Adsorption and reactions of tetraethoxysilane (TEOS) on clean and water-dosed titanium dioxide (110)

Gamble, Lara J.; Hugenschmidt, Markus B.; Campbell, C. T.; Jurgens, Teresa A.; Rogers, J. W.

doi:10.1021/ja00078a055

Cited by 38 publications

(63 citation statements)

References 3 publications

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“…28,29 The cleaning procedure has been shown to produce a nearly stoichiometric and well-ordered TiO 2 (110) surface, which was checked with XPS and LEED. The unit cell of the TiO 2 (110) surface has dimensions of 2.96 Å ϫ 6.49 Å, giving 5.2ϫ10 14 unit cells per cm 2 of surface area.…”

Section: Methodsmentioning

confidence: 99%

Cesium adsorption onTiO2(110)

Grant

Campbell

1997

Phys. Rev. B

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The adsorption of Cs on a TiO 2 (110) rutile surface was investigated at 130-800 K using x-ray photoelectron spectroscopy, x-ray excited Auger electron spectroscopy, temperature-programmed desorption, work-function, and band-bending measurements. Below room temperature, the Cs displays a Stranski-Krastanov growth mode, with the completion of a uniform monolayer ͑ML͒ containing (6Ϯ2)ϫ10 14 Cs adatoms per cm 2 , followed by the growth of three-dimensional clusters of Cs that cover only a small fraction of the surface. The Cs in the first ϳ 1 2 ML is very cationic, donating electron density to the TiO 2 . Most of this charge is localized near the topmost atomic layers, with Ti 4ϩ ions being reduced to Ti 3ϩ . This gives rise to a local dipole moment of the adsorbate-substrate complex of ϳ6D at ϳ0.1 ML. However, a small part of the charge transferred to the substrate also goes much deeper into the solid, giving rise to downward band bending of ϳ0.2-0.3 eV. This band bending nearly saturates at ϳ0.05 ML. The local dipole moment of the alkali-metal-substrate complex decreases smoothly with coverage in the first ML, due to dipole-dipole repulsions and their consequent mutual depolarization, similar to transition-metal surfaces. This gives rise to a rapid and smooth decrease in the heat of adsorption with coverage from Ͼ208kJ/mol down to ϳ78kJ/mol.

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Section: Methodsmentioning

confidence: 99%

Cesium adsorption onTiO2(110)

Grant

Campbell

1997

Phys. Rev. B

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“…Previous studies have demonstrated that a wide range of functional groups can be anchored onto oxide surfaces. These anchoring groups include silanes, [12][13][14][15] carboxylic acids, 16,17 phosphonic acids, [18][19][20][21] and alkenes. 22,23 However, each of these groups while offering some advantages also has limitations.…”

Section: Introductionmentioning

confidence: 99%

Versatile grafting chemistry for creation of stable molecular layers on oxides

et al. 2012

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“…Some previous experiments were conducted by other groups to investigate the mechanism of TEOS adsorption by thermal desorption spectroscopy, and their results showed that TEOS adsorbs on titania surface by a dissociative reaction and produces an intermediate mixture of adsorbed di-and triethoxysilanes. 38,39 However, various theoretical calculations of adsorption energy for small molecules ͑water, ammonia, and alcohol͒ were performed by first principles calculations 40,41 and a semiempirical method. 42,43 These reports have presented the adsorption energy of water and methanol on titania surface.…”

Section: Simulation Detailsmentioning

confidence: 99%

Grand canonical Monte Carlo simulation study of capillary condensation between nanoparticles

Kim

Ehrman

2007

The Journal of Chemical Physics

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Capillary condensation at the nanoscale differs from condensation in the bulk phase, because it is a strong function of surface geometry and gas-surface interactions. Here, the effects of geometry on the thermodynamics of capillary condensation at the neck region between nanoparticles are investigated via a grand canonical Monte Carlo simulation using a two-dimensional lattice gas model. The microscopic details of the meniscus formation on various surface geometries are examined and compared with results of classical macromolecular theory, the Kelvin equation. We assume that the system is composed of a lattice gas and the surfaces of two particles are approximated by various shapes. The system is modeled on the basis of the molecular properties of the particle surface and lattice gas in our system corresponding to titania nanoparticles and tetraethoxy orthosilicate molecules, respectively. This system was chosen in order to reasonably emulate our previous experimental results for capillary condensation on nanoparticle surfaces. Qualitatively, our simulation results show that the specific geometry in the capillary zone, the surface-surface distance, and the saturation ratio are important for determining the onset and broadening of the liquid meniscus. The meniscus height increases continuously as the saturation ratio increases and the meniscus broadens faster above the saturation ratio of 0.90. The change of the radius of curvature of the particle surface affects the dimensions of the capillary zone, which drives more condensation in narrow zones and less condensation in wide zones. The increase of surface-surface distance results in the decrease of the meniscus height or even the disappearance of the meniscus entirely at lower saturation ratios. These effects are significant at the nanoscale and must be carefully considered in order to develop predictive relationships for meniscus height as a function of saturation conditions.

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Adsorption and reactions of tetraethoxysilane (TEOS) on clean and water-dosed titanium dioxide (110)

Cited by 38 publications

References 3 publications

Cesium adsorption onTiO2(110)

Cesium adsorption onTiO2(110)

Versatile grafting chemistry for creation of stable molecular layers on oxides

Grand canonical Monte Carlo simulation study of capillary condensation between nanoparticles

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