Hydrogen bonding and molecular orientations across thin water films on sapphire

doi:10.1016/j.jcis.2019.08.028

Journal of Colloid and Interface Science

Volume 555, 1 November 2019, Pages 810-817

https://doi.org/10.1016/j.jcis.2019.08.028 Get rights and content

Abstract

Hypothesis

Water vapor binding to metal oxide surfaces produces thin water films with properties controlled by interactions with surface hydroxo sites. Hydrogen bonding populations vary across films and induce different molecular orientations than at the surface of liquid water. Identifying these differences can open possibilities for tailoring film-mediated catalytic reactions by choice of the supporting metal oxide substrate.

Experiments

The (0001) face of a single sapphire (α-Al₂O₃) sample exposed to water vapor and the surface of liquid water were probed by polarization dependent Sum Frequency Generation-Vibration Spectroscopy (SFG-VS). Molecular dynamics (MD) provided insight into the hydrogen bond populations and molecular orientations across films and liquid water.

Findings

SFG-VS revealed a submonolayer film on sapphire exposed to 43% relative humidity (R.H.), and a multilayer film at 78% R.H. Polarization dependent SFG-VS spectra showed that median tilt angles of free O single bond H bonds on the top of films are at ∼43° from the normal of the (0001) face but at 38° on neat liquid water. These values align with MD simulations, which also show that up to 36% of all OH bonds on films are free. This offers new means for understanding how interfacial reactions on sapphire-supported water films could contrast with those involving liquid water.

Graphical abstract

Introduction

Metal oxide surfaces exposed to atmospheric water stabilize thin water films of various thickness and degrees of organization (Fig. 1) [1], [2], [3], [4], [5], [6]. These films can solubilize gases and ions in highly unique ways, and host reaction of crucial importance to environmental and technological processes where solids are exposed to atmospheric water vapor. Advancing knowledge on the nature of water molecules in these films is essential for the scientific community’s pursuit of understanding processes relevant to fields as varied as vadose zone geochemistry, atmospheric cloud chemistry, (photo)catalysis, microfluidics, rheology and tribology.

Water films develop when water vapor (i) binds directly onto metal oxide surface sites, forming the first few layer waters of films (adsorption regime), and (ii) grow further via water-water interactions (condensation regime) [7]. Moving current-day boundaries in this area requires combined knowledge from the metal oxide/water [8], [9], [10], [11], [12], [13], [14], [15], [16], [17] and water/air literature [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], two fields that have received far more attention than material-supported water films. Knowledge of hydrogen bond populations and of water orientation across supported water films remains, as such, increasingly needed as new possibilities are emerging for understanding processes across and on these films (e.g. gas dissolution, photosensitive reactions, monolayer assembly). One notable example of where such knowledge is needed includes a recent study showing how water film thickness tailors CO oxidation on gold [28].

Although experimental work involving oxide nanoparticles [29], [30] can be advantageous for addressing water binding phenomena, interparticle capillary condensation can add complexity to the host of reactions under study. Single oriented surfaces minimize these contributions and create possibilities for following film growth mechanisms. Additionally, they offer an ideal setting for directly probing the water/air component of water films. They consequently provide possibilities for advancing knowledge on the chemistry of the topmost water molecules responsible for film growth and gas exchange reactions.

In this study, Sum Frequency Generation Vibrational Spectroscopy (SFG-VS) and molecular modeling were used to explore water films formed by the adsorption and condensation of water vapor on the basal (0001) face (C-plane) of sapphire (α-Al₂O₃) [18], [19], [22], [25], [31], [32], [33], [34]. The hydroxylated form of this face is of great significance to earth sciences and technology as it exposes free and weakly-hydrogen bonded hydroxyl groups [35], [36], [37] responsible for the attachment of water (Fig. 1) and a score of solvent-mediated catalytic reactions.

