Hydrolytic stability of the Si–O–Ti bonds in the chemical assembly of titania nanostructures on silica surfaces

Соснов, Е. А.; Малков, А. А.; Малыгин, А. А.

doi:10.1070/rc2010v079n10abeh004112

Cited by 10 publications

(5 citation statements)

References 64 publications

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“…TiO 2 is heterogeneously nucleated directly at the surface of the silica walls (Figure e,f). This is a rare feature as during the liquid‐phase hydrolysis in the excess of water, water molecules formed a thin film on the modified matrix surface and easily cleaved the SiOTi bonds to afford discretized SiO 2 and TiO 2 phases . In the present synthetic path, we do not observe such phase segregation.…”

Section: Resultsmentioning

confidence: 55%

Bulk Photodriven CO₂ Conversion through TiO₂@Si(HIPE) Monolithic Macrocellular Foams

Bernadet

Tavernier

et al. 2019

Adv Funct Materials

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Operating photo-induced reactions exclusively on catalyst surfaces while not exploiting the full catalyst volume generates a major footprint penalty for the photocatalytic reactor and leads to an inefficient use of the catalytic material. Photonic investigations clearly show that the solid foams have a strongly multidiffusive character, with photons being significantly trapped within the sample cores while addressing a photon mean free path l t = 20.1 ± 1.3 µm. This 3D process both greatly limits back-reactions and promotes outstanding selectivity toward methane (around 80%) generation, and even ethane (around 18%) through C-C coupling reaction, with residual carbon monoxide and dihydrogen contents (around 2%). Silica-titania TiO 2 @Si(HIPE) self-standing macrocellular catalysts lead to optimal efficient thicknesses up to 20 times those of powders, thereby enhancing the way for real 3D-photodriven catalytic processes above the millimeter scale and up to a 6 mm thickness. A rather simple Langmuir-Hinshelwood based kinetic model is proposed which highlights the strong dependence of photocatalytic reaction rates on light scattering and the crucial role on oxidation back-reactions. In addition, a strong correlation between light attenuation coefficient and photon mean free path and median pore aperture diameter is demonstrated, offering thus a tool for photocatalytic behavior prediction.

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Section: Resultsmentioning

confidence: 55%

Bulk Photodriven CO₂ Conversion through TiO₂@Si(HIPE) Monolithic Macrocellular Foams

Bernadet

Tavernier

et al. 2019

Adv Funct Materials

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“…On the one hand, the fraction of solid surface for the superhydrophobic samples contacting with liquid is on the order of a few percent, thus decreasing the probability of hydrolysis and desorption. On the other hand, thermal treatment during laser texturing of the surface suppresses the hydrolytic activity of the Me–O–Si bond for the chemisorbed molecules. , …”

Section: Results and Discussionmentioning

confidence: 99%

Combination of Functional Nanoengineering and Nanosecond Laser Texturing for Design of Superhydrophobic Aluminum Alloy with Exceptional Mechanical and Chemical Properties

et al. 2017

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Industrial application of metallic materials is hindered by several shortcomings, such as proneness to corrosion, erosion under abrasive loads, damage due to poor cold resistance, or weak resistance to thermal shock stresses, etc. In this study, using the aluminum-magnesium alloy as an example of widely spread metallic materials, we show that a combination of functional nanoengineering and nanosecond laser texturing with the appropriate treatment regimes can be successfully used to transform a metal into a superhydrophobic material with exceptional mechanical and chemical properties. It is demonstrated that laser chemical processing of the surface may be simultaneously used to impart multimodal roughness and to modify the composition and physicochemical properties of a thick surface layer of the substrate itself. Such integration of topographical and physicochemical modification leads to specific surface nanostructures such as nanocavities filled with hydrophobic agent and hard oxynitride nanoinclusions. The combination of superhydrophobic state, nano- and micro features of the hierarchical surface, and the appropriate composition of the surface textured layer allowed us to provide the surface with the outstanding level of resistance of superhydrophobic coatings to external chemical and mechanical impacts. In particular, experimental data presented in this study indicate high resistance of the fabricated coatings to pitting corrosion, superheated water vapor, sand abrasive wear, and rapid temperature cycling from liquid nitrogen to room temperatures, without notable degradation of superhydrophobic performance.

