New Evidence for Precursor Species in the Formation of MFI Zeolite in the Tetrapropylammonium Hydroxide−Tetraethyl Orthosilicate−Water System

Kirschhock, Christine; Kremer, Sebastien; Grobet, Piet J.; Jacobs, Pierre; Martens, Johan A.

doi:10.1021/jp015617x

Cited by 79 publications

(116 citation statements)

References 13 publications

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“…It has been well known that the organic species in the synthesis gels (such as TPA + ) serve as 'structure directors' for creation of nanopores in certain shapes, sizes, and networks in zeolites and the related molecular sieves [37,38]. Based on our results we also propose that the organic species incorporated within the synthesis gels can also play the role of 'orientation directors' for the resulting crystals by formation of supramolecularly organized organic-inorganic composites.…”

Section: Pdi/bdo Matrix Pdi/tbe Matrixsupporting

confidence: 64%

“…Dilution of the gel (7:6.6:3300) was detrimental to the formation of multi-crystal arrays, indicating that the gel should be dense and viscous. Based on the above results, and by taking into account the finding of Martens and coworkers that the synthesis gel readily produces TPA + -incorporating nanoslabs (seeds) during a few hours of aging even at room temperature [37,38], we propose that the following series of events occur sequentially.…”

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confidence: 62%

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Synthesis of Zeolite as Ordered Multi-Crystal Arrays using Uniformly Aligned Polyurethane as Templates

Lee

Tae

et al. 2004

MRS Proc.

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Two types of glass plates coated with uniformly aligned polyurethane films were produced by repeating the cycles of the alternative exposures of the glass plates to 1,4-phenylene diisocyanate (PDI) and 2-butyne-1,4-diol (BDO) and to PDI and terephthalic acid bis-(2-hydroxy ethyl) ester (TBE) for 500 times at elevated temperatures. The glass plates coated with uniformly aligned poly-(PDI-BDO) 500 (500 represents the number of the cycle) produced monolayers of closely packed 2D arrays of silicalite-1 crystals with the average size of 370 × 200 × 500 nm on the glass plates upon immersion of the glass plates into a dense gel consisting of tetraethylorthosilicate (TEOS), tetrapropylammonium hydroxide (TPA + OH − ), and water (mole ratio = 7:1.5:330) followed by the hydrothermal reaction at 180 °C for 2 h. The silicalite-1 crystals were aligned with the c-axes perpendicular to the substrate plane. Upon switching the polymer from poly-(PDI-BDO) 500 to poly-(PDI-TBE) 500 the orientations of the silicalite-1 crystals in the 2D arrays changed from c to a axes perpendicular to the substrate. This report therefore demonstrates that the uniformly aligned polyurethane films serve as the templates for the growth of closely packed multi-crystal arrays of silicalite-1 in uniform orientations and the nature of the polyurethane film affects the resulting orientations of the crystals. We propose that the supramolecularly organized organic-inorganic composites consisting of the hydrolyzed organic products and the seed crystals responsible for the above phenomena.

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Section: Pdi/bdo Matrix Pdi/tbe Matrixsupporting

confidence: 64%

mentioning

confidence: 62%

Synthesis of Zeolite as Ordered Multi-Crystal Arrays using Uniformly Aligned Polyurethane as Templates

Lee

Tae

et al. 2004

MRS Proc.

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“…Fe-ZSM-5, X zeolite) have been successfully synthesized and used in chemical processes [31,35], understanding the formation mechanism of zeolite is still all-important for the rational design and synthesis of new zeolites. Several assembly mechanisms have been proposed by scientists since the 1960s [45], including the growth from soluble and pre-assembled units [46][47][48], the autocatalytic nucleation [49,50] and solidliquid interfacial nucleation mechanism [51,52] etc. However, it's very difficult to study the detailed formation mechanism of zeolite due to the extreme complexity of hydrothermal crystallization [51].…”

Section: Uv Raman Spectroscopic Study On the Synthesis Mechanism Of Zmentioning

confidence: 99%

UV Raman Spectroscopic Characterization of Catalysts and Catalytic Active Sites

et al. 2014

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UV Raman spectroscopy has been demonstrated to be a powerful technique in catalysis because it can avoid the fluorescence interference occurring in visible Raman spectroscopy and concurrently enhance the Raman scattering intensity owing to the short wavelength of the excitation laser and resonance Raman effect. This article briefly reviews the recent advances in the study on heterogeneous catalysis by UV Raman spectroscopy, including the identification of isolated transition metal ions in molecular sieves, in situ study of zeolite assembly mechanisms and catalytic reaction mechanisms, and the monitoring of the surface phase transformation of metal oxide photocatalysts. UV (resonance) Raman spectroscopy, with the power of resonance enhancement for Raman signal and the advantage of high sensitivity for surface structure, coupling with in situ methodology, can provide the information about the active sites/phase and their assembling mechanisms, which are helpful for the understanding of heterogeneous catalysis and the rational design of highly active and selective catalysts.

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“…This framework structure has been understood as the combination of ringed silicate building blocks, [1][2][3] and some of the corresponding silicate oligomers have been detected and/or isolated. [4,5] Therefore molecular engineering can be used to design zeolite frameworks by assembling block oligomers or appropriate precursors which dehydration-condensation. However, there has been no example for this kind of molecular manipulation in zeolite synthesis so far, although some syntheses were carried out with this intent.…”

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confidence: 99%

The Topotactic Conversion of a Novel Layered Silicate into a New Framework Zeolite

Akiyama²,

et al. 2004

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Zeolites have been widely used, among others, as catalysts, ion exchangers, detergents, and adsorbents, and their range of applications continues to grow. Thus, there is a large demand for new types of zeolites with high thermal and chemical stability. However, new zeolites are still mainly synthesized by trial and error, and molecular engineering in their synthesis has been underdeveloped. Here we report that a thermostable zeolite with a novel framework is obtained by molecular manipulation, that is, topotactic dehydration-

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New Evidence for Precursor Species in the Formation of MFI Zeolite in the Tetrapropylammonium Hydroxide−Tetraethyl Orthosilicate−Water System

Cited by 79 publications

References 13 publications

Synthesis of Zeolite as Ordered Multi-Crystal Arrays using Uniformly Aligned Polyurethane as Templates

Synthesis of Zeolite as Ordered Multi-Crystal Arrays using Uniformly Aligned Polyurethane as Templates

UV Raman Spectroscopic Characterization of Catalysts and Catalytic Active Sites

The Topotactic Conversion of a Novel Layered Silicate into a New Framework Zeolite

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