This SFG-VS work provides insight into the dominant hydroxyl functional groups outcropping the (0001) face, and of the water films formed by adsorption and condensation of water vapor. MD simulations provide insight into hydrogen bond populations formed in and across the films, especially to contrast with populations formed in bulk liquid water. These properties will also be compared to those of the water/air interfacial region of neat water, and will account for a recently-proposed [38] modification of a geometric definition of hydrogen bonds in this region. A theory-supported analysis of the polarization dependence of SFG-VS spectra will demonstrate how the orientation of free O single bond H bonds in the top portions of both sapphire-supported water films differs from that of the surface of liquid water. This suggestion promotes further polarization dependent SFG-VS as a means for tracking the orientation of the topmost water molecules during (e.g. gas exchange, (photo)catalysis) reactions. This should be especially important for future studies aimed at testing hypotheses linking the orientation of these topmost water molecules to mechanisms and energetics of interfacial reactions.

Section snippets

Synthetic sapphire

Synthetic sapphire samples were purchased from SurfaceNet GmbH (Rheine, Germany). The samples were grown with the Kyropoulos crystal growth method [39], cut as 3 × 3 × 3 mm cubes, and mechanically and chemically polished along the (0001) face. The orientation of the face was confirmed by high resolution digital Laue (Photonic Science). X-ray photoelectron spectroscopy (XPS; Kratos Axis Ultra) confirmed that the sample surfaces was terminated by Al₂O₃ and surface hydroxo groups, although with a

SFG-VS

SFG-VS measurements (Fig. 2) of the dry (0 R.H.) sapphire surface under ssp polarization detected terminating OH functional groups [35], [51], [65], [66], [67], [68] through a single, yet broad, band centered at 3700 cm⁻¹. This is consistent with previous SFG-VS work [35], [36], [69] on the hydroxylated (0001) face of α-Al₂O₃ and, despite possible variations in properties (roughness, co-existence of hydrophobic nanopore [37]) that can arise from differences in sample preparation, the band is

Conclusions

This work provides evidence that water films on sapphire develop considerably different solvation environments than at the surface and bulk of liquid water. This was seen in the orientation of the topmost region of the water surfaces — with a tilt angle centered at 43° for films on sapphire and 38° on neat water — down to the deeper portions of the films where water molecules are hydrogen bonded to μ–OH groups. It was also manifested in the greater proportions of free OH bonds of films, which

Acknowledgements

This work was supported by the Swedish research council, Sweden to J.-F.B. (VR 2016-03808), the Carl-Tryggers Foundations, Sweden and the Kempe Foundations, Sweden. A portion of this research was conducted using the resources of High Performance Computing Centre North (HPC2N) at Umeå University. All SFG-VS work was performed using EMSL (Ringgold ID 130367), a DOE Office of Science User Facility sponsored by the Office of Biological and Environmental Research, User Project # 49764 to J.-F.B.

References (78)

D.D. Do et al.
A model for water adsorption in activated carbon
Carbon
(2000)
J.G. Catalano
Weak interfacial water ordering on isostructural hematite and corundum (001) surfaces
Geochim. Cosmochim. Acta
(2011)
X. Song et al.
Water vapor interactions with FeOOH particle surfaces
Chem. Phys. Lett.
(2013)
M.R. Conde
Properties of aqueous solutions of lithium and calcium chlorides: formulations for use in air conditioning equipment design
Int. J. Therm. Sci.
(2004)
J. Lutzenkirchen et al.
A set-up for simultaneous measurement of second harmonic generation and streaming potential and some test applications
J. Colloid Interface Sci.
(2018)
J. Lutzenkirchen et al.
The surface chemistry of sapphire-c: a literature review and a study on various factors influencing its IEP
Adv. Colloid Interface Sci.
(2018)
R.W. Hockney et al.
Quiet high-resolution computer models of a plasma
J. Comp. Phys.
(1974)
A.K. Soper et al.
A new determination of the structure of water at 25°C
Chem. Phys.
(1986)
G. Busca
The surface of transitional aluminas: a critical review
Catal. Today
(2014)
D.E. Moore et al.
Crystallographic controls on the frictional behavior of dry and water-saturated sheet structure minerals
J. Geophys. Res.: Solid Earth
(2004)

D. Argyris et al.

Molecular structure and dynamics in thin water films at the silica and graphite surfaces

J. Phys. Chem. C

(2008)

G.E. Ewing

Ambient thin film water on insulator surfaces

Chem. Rev.

