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| - X-ray Structural Modeling and Gas Adsorption Analysis of CagelikeSBA-16 Silica Mesophases Prepared in a F127/Butanol/H2O System
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| - A detailed characterization of large-pore cagelike mesoporous SBA-16 silica materials with tailoredpore dimensions is reported. The materials were synthesized in a EO106PO70EO106 (F127)−butanol−H2Osystem under mildly acidic conditions, and the pore diameters were tailored by varying the hydrothermaltreatment temperature. Structural information was acquired by full-profile analysis of powder X-raydiffraction (XRD) patterns. High-resolution diffraction data were obtained for all the materials usingsynchrotron radiation as the X-ray source, enabling a comprehensive XRD modeling supplemented withthe generation of electron density distribution maps. The structural parameters derived from the XRDmodeling were compared with data obtained from nitrogen and argon physisorption experiments performedat −196 °C. An excellent agreement was found between the XRD modeling results and those obtainedby a new nonlocal density functional theory (NLDFT) kernel developed for pore size analysis based ongas adsorption in spherical pores, while NLDFT analysis based on a cylindrical pore model was shownto systematically underestimate the pore dimensions by about 30% which exceeds previous expectations.Furthermore, the Barrett−Joyner−Halenda model was shown to give errors up to about 45% in the poresize range above 4 nm. The structure of the surfactant−silica hybrid materials was also analyzed byXRD, which shed more light on the structural changes accompanying the thermal surfactant removalprocess. The present study is expected to provide a reference source for the accurate characterization oflarge cagelike mesoporous silica materials, on the basis of a direct comparison of suitable data collectedindependently by gas physisorption and comprehensive XRD modeling.
- A detailed characterization of large-pore cagelike mesoporous SBA-16 silica materials with tailored pore dimensions is reported. An excellent agreement was found between the XRD modeling results and data obtained by nonlocal density functional theory (NLDFT) kernel developed for pore size analysis based on gas adsorption in spherical pores.
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