Open AccessComparison of Nitrogen Adsorption and Mercury Penetration Results. Pore Size Distributions for a Series of Mo-A12O3 Catalysis with Increasing MoO3 Content
Author(s) -
Bruce D. Adkins,
Jill B. Heink,
Burtron H. Davis
Publication year - 1987
Publication title -
adsorption science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.682
H-Index - 36
eISSN - 2048-4038
pISSN - 0263-6174
DOI - 10.1177/0263617487004001-208
Subject(s) - penetration (warfare) , mercury (programming language) , chemistry , adsorption , porosity , monolayer , nitrogen , specific surface area , scanning electron microscope , catalysis , analytical chemistry (journal) , composite material , chromatography , materials science , organic chemistry , operations research , computer science , engineering , programming language , biochemistry
Scanning electron microscopic data, X-ray diffraction patterns and porosity measurements are consistent with a structure for an Mo-A1 2 O 3 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 MoO 3 is also present. The cumulative pore volume, on an alumina basis, does not appear to be significantly altered by MoO 3 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.