization, and ultimate degradation of building materials, 4 and to the durability of biomaterials, 5 to name only a few examples. The key properties at play during dissolution are controlled by interfacial reactions between water molecules and the solid surfaces, which can be probed experimentally via techniques such as AFM, vertical scanning interferometry (VSI), and the study of isotope exchange or solute fluxes to provide general information regarding the reaction rates or qualitative information about the formation of steps, pitches, and so on. 6 However, in many applications, much more control over the hydration and dissolution is desired, such as the ability to moderate the rate 7 or preferentially favor the dissolution of one crystal facet over other.8 To achieve such control, a deeper understanding of the molecular mechanisms governing hydration and dissolution is necessary.In this work, we use atomic-scale simulations to study the hydration of a calcium orthosilicate. We take a multistep approach, which is critical to piece together the relevant physical processes underlying hydration and dissolution. First, we analyze the surface energies and water molecule adsorption, extending beyond traditional approaches in order to obtain a more accurate picture of these properties. Next, we compare these surface properties with the results obtained from simulating a realistic hydration process over a period of 2 ns. We discuss the differences between the static and dynamic pictures and show that topological changes render the properties of the f...

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Study of translational, librational and intra-molecular motion of adsorbed liquid water monolayers at various TiO₂ interfaces

Cited by 29 publications

References 19 publications

Diffusion and reaction pathways of water near fully hydrated TiO2 surfaces from ab initio molecular dynamics

Diffusion and reaction pathways of water near fully hydrated TiO2 surfaces from ab initio molecular dynamics

Photo-active and dynamical properties of hematite (Fe2O3)–water interfaces: an experimental and theoretical study

Insight on Tricalcium Silicate Hydration and Dissolution Mechanism from Molecular Simulations

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Study of translational, librational and intra-molecular motion of adsorbed liquid water monolayers at various TiO2 interfaces

Cited by 29 publications

References 19 publications

Diffusion and reaction pathways of water near fully hydrated TiO2 surfaces from ab initio molecular dynamics

Diffusion and reaction pathways of water near fully hydrated TiO2 surfaces from ab initio molecular dynamics

Photo-active and dynamical properties of hematite (Fe2O3)–water interfaces: an experimental and theoretical study

Insight on Tricalcium Silicate Hydration and Dissolution Mechanism from Molecular Simulations

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Study of translational, librational and intra-molecular motion of adsorbed liquid water monolayers at various TiO₂ interfaces