Effect of Rate of Nitrogen Adsorption and Desorption on the Automated Determination of Pore Size Distributions.

TiO2mesoporous microspheres self-assembled from nanoparticles were synthesized by a surfactant-free solvothermal route. The TiO2precursors were fabricated by tetrabutyl titanate, glacial acetic acid, and urea in the ethanol solution at 140°C for 20 h, and TiO2mesoporous microspheres were obtained by a postcalcination at temperatures of 450°C for promoting TiO2crystallization and the removal of residual organics. The phase structure, morphology, and pore nature were characterized by XRD, SEM, and nitrogen adsorption-desorption measurements. The as-prepared TiO2microspheres are in anatase phase, with 2-3 μm in diameter, and narrow pore distribution range is 3-4 nm. The adjustments of the synthetic parameters lead to the formation of the mesoporous TiO2microspheres with tuned pore size distributions and morphology.

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Comparison of Nitrogen Adsorption and Mercury Penetration Results. Pore Size Distributions for a Series of Mo-A12O3 Catalysis with Increasing MoO3 Content

Adsorption Science & Technology ◽

10.1177/0263617487004001-208 ◽

1987 ◽

Vol 4 (1-2) ◽

pp. 87-104 ◽

Cited By ~ 3

Author(s):

Bruce D Adkins ◽

Jill B. Heink ◽

Burtron H. Davis

Keyword(s):

Pore Size ◽

Surface Area ◽

Three Dimensional ◽

Nitrogen Adsorption ◽

Bet Surface Area ◽

Size Distributions ◽

Electron Microscopic ◽

Pore Size Distributions ◽

Electron Microscopic Data ◽

Penetration Data

Scanning electron microscopic data, X-ray diffraction patterns and porosity measurements are consistent with a structure for an Mo-A12O3 catalyst series containing a single surface layer of Mo up to the point where the Mo loadings exceed the amount required for a monolayer. For greater Mo loadings than required for a monolayer, three dimensional orthorhombic MoO3 is also present. The cumulative pore volume, on an alumina basis, does not appear to be significantly altered by MoO3 loadings up to about 15 wt.%. The BET surface area, on an alumina basis, remains constant with Mo loading. However, the apparent surface area calculated from mercury penetration data decreases with Mo loading. For these materials with cylindrical pores, the Broekhoff-deBoer model for the calculation of pore size distributions produced closer agreement to the mercury penetration pore size distribution. This is in contrast to materials composed of nonporous spheres where the Broekhoff-deBoer model provided poorer agreement to mercury penetration results than either the Cohan or a packed sphere model. The results show that, within a factor of two the pore size distributions calculated from nitrogen adsorption and mercury penetration data are comparable.

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Determination of Pore Size Distributions in Nano-Porous Thin Films from Small Angle Scattering

MRS Proceedings ◽

10.1557/proc-766-e8.9 ◽

2003 ◽

Vol 766 ◽

Author(s):

Barry J. Bauer ◽

Ronald C. Hedden ◽

Hae-Jeong Lee ◽

Christopher L. Soles ◽

Da-Wei Liu

Keyword(s):

Pore Size ◽

Small Angle ◽

Length Distribution ◽

Dielectric Constants ◽

Scattering Data ◽

Size Distributions ◽

Average Pore ◽

Pore Size Distributions ◽

Phase Size

AbstractSmall angle neutron and x-ray scattering (SANS, SAXS) are powerful tools in determination of the pore size and content of nano-porous materials with low dielectric constants (low-k) that are being developed as interlevel dielectrics. Several models have been previously applied to fit the scattering data in order to extract information on the average pore and/or matrix size. A new method has been developed to provide information on the size distributions of the pore and matrix phases based on the “chord length distribution” introduced by Tchoubar and Mering. Examples are given of scattering from samples that have size distributions that are narrower and broader than the random distribution typical of scattering described by Debye, Anderson, and Brumberger. An example of fitting SANS data to a phase size distribution is given.

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Determination of pore size distributions of liquid chromatographic column packings by gel permeation chromatography

Analytical Chemistry ◽

10.1021/ac00270a021 ◽

1984 ◽

Vol 56 (6) ◽

pp. 950-957 ◽

Cited By ~ 37

Author(s):

F. Vincent. Warren ◽

Brian A. Bidlingmeyer

Keyword(s):

Pore Size ◽

Gel Permeation Chromatography ◽

Chromatographic Column ◽

Size Distributions ◽

Pore Size Distributions ◽

Gel Permeation ◽

Liquid Chromatographic ◽

Column Packings

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Article

Canadian Journal of Chemistry ◽

10.1139/v98-025 ◽

1998 ◽

Vol 76 (4) ◽

pp. 382-388 ◽

Cited By ~ 1

Author(s):

Jack M Miller ◽

David Wails ◽

J Stephen Hartman ◽

Karla Schebesh ◽

Jennifer L Belelie

Keyword(s):

Catalytic Activity ◽

Pore Size ◽

Zinc Chloride ◽

Sol Gel ◽

Nitrogen Adsorption ◽

Potassium Fluoride ◽

Physical Structure ◽

Alkylation Reaction ◽

Size Distributions ◽

Pore Size Distributions

Novel mesoporous silicas have been prepared via a sol-gel route involving fluoride-catalyzed hydrolysis of tetraethylorthosilicate (TEOS). Incorporation of zinc chloride by sol-gel synthesis gives a range of mesoporous materials with significantly higher catalytic activity than the commercially available catalyst, Clayzic, in a model Friedel-Crafts alkylation reaction. The dependence of catalytic activity and physical structure on the amounts of solvent, water, zinc chloride, and potassium fluoride used in the preparation are explored, and the materials have been further characterized by nitrogen adsorption to determine surface areas, total pore volumes, and pore-size distributions and by 29Si and 19F MAS NMR spectroscopy. The most active catalysts generally have the highest total pore volumes, with pore-size distributions larger than 8 nm.Key words: sol-gel, Friedel-Crafts, Clayzic, silica.

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