Characterization of pillared montmorillonites with the atomic force microscope (AFM)

Journal Article · Sun Aug 01 00:00:00 EDT 1993 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1993.1212· OSTI ID:5605995

Occelli, M L ^[1]; Drake, B ^[2]; Gould, S A.C. ^[3]

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1. Georgia Tech Research Institute, Atlanta, GA (United States)
2. Imaging Services, Santa Barbara, CA (United States)
3. Claremont College, CA (United States)

An atomic force microscope (AFM) has been used to investigate the surface features of samples of Ca-bentonite from Texas and Na-bentonite from Wyoming that were pillared with alumina clusters. Atomic-scale-resolution images of the clay surface consist of hexagonal arrays of bright spots. The nearest-neighbor distance in the two parent clays was found to be consistently greater after pillaring in numerous images, suggesting that the bulky Al[sub 13] clusters stretched the clays' silicate layers. A number of images showed possible atomic resolution of oxygen atoms on the clay surface, suggesting that it can be possible to obtain resolution below the scale of the unit cell. Molecular-scale-resolution images of the cross-sectional area of extrudates formed using pillared Wyoming bentonite powder showed platelets about 9.0 [angstrom] apart, in agreement with X-ray diffraction (XRD) results. The presence of alumina debris or clusters on the silicate layer was not observed in any image examined, suggesting that the expended clay coking tendency during gas oil cracking can be attributed mainly to the strong Lewis-type acidity of the alumina pillars between the clay silicate layers. 29 refs., 10 figs., 1 tab.

• OSTI ID: 5605995
• Journal Information: Journal of Catalysis; (United States), Vol. 142:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
02 PETROLEUM
BENTONITE
STRUCTURAL CHEMICAL ANALYSIS
ALUMINIUM OXIDES
COKING
CRACKING
LEWIS ACIDS
MICROSCOPY
MONTMORILLONITE
SURFACE PROPERTIES
ALUMINIUM COMPOUNDS
CARBONIZATION
CHALCOGENIDES
CHEMICAL REACTIONS
CLAYS
DECOMPOSITION
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
OXIDES
OXYGEN COMPOUNDS
PYROLYSIS
THERMOCHEMICAL PROCESSES
360602* - Other Materials- Structure & Phase Studies
020400 - Petroleum- Processing