(2006)

G.A. Kimmel et al.

Polarization- and azimuth-resolved infrared spectroscopy of water on TiO₂(110): anisotropy and the hydrogen-bonding network

J. Phys. Chem. Lett.

(2012)

N.G. Petrik et al.

Hydrogen bonding, H-D exchange, and molecular mobility in thin water films on TiO₂(110)

Phys. Rev. Lett.

(2007)

J.C.C. Santos et al.

Interaction of water with the gypsum (010) surface: structure and dynamics from nonlinear vibrational spectroscopy and Ab initio molecular dynamics

J. Am. Chem. Soc.

(2018)

J. Sung et al.

The interfacial structure of water/protonated alpha-Al₂O₃ (11(2)over-bar0) as a function of pH

J. Phys.-Cond. Matt.

(2012)

J. Sung et al.

Effect of pH on the water/α-Al₂O₃(11̅02) interface structure studied by sum-frequency vibrational spectroscopy

J. Phys. Chem. C

(2011)

J. Sung et al.

Surface structure of protonated R-sapphire (1102) studied by sum-frequency vibrational spectroscopy

J. Am. Chem. Soc.

(2011)

J.F. Boily

Water structure and hydrogen bonding at goethite/water interfaces: implications for proton affinities

J. Phys. Chem. C

(2012)

S.-Y. Ma et al.

Water film adsorbed on the α-Al₂O₃(0001) surface: structural properties and dynamical behaviors from first-principles molecular dynamics simulations

J. Phys. Chem. C

(2016)

N.N. Casillas-Ituarte et al.

Water, chloroform, acetonitrile, and atrazine adsorption to the amorphous silica surface studied by vibrational sum frequency generation spectroscopy

Chem. Phys. Lett.

(2009)

P.J. Eng et al.

Structure of the hydrated alpha-Al₂O₃ (0001) surface

Science

(2000)

M.F.C. Andrade et al.

Structure, polarization, and sum frequency generation spectrum of interfacial water on anatase TiO₂

J. Phys. Chem. Lett.

(2018)

A. Tuladhar et al.

Insights on interfacial structure, dynamics, and proton transfer from ultrafast vibrational sum frequency generation spectroscopy of the alumina(0001)/water interface

J. Phys. Chem. C

(2017)

Y. Nagata et al.

The surface roughness, but not the water molecular orientation varies with temperature at the water–air interface

Phys. Chem. Chem. Phys.

(2015)

J.D. Cyran et al.

Structure from dynamics: vibrational dynamics of interfacial water as a probe of aqueous heterogeneity

J. Phys. Chem. B

(2018)

O. Björneholm et al.

Water at Interfaces

Chem. Rev.

(2016)

I.V. Stiopkin et al.

Hydrogen bonding at the water surface revealed by isotopic dilution spectroscopy

Nature

(2011)

M. Bonn et al.

Molecular structure and dynamics of water at the water-air interface studied with surface-specific vibrational spectroscopy

Ang. Chem. Int. Ed.

(2015)

C.D. Wick et al.

The effect of polarizability for understanding the molecular structure of aqueous interfaces

J. Chem. Theo. Comp.

(2007)

Q. Du et al.

Vibrational spectroscopy of water at the vapor/water interface

Phys. Rev. Lett.

