Pillared-clay catalysts containing mixed-metal complexes I. Preparation and characterization

Journal Article · Sun Jan 01 00:00:00 EST 1989 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(89)90016-X· OSTI ID:7121560

Lee, W Y; Tatarchuk, B J ^[1]; Raythatha, R H ^[2]

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1. Auburn Univ., AL (USA)
2. ECC-America, Sandersville, GA (USA)

High-surface-area pillared clays were prepared from naturally occurring montmorillonites by exchanging interlayer ions with polyoxocations containing (i) iron, (ii) aluminum, (iii) discrete mixtures of (i) and (ii), or (iv) iron and aluminum located within the same complex. The valence state, solid-state properties, and stability of these pillars were determined following reduction and oxidation using Moessbauer spectroscopy, X-ray diffraction, and BET surface area measurements. Controlled atmosphere electron microscopy and transmission electron microscopy were also used to follow the nucleation and sintering behavior of the pillars during reduction. Moessbauer data suggested interlayer formation of metallic iron domains following reduction of types (i) and (iii) pillared systems. The magnetic properties and the oxidation behavior deduced from Moessbauer analysis and the complementary insights provided by XRD strongly indicated that these crystallites were in the form of thin-film/pancake-shape islands most likely conforming to the geometry of the interlayer region. The expanded structures of types (ii) and (iii) pillared systems were found to be relatively stable following reduction up to 723 K due to the irreducible nature of discrete aluminum pillars under these conditions. Intercalation of clays with mixtures of chemically distinct pillars appears to provide a unique method for preparing highly dispersed metallic or even bimetallic catalysts possessing two-dimensional sieve-like behavior with high overall surface areas and high loadings of the active metal.

• OSTI ID: 7121560
• Journal Information: Journal of Catalysis; (USA), Vol. 115:1; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CATALYSTS
CHEMICAL PREPARATION
MONTMORILLONITE
CHEMICAL PROPERTIES
MICROSTRUCTURE
ADDITIVES
ALUMINIUM
CLAYS
ELECTRON MICROSCOPY
ION EXCHANGE
IRON
LAYERS
MAGNETIC PROPERTIES
MOESSBAUER EFFECT
OXIDATION
PLATINUM
REDUCTION
SHAPE
SINTERING
SPECTROSCOPY
STABILITY
SURFACE AREA
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
X-RAY DIFFRACTION
CHEMICAL REACTIONS
COHERENT SCATTERING
CRYSTAL STRUCTURE
DIFFRACTION
ELEMENTS
FABRICATION
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
METALS
MICROSCOPY
PHYSICAL PROPERTIES
PLATINUM METALS
SCATTERING
SYNTHESIS
TRANSITION ELEMENTS
400201* - Chemical & Physicochemical Properties