Element distribution and growth mechanism of large SAPO-5 crystals

Schunk, Stephan A.; Demuth, Dirk; Schulz-Dobrick, B.; Unger, K. K.; Schüth, Ferdi

doi:10.1016/0927-6513(96)00011-9

Cited by 33 publications

(21 citation statements)

References 20 publications

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“…The origin of the intergrowth effects may be derived from the progress of the crystal growth. As has been shown in (Schunk et al, 1996) a2,a3) and b2,b3) crystals integrated along the y direction under equilibrium with water vapor at 1 mbar (a1, b1, a3, b3) and 20 mbar (a2, b2). The profiles under the pressure of 1 mbar were recorded after change of the water pressure form 0 to 1 mbar (a1, b1) and from 20 to 1 mbar (a3, b3).…”

Section: Resultsmentioning

confidence: 81%

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Internal Transport Resistances and their Influence on Diffusion in Zeolites as Traced by Microscopic Measuring Techniques

et al. 2005

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Interference microscopy (IFM) and FTIR microscopy (IRM) are applied to study intracrystalline concentration profiles in SAPO-5, CrAPO-5 and ZSM-5 zeolite crystals. By using both techniques, the high spatial resolution of interference microscopy is complemented by the ability of FTIR spectroscopy to pinpoint adsorbates by their characteristic IR bands. In this way the experimental results are shown to unveil a number of remarkable deviations in the real structure of zeolite crystals from their textbook patterns. The influence of structural defects on the equilibrium concentration profiles as well as on sorption dynamics of guest molecules is investigated. Owing to the ability to gain direct insight into the influence of surface defects and intracrystalline defects on molecular uptake, the applied techniques give more accurate information on the molecular transport in zeolite crystals than the classical uptake methods.

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Section: Resultsmentioning

confidence: 81%

“…The samples of SAPO-5 and CrAPO-5 were prepared and calcined as described in Kornatowski et al (2001), Padlyak et al (2000), Schüth et al (1994); Schunk et al (1996). The chromium content of CrAPO-5 was 0.25 Cr per u.c.. Methanol and water were used as guest molecules for CrAPO-5 and SAPO-5.…”

Section: Methodsmentioning

confidence: 99%

Internal Transport Resistances and their Influence on Diffusion in Zeolites as Traced by Microscopic Measuring Techniques

et al. 2005

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“…[24] Secondly, several characterization studies confirmed that the use of Si 4+ and Cr 3+ during synthesis inhibits crystal growth along the c direction and thus results in low aspect ratios. [25][26][27] Our observations suggest that while certain metal ions affect the crystallization kinetics by inhibiting crystal growth rate along the c direction, other metal ions, such as Mo 6+ , induce the opposite effect by promoting crystal growth in the c direction and forming very elongated crystals.…”

Section: Angewandte Chemiementioning

confidence: 98%

Unified Internal Architecture and Surface Barriers for Molecular Diffusion of Microporous Crystalline Aluminophosphates

et al. 2010

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Starless molecular sieves: The starlike appearence of confocal fluorescence microscopy (CFM) images of large crystals of the AlPO‐5 family of microporous materials is due to the presence of barriers to molecular diffusion in the internal crystal architecture (see picture) rather than a star‐shaped subcrystal according to studies by CFM, focused ion beam milling, electron backscatter diffraction, and atomic force microscopy.

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“…Single crystals with nearly perfect morphology were grown using hydrofluoric acid [15]. With a specially prepared and aged aluminum hydroxide gel crystal sizes around 1 mm in caxis direction were obtained [16], whereas microwave heating proved to increase the crystallization rates by more than one order of magnitude [15,17].…”

Section: Host Crystalmentioning

confidence: 99%

Hexagonal microlasers based on organic dyes in nanoporous crystals

Braun

Ihlein

Laeri

et al. 2000

Applied Physics B: Lasers and Optics

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137

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Molecular sieves, such as nanoporous AlPO4-5, can host a wide variety of laser active dyes. We embedded pyridine 2 molecules as a representative of a commercially available dye which fits into the channel pores of the host matrix. Many efficient dye molecules, such as rhodamines, do not fit into the pores. But modifying the structure of the dyes to appear like the used templates allows to increase the amount of encapsulated dyes. The properties of resulting microlasers depend on size and shape of the microresonators, and we discuss a model for microscopic hexagonal ring resonators. In terms of pump needed to reach lasing threshold molecular sieve microlasers are comparable to VCSELs. For dyes which fit into the pores we observed a partial regeneration of photo-induced damage.

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Element distribution and growth mechanism of large SAPO-5 crystals

Cited by 33 publications

References 20 publications

Internal Transport Resistances and their Influence on Diffusion in Zeolites as Traced by Microscopic Measuring Techniques

Internal Transport Resistances and their Influence on Diffusion in Zeolites as Traced by Microscopic Measuring Techniques

Unified Internal Architecture and Surface Barriers for Molecular Diffusion of Microporous Crystalline Aluminophosphates

Hexagonal microlasers based on organic dyes in nanoporous crystals

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