Layered Structures and Pillared Layered Structures

Cool, Pegie; Vansant, Etienne F.; Poncelet, Georges; Schoonheydt, Robert A.

doi:10.1002/9783527618286.ch20

Cited by 10 publications

(5 citation statements)

References 141 publications

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“…Another class of nanoporous materials are pillared structures, which exhibit both microand mesoporosities [66]. These materials are obtained by transforming an inorganic layered compound (mineral clays, metal oxide phosphate, layered double hydroxides etc) into a chemically and thermally stable porous material that keeps the layer structure.…”

Section: Introductionmentioning

confidence: 99%

“…This is done by introducing pillars between layers of the initial layered structure. This pillaring process involves several steps including swelling of the layered structure in a polar solvent, ion exchanges between the sample and the pillared agent and calcination of the sample [66]. Only materials with charged layers such as clays can be pillared (the solid must have cationic exchange capacity).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of confinement on freezing and melting

Alba‐Simionesco

Coasne

Dosseh

et al. 2006

J. Phys.: Condens. Matter

784

823

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We present a review of experimental, theoretical, and molecular simulation studies of confinement effects on freezing and melting. We consider both simple and more complex adsorbates that are confined in various environments (slit or cylindrical pores and also disordered porous materials). The most commonly used molecular simulation, theoretical and experimental methods are first presented. We also provide a brief description of the most widely used porous materials. The current state of knowledge on the effects of confinement on structure and freezing temperature, and the appearance of new surface-driven and confinement-driven phases are then discussed. We also address how confinement affects the glass transition.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of confinement on freezing and melting

Alba‐Simionesco

Coasne

Dosseh

et al. 2006

J. Phys.: Condens. Matter

784

823

View full text Add to dashboard Cite

show abstract

“…The development in the 1970s of inorganic pillared interlayered clays (in short PILCs), an important category of microporous materials, has created remarkable new opportunities in the field of the synthesis and applications of clay-based solids. − Materials with larger pore sizes and stronger acid properties than zeolites have been the object of this research. These materials are prepared by exchanging the charge-compensating cations present in the interlamellar space of the swelling smectitic clays with hydroxy−metal polycations.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Platinum Content on the Microstructure and Micropore Size Distribution of Pt/Alumina-Pillared Clays

et al. 2005

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The aim of this work is to study the effect of the platinum content (0-1.8 wt % Pt) on the microstructure of an alumina-pillared clay. For this purpose, the nitrogen physisorption data at -196 degrees C, the micropore size distributions of the supported platinum catalysts, and the hydrogen chemisorption results at 30 degrees C have been analyzed and compared. The preparation of the catalysts has modified the textural properties of the Al-pillared clay support, giving rise to a loss of surface area and micropore volume. After reduction at 420 degrees C, the presence of dispersed metallic platinum with mean crystallite size in the 22-55 A range has been found by hydrogen adsorption. Comparison of all results reveals that the platinum species block the micropore entrances by steric hindrance to nitrogen access as the platinum content increases.

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“…The process of pillaring of a layered material includes the following steps [6]: (i) swelling in a polar solvent (usually water); (ii) substitution of the original interlayer cations by bulky (inorganic/organic) cations (pillaring agent); (iii) washing (further chemical reactions occur at this step); (iv) calcination (pillars are formed) (Fig. 2).…”

Section: Introductionmentioning

confidence: 99%

Pillared Materials from Layer Titanosilicates?

Ferraris

2006

SSP

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Heterophyllosilicates are mineral phases based on layers that are comparable with those of the better known TOT phyllosilicates. Precisely, the HOH layers occurring in the heterophyllosilicates are formally obtained from a TOT layer by periodically introducing five or six co-ordinated titanium in the silicatic T sheets that sandwich the octahedral O sheet. The structural analogy between smectites, from which the mesoporous pillared clays are prepared, and heterophyllosilicates suggests that in principle pillared materials based on HOH layers could be prepared. Field observations show that swelling can occur in heterophyllosilicates; however, these minerals are rare and their synthetic analogues must first be prepared before attempting pillaring, an operation that might lead to interesting results for materials science owing to the presence of titanium.

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Layered Structures and Pillared Layered Structures

Cited by 10 publications

References 141 publications

Effects of confinement on freezing and melting

Effects of confinement on freezing and melting

Effect of the Platinum Content on the Microstructure and Micropore Size Distribution of Pt/Alumina-Pillared Clays

Pillared Materials from Layer Titanosilicates?

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