New Insight into the Synthesis of Large-Pore Ordered Mesoporous Materials

Rationally Turning the Interface Activity of Mesoporous Silicas for Preparing Pickering Foam and "Dry Water"

We develop a novel protocol to prepare smart, gas/water interface-active, mesoporous silica particles. This protocol involves modification of highly mesoporous silicas with a mixture of hydrophobic octyl organosilane and hydrophilic triamine organosilane. Their structure and compositions are characterized by transmission electron microscopy (TEM), N₂ sorption, solid state NMR, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FT-IR), thermogravimetric analysis (TGA), and elemental analysis. It is demonstrated that our protocol enables the interface activity of mesoporous silica particles to be facilely tuned, so that the stable gas-water interfaces ranging from air bubbles dispersed in water (Pickering foam) and water droplets dispersed in air ("dry water") can be achieved, depending on the molar ratio of these two organosilanes. The "dry water" is not otherwise attainable for the analogous nonporous silica particles, indicting the uniqueness of the chosen mesoporous structures. Moreover, these particle-stabilized Pickering foams and "dry waters" can be disassembled in response to pH. Interestingly, it was found that aqueous potassium carbonate droplets stabilized by these interface-active mesoporous silica particles ("dry K₂CO₃-containing water") could automatically capture CO₂ from a simulated flue gas with enhanced adsorption rate and adsorption capacity when compared to the aqueous potassium carbonate bulk solution. This study not only supplies a novel type of efficient, smart, gas/water interface-active mesoporous silica particles but also demonstrates an innovative application of mesoporous materials in gas adsorption.

Structure identification of Ti(iv) clusters in low-temperature TiO2 crystallization: creating high-surface area brush-shaped rutile TiO2

We demonstrate for the first time a controlled reaction of Cl-coordinating Ti(iv) clusters in low-temperature hydrolysis (27 °C) to create large-surface area rutile TiO₂ crystals.