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“…This allotropic phase transition is completely canceled when the P25 nanoparticles are embedded within the silica matrixes. This phenomenon is kind of unexpected because, during the liquid-phase hydrolysis in excess water, water molecules formed a thin film on the modified matrix surface and easily cleaved the Si–O–Ti bonds to afford discretized SiO 2 and TiO 2 phases . However, at the molecular level, we have already observed such a forbidden silica–titania interaction where TiO 2 was heterogeneously grown at the silica wall surface, and we mentioned “a pseudo epitaxial phenomenon demonstrating that···, the Si–O–Ti bonds at the silica/titania interfaces are not cleaved, as the amorphous silica network can hinder the TiO 2 crystallization upon thermal treatment, when no pre-hydrolyzed sols are employed”.…”

Section: Resultsmentioning

confidence: 94%

TiO₂–SiO₂ Self-Standing Materials bearing Hierarchical Porosity: MUB-200(x) Series toward 3D-Efficient VOC Photoabatement Properties

Layan

Gupta

et al. 2023

Langmuir

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Three-dimensional photoactive self-standing porous materials have been synthesized through the integration of soft chemistry and colloids (emulsions, lyotrope mesophases, and P25 titania nanoparticles). Final multiscale porous ceramics bear 700–1000 m2 g–1 of micromesoporosity depending on the P25 nanoparticle contents. The applied thermal treatment does not affect the P25 anatase/rutile allotropic phase ratio. Photonic investigations correlated with the foams’ morphologies suggest that the larger amount of TiO2 that is introduced, the larger the walls’ density and the smaller the mean size of the void macroscopic diameters, with both effects inducing a reduction of the photon transport mean free path (l t) with the P25 content increase. A light penetration depth in the range of 6 mm is reached, thus depicting real 3D photonic scavenger behavior. The 3D photocatalytic properties of the MUB-200(x) series, studied in a dynamic “flow-through” configuration, show that the highest photoactivity (concentration of acetone ablated and concentration of CO2 formed) is obtained with the highest monolith height (volume) while providing an average of 75% mineralization. These experimental results validate the fact that these materials, bearing 3D photoactivity, are paving the path for air purification operating with self-standing porous monolith-type materials, which are much easier to handle than powders. As such, the photocatalytic systems can now be advantageously miniaturized, thereby offering indoor air treatment within vehicles/homes while drastically limiting the associated encumbrance. This volumetric counterintuitive acting mode for light-induced reactions may find other relevant advanced applications for photoinduced water splitting, solar fuel, and dye-sensitized solar cells while both optimizing photon scavenging and opening the path for the miniaturization of the processes where encumbrance or a foot-print penalty would be advantageously circumvented.

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Hydrolytic stability of the Si–O–Ti bonds in the chemical assembly of titania nanostructures on silica surfaces

Cited by 10 publications

References 64 publications

Bulk Photodriven CO₂ Conversion through TiO₂@Si(HIPE) Monolithic Macrocellular Foams

Bulk Photodriven CO₂ Conversion through TiO₂@Si(HIPE) Monolithic Macrocellular Foams

Combination of Functional Nanoengineering and Nanosecond Laser Texturing for Design of Superhydrophobic Aluminum Alloy with Exceptional Mechanical and Chemical Properties

TiO₂–SiO₂ Self-Standing Materials bearing Hierarchical Porosity: MUB-200(x) Series toward 3D-Efficient VOC Photoabatement Properties

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Hydrolytic stability of the Si–O–Ti bonds in the chemical assembly of titania nanostructures on silica surfaces

Cited by 10 publications

References 64 publications

Bulk Photodriven CO2 Conversion through TiO2@Si(HIPE) Monolithic Macrocellular Foams

Bulk Photodriven CO2 Conversion through TiO2@Si(HIPE) Monolithic Macrocellular Foams

Combination of Functional Nanoengineering and Nanosecond Laser Texturing for Design of Superhydrophobic Aluminum Alloy with Exceptional Mechanical and Chemical Properties

TiO2–SiO2 Self-Standing Materials bearing Hierarchical Porosity: MUB-200(x) Series toward 3D-Efficient VOC Photoabatement Properties

Contact Info

Product

Resources

About

Bulk Photodriven CO₂ Conversion through TiO₂@Si(HIPE) Monolithic Macrocellular Foams

Bulk Photodriven CO₂ Conversion through TiO₂@Si(HIPE) Monolithic Macrocellular Foams

TiO₂–SiO₂ Self-Standing Materials bearing Hierarchical Porosity: MUB-200(x) Series toward 3D-Efficient VOC Photoabatement Properties