Comment on “Structure and dynamics of liquid water on rutile TiO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>(110)”

Wesolowski, David J.; Sofo, Jorge O.; Bandura, Andrei V.; Zhang, Zhan; Mamontov, Eugene; Předota, Milan; Kumar, Nitin; Kubicki, James D.; Kent, Paul; Vlček, Lukáš; Machesky, Michael L.; Fenter, Paul; Cummings, Peter T.; Anovitz, Lawrence M.; Skelton, Adam A.; Rosenqvist, Jörgen

doi:10.1103/physrevb.85.167401

Cited by 50 publications

(27 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…43,44,50 Here, we find two (hard) layers closest to the surface and one soft outer layer, in good agreement with previous studies. 52,105 On rutile (001), there are fourth and fifth ordered water layers (L 4 , L 5 ) at 6 and 8 Å, respectively.…”

Section: Hard and Soft Hydration Layerssupporting

confidence: 81%

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

View full text Add to dashboard Cite

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.

show abstract

Section: Hard and Soft Hydration Layerssupporting

confidence: 81%

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

View full text Add to dashboard Cite

show abstract

“…Nguyen et al [36] have improved the DFT treatment of hematite-water interfaces by use of PBE+U. In many cases, very low energy barriers were found for water dissociation on hematite-001 surfaces, confirming experimental reports of widespread room-temperature dissociation of water on hematite-001 [36]; this is in some contrast to the debate as to the dominance of physical or chemical water adsorption on rutile-110 at room temperature [37][38][39]. However, to the best of our knowledge, there has been no AIMD study of the water-hematite interface, which is needed to capture the rich physic-complexity of roomtemperature chemical adsorption and the dynamical properties of the surface hematite layers, along with those of the water.…”

Section: Introductionmentioning

confidence: 71%

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.

View full text Add to dashboard Cite

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.

show abstract

“…TH and BH are still forming strong H-bonds, as is evident from the broad stretching bands measured and reproduced by the simulation in this range ( Figure 3D; blue line), but these bonds are predominantly with L 2 H 2 O through L 1 −L 2 interlayer interactions ( Figure 1A). Likewise, L 1 H 2 O dissociation still occurs, but via proton transfers from TW to L 2 to BO, rather than directly from TW to BO, 24 leading to an average state of 60% L 1 dissociation in the full sample (for comparison, the fully hydrated α-TiO 2 (110) surface has been reported to exhibit 0−30% L 1 dissociation [23][24][25]27,45 ). The INS spectrum contains no spatial information, but we find from the simulations that the lower energy end of the O−H stretching band is populated by species with H-bonds formed between L 1 and L 2 , while the upper end is populated by the H 2 O molecules in L 3 (see text in the Supporting Information).…”

Section: ■ Results and Discussionmentioning

confidence: 96%

“…The degree of dissociation of L 1 corresponds to a dynamic equilibrium driven by proton transfers between the associated and dissociated configurations, which depends on temperature, hydration level, 24 and pH, if liquid water is present. 25 Upon further hydration, a second (L 2 ) and third layer (L 3 ) will form whose structure depends on the degree of dissociation of L 1 . These layers are defined by distinct minima in the axial density profile of oxygen atoms perpendicular to the surface derived from our previous results, 36,37,43 and constitute 1 ML in L 1 , ∼1.7 ML in L 2 , and ∼1.3 ML in L 3 per Sn 2 O 4 (110) surface unit area.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Vibrational Density of States of Strongly H-Bonded Interfacial Water: Insights from Inelastic Neutron Scattering and Theory

et al. 2014

Self Cite

View full text Add to dashboard Cite

The molecular scale interaction between water and an oxide surface depends on the strength of the surface hydrogen bonds (Hbonds) through a subtle interplay among surface structure, surface atom polarity, and orientation of sorbed species. Tin oxide (SnO 2 ) in the rutile structure is an important catalytic and gas-sensing material, and its surface properties have been the subject of intense scrutiny. Here we show that the vibrational dynamics of H 2 O and OH sorbed on SnO 2 nanoparticles, probed with inelastic neutron scattering and analyzed with ab initio molecular dynamics, reveals very strong surface H-bonds, with a formation enthalpy twice that of liquid water. This unusually strong interaction results in (i) decoupling of the hydrated surface from additional water layers due to an epitaxial screening layer of H 2 O and OH species, (ii) high energy of OH wagging modes that provides an experimental indicator of surface H-bond strengths, and (iii) high proton exchange rates at the interface. H-bonding energetics and interfacial structures also control the average degree of dissociation of sorbed water. The close agreement in the vibrational density of states measured experimentally and generated in silico provides validation of the theory, while the atomistic simulations provide atomic/molecular-level details of individual species contributions to the observed spectrum. Together, these integrated studies provide definitive insights into the role of H-bonds in controlling the structure, dynamics, and reactivity of metal oxide/water interfaces. O xide−water interfaces are ubiquitous in heterogeneous catalysis, 1−6 protein folding, 7 environmental remediation, 1 mineral growth and dissolution, 8,9 and light−energy conversion in solar cells. 3−5,10 In all these systems, the structure and properties of water at the interface determine and control the specific chemical processes. 6 The (110) surfaces of cassiterite (SnO 2 ) and isostructural rutile (α-TiO 2 ) are prototypical oxide surfaces that have been intensely studied. These materials are widely used in catalysis, gas sensing, pigments, and many other applications. 1,3−6,8−13 However, the interpretation at the molecular level of the interfacial structures and dynamics remains highly controversial. Particularly the sorption energy, the strength of hydrogen bonds (H-bonds), and the degree of water dissociation upon adsorption are among the most discussed quantities. For instance, thermochemistry 14−17 and corresponding inelastic neutron scattering (INS) analyses on hydrated α-TiO 2 and SnO 2 nanoparticles 18−20 suggest that the higher surface energy of α-TiO 2 leads to stronger surface water interactions as compared to SnO 2 . On the other hand, theoretical predictions indicate that SnO 2 (110) interacts more strongly with water molecules than α-TiO 2 (110), with dissociative adsorption being thermodynamically favored on SnO 2 (110). 3,4,13,21−29 The degree of dissociation depends on the strength of the Hbond network at the interface 20−24,27 as determined by t...

show abstract

Comment on “Structure and dynamics of liquid water on rutile TiO2(110)”

Cited by 50 publications

References 42 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

Vibrational Density of States of Strongly H-Bonded Interfacial Water: Insights from Inelastic Neutron Scattering and Theory

Contact Info

Product

Resources

About