(1993)

W. Gan et al.

Polarization and experimental configuration analyses of sum frequency generation vibrational spectra, structure, and orientational motion of the air/water interface

J. Chem. Phys.

(2006)

R.R. Feng et al.

Reorientation of the “free OH” group in the top-most layer of air/water interface of sodium fluoride aqueous solution probed with sum-frequency generation vibrational spectroscopy

J. Chem. Phys.

(2014)

D. Verreault et al.

From conventional to phase-sensitive vibrational sum frequency generation spectroscopy: probing water organization at aqueous interfaces

J. Phys. Chem. Lett.

(2012)

J. Saavedra et al.

Controlling activity and selectivity using water in the Au-catalysed preferential oxidation of CO in H₂

Nat. Chem.

(2016)

X. Song et al.

Water vapor adsorption on goethite

Environ. Sci. Technol.

(2013)

G.L. Richmond

Structure and bonding of molecules at aqueous surfaces

Ann. Rev. Phys. Chem.

(2001)

Y. Nagata et al.

Molecular modeling of water interfaces: from molecular spectroscopy to thermodynamics

J. Phys. Chem. B

(2016)

A.M. Jubb et al.

Environmental Chemistry at Vapor/Water Interfaces: Insights from Vibrational Sum Frequency Generation Spectroscopy

Cited by (14)

Water film-mediated photocatalytic oxidation of oxalate on TiO<inf>2</inf>
2024, Journal of Catalysis
Water films on minerals under humid environment can be photocatalytic hotspots when exposed to sunlight or artificial sources of ultraviolet (and visible) radiation. In this study, we resolved the water film-mediated photocatalysis of oxalate adsorbed on TiO₂ using in situ infrared spectroscopy. We found that 0.5 to 4 monolayer- (ML) thick water films enhanced the photodecomposition rates of oxalate under 21 kPa O₂. We explained this through the combined actions of direct hole transfer, ligand-to-metal-charge transfer, as well as the production of hydroxyl radicals and reactive oxygen species. Rates were, however, substantially slower in the absence of O₂ because charge recombination, together with water film-mediated charge localization, disrupted hole transfer and hydroxyl radical production. Our work adds insight into the impact of humidity on controlling important photocatalytic processes in nature (drying soils, atmospheric aerosols), and technology (water and air treatment).
Vibrational spectroscopy of geochemical interfaces
2023, Surface Science Reports
Mineral/aqueous interfaces are ubiquitous in geochemistry and are employed for applications spanning catalysis to CO₂ sequestration. Small changes in interface morphology have been shown to induce large changes in ion mobility, surface charge, and solvent orientation, which affect the function of these geochemical interfaces. While our ability to probe buried interfaces has been advanced by surface specific and sensitive vibrational spectroscopies, the overlapping response of surface groups and water has made complete structural interpretations of these systems difficult. We believe that by highlighting recent experimental and computational works further progress can be made.
This review follows the evolution and current understanding of solvent and surface structure near SiO₂, Al₂O_3, CaF₂, and TiO₂/aqueous interfaces generated by modern spectroscopic and computational techniques. By comparing information gathered from a range of vibrational spectroscopies and simulations progress can be made in the following fields including and not limited to; geochemistry, industrial/petroleum chemistry, interface science, vibrational spectroscopy, computational chemistry, and materials science.
Water film-driven Mn (oxy)(hydr)oxide nanocoating growth on rhodochrosite
2022, Geochimica et Cosmochimica Acta
Citation Excerpt :
In this study, we identified phases formed in oxygenated water films contacted with rhodochrosite microparticles. We utilized recent advances in our understanding of water film formation and reactivity (Yesilbas and Boily, 2016; Boily et al., 2019; Yalcin et al., 2020) and spectroscopic signatures of Mn (oxy)(hydr)oxide phases (Potter and Rossman, 1979; Kohler et al., 1997; Kang et al., 2007; Kirillov et al., 2009; Elzinga, 2011; Ilton et al., 2016; Ling et al., 2017; Boumaiza et al., 2019; Ling et al., 2020) to monitor the time-, alkalinity- and water loading-dependence of Mn (oxy)(hydr)oxides grown in water films. By showing that transformations are possible in films of several water monolayers, our study adds new insight into the Mn (oxy)(hydr)oxide phases formed on rhodochrosite microparticles exposed to moist air.
Minerals exposed to moist air stabilize thin water films that drive a score of chemical reactions of great importance to water-unsaturated terrestrial environments. In this study, we identified Mn (oxy)(hydr)oxide nanocoatings formed by the dissolution, oxidation and precipitation of Mn in oxygenated water films grown on rhodochrosite (MnCO₃) microparticles. Nanocoatings that could be identified by vibrational spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and (scanning and transmission) electron microscopy formed in water films containing the equivalent of at least 7 monolayers (∼84 H₂O/nm²). These films were formed by exposing microparticles to moist air with at least 50% relative humidity (RH). Films of neutral pH reacted up to 14% of the Mn^II located in the topmost ∼5 nm region of the microparticles in atmospheres of up to 90% RH for 7 d. These reactions produced MnOOH, birnessite (MnO₂) and hausmannite (Mn₃O₄) nanoparticles of low crystallinity, while exposure to atmospheric air for 1 yr. converted only 2% of Mn^II in this region to MnOOH. In contrast, reactions in alkaline water films converted up to ∼75% of the Mn^II but only after 16 d of reaction. These films produced MnOOH and MnO₂ of low crystallinity, as well as crystalline hausmannite. Kinetic modeling of the time-resolved growth of the MnO stretching vibrational bands of these nanocoatings revealed two concurrent reaction processes. A 1^rst-order process was assigned to nucleation events terminating only after a few hours, and a 0-order process was assigned to the sustained growth of nanocoatings from these nuclei over longer reaction time. By identifying nanocoatings formed by water film-driven reactions on rhodochrosite, our study adds new insight into mineralogical transformations relevant to anoxic–oxic boundaries in water-unsaturated environments.
Measurement of Nanoscale Interfacial Contact Area Using Vibrational Spectroscopy
2024, arXiv
Water nanolayer facilitated solitary-wave-like blisters in MoS<inf>2</inf> thin films
2023, Nature Communications
Structural Anomality of the Adsorbed Water on Al-Doped Silica Revealed by Heterodyne-Detected Vibrational Sum-Frequency Generation Spectroscopy
2023, Journal of Physical Chemistry C

View all citing articles on Scopus

¹: Current address: Sanofi-Genzyme, 1 The Mountain Road, Framingham MA 01532, USA.

View full text

Hydrogen bonding and molecular orientations across thin water films on sapphire

Abstract

Hypothesis

Experiments

Findings

Graphical abstract

Introduction

Section snippets

Synthetic sapphire

SFG-VS

Conclusions

Acknowledgements

Carbon

Geochim. Cosmochim. Acta

Chem. Phys. Lett.

Int. J. Therm. Sci.

J. Colloid Interface Sci.

Adv. Colloid Interface Sci.

J. Comp. Phys.

Chem. Phys.

Catal. Today

Crystallographic controls on the frictional behavior of dry and water-saturated sheet structure minerals

J. Geophys. Res.: Solid Earth

Molecular structure and dynamics in thin water films at the silica and graphite surfaces

J. Phys. Chem. C

Ambient thin film water on insulator surfaces

Chem. Rev.

Polarization- and azimuth-resolved infrared spectroscopy of water on TiO2(110): anisotropy and the hydrogen-bonding network

J. Phys. Chem. Lett.

Hydrogen bonding, H-D exchange, and molecular mobility in thin water films on TiO2(110)

Phys. Rev. Lett.

Interaction of water with the gypsum (010) surface: structure and dynamics from nonlinear vibrational spectroscopy and Ab initio molecular dynamics

J. Am. Chem. Soc.

The interfacial structure of water/protonated alpha-Al2O3 (11(2)over-bar0) as a function of pH

J. Phys.-Cond. Matt.

Effect of pH on the water/α-Al2O3(11̅02) interface structure studied by sum-frequency vibrational spectroscopy

J. Phys. Chem. C

Surface structure of protonated R-sapphire (1102) studied by sum-frequency vibrational spectroscopy

J. Am. Chem. Soc.

Water structure and hydrogen bonding at goethite/water interfaces: implications for proton affinities

J. Phys. Chem. C

Water film adsorbed on the α-Al2O3(0001) surface: structural properties and dynamical behaviors from first-principles molecular dynamics simulations

J. Phys. Chem. C

Water, chloroform, acetonitrile, and atrazine adsorption to the amorphous silica surface studied by vibrational sum frequency generation spectroscopy

Chem. Phys. Lett.

Structure of the hydrated alpha-Al2O3 (0001) surface

Science

Structure, polarization, and sum frequency generation spectrum of interfacial water on anatase TiO2

J. Phys. Chem. Lett.

Insights on interfacial structure, dynamics, and proton transfer from ultrafast vibrational sum frequency generation spectroscopy of the alumina(0001)/water interface

J. Phys. Chem. C

The surface roughness, but not the water molecular orientation varies with temperature at the water–air interface

Phys. Chem. Chem. Phys.

Structure from dynamics: vibrational dynamics of interfacial water as a probe of aqueous heterogeneity

J. Phys. Chem. B

Water at Interfaces

Chem. Rev.

Hydrogen bonding at the water surface revealed by isotopic dilution spectroscopy

Nature

Molecular structure and dynamics of water at the water-air interface studied with surface-specific vibrational spectroscopy

Ang. Chem. Int. Ed.

The effect of polarizability for understanding the molecular structure of aqueous interfaces

J. Chem. Theo. Comp.

Vibrational spectroscopy of water at the vapor/water interface

Phys. Rev. Lett.

Polarization and experimental configuration analyses of sum frequency generation vibrational spectra, structure, and orientational motion of the air/water interface

J. Chem. Phys.

Reorientation of the “free OH” group in the top-most layer of air/water interface of sodium fluoride aqueous solution probed with sum-frequency generation vibrational spectroscopy

J. Chem. Phys.

From conventional to phase-sensitive vibrational sum frequency generation spectroscopy: probing water organization at aqueous interfaces

J. Phys. Chem. Lett.

Controlling activity and selectivity using water in the Au-catalysed preferential oxidation of CO in H2

Nat. Chem.

Water vapor adsorption on goethite

Environ. Sci. Technol.

Structure and bonding of molecules at aqueous surfaces

Ann. Rev. Phys. Chem.

Molecular modeling of water interfaces: from molecular spectroscopy to thermodynamics

J. Phys. Chem. B

Environmental Chemistry at Vapor/Water Interfaces: Insights from Vibrational Sum Frequency Generation Spectroscopy

Polarization- and azimuth-resolved infrared spectroscopy of water on TiO₂(110): anisotropy and the hydrogen-bonding network

Hydrogen bonding, H-D exchange, and molecular mobility in thin water films on TiO₂(110)

The interfacial structure of water/protonated alpha-Al₂O₃ (11(2)over-bar0) as a function of pH

Effect of pH on the water/α-Al₂O₃(11̅02) interface structure studied by sum-frequency vibrational spectroscopy

Water film adsorbed on the α-Al₂O₃(0001) surface: structural properties and dynamical behaviors from first-principles molecular dynamics simulations

Structure of the hydrated alpha-Al₂O₃ (0001) surface

Structure, polarization, and sum frequency generation spectrum of interfacial water on anatase TiO₂

Controlling activity and selectivity using water in the Au-catalysed preferential oxidation of CO in H₂