In situ IR spectroscopic study to reveal the impact of the synthesis conditions of zeolite β nanoparticles on the acidic properties of the resulting zeolite

Oers, Cynthia J. Van; Góra‐Marek, Kinga; Sadowska, K.; Mertens, Myrjam; Meynen, Vera; Dátka, Jerzy; Cool, Pegie

doi:10.1016/j.cej.2013.10.041

Cited by 41 publications

(22 citation statements)

References 49 publications

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“…37 An attenuation with the Si/Al ratio and the temperature was observed for the desorption peak (1,480 cm À1 ) in the NH 3 -IR spectra (Figure S20), revealing a decline of Brønsted acid sites. 41 This was further confirmed by the 1 H MAS NMR spectral result that the peak (at 3.9 ppm) assigned to bridging hydroxyl groups (Si(OH)Al) in framework 42 showed a lower intensity at a higher Si/Al ratio (Figure S19D). Detection of negligible amounts of acid sites by Py-IR (Figure S19C; Table S6) indicated that almost all the acid sites were located in the internal surface, as these acid sites were inaccessible to pyridine molecules.…”

Section: Catalyst Characterizationmentioning

confidence: 53%

Selective Conversion of CO2 into Propene and Butene

Wang

Zhang

et al. 2020

Chem

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Section: Catalyst Characterizationmentioning

confidence: 53%

Selective Conversion of CO2 into Propene and Butene

Wang

Zhang

et al. 2020

Chem

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“…65% of Al is engaged in the formation of the Si(OH)Al groups; the rest of Al exists as the electron acceptor extraframework species [32,44]. However, this proportion decreases to 40% in the NaOH treated zeolite Beta, while is fully preserved (or even slightly increased) in the NaOH&TBAOH modified zeolite.…”

Section: Desilication Of Zeolite Resulted In the Increase Of Concentrmentioning

confidence: 92%

Catalytic cracking performance of alkaline-treated zeolite Beta in the terms of acid sites properties and their accessibility

Tarach

Góra‐Marek

Tekla

et al. 2014

Journal of Catalysis

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161

111

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The zeolite Beta is considered as a promising additive for FCC catalyst in diesel oil production. In this article, it is shown that hierarchical zeolite Beta obtained by an optimized desilication procedure increases Diesel and propylene yields during gas-oil cracking reaction.The alkaline treatment of zeolite Beta (Si/Al = 22) by desilication with NaOH and NaOH&TBAOH was investigated. The catalytic performance improvement of desilicated zeolite Beta has been rationalized by deep characterization of the samples including X-ray diffraction, low temperature adsorption of nitrogen, solid-state 29 Si MAS NMR and IR studies of acidity. Finally, the catalytic performance of the zeolites Beta was evaluated in the cracking of n-decane, 1,3,5-tri-iso-propylbenzene and vacuum gas oil. It was found that desilication with NaOH&TBAOH ensures the more uniform intracrystalline mesoporosity with the formation of narrower mesopores, while preserving full crystallinity resulting in catalysts with the most appropriated acidity and then, with better catalytic performance.

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“…The extinction coefficient of 0.026 cm 2 mmol À1 for the NH 3 L band was determined in experiments in which ammonia was adsorbed in dehydroxylated zeolite HY (pre-treated at 1070 K), containing Lewis acid sites as main species. 25 Even if the 1620 cm À1 band could be due to ammonia interacting with Lewis sites of different nature, i.e. Al-(in dehydroxylated zeolite HY) or Co-Lewis ones (in zeolite under the study), the same value of the extinction coefficient was assumed based on the same value of the NH 3 -Co and NH 3 -Al band frequencies.…”

Section: Methodsmentioning

confidence: 99%

Ammonia-modified Co(ii) sites in zeolites: IR spectroscopy and spin-resolved charge transfer analysis of NO adsorption complexes

Góra‐Marek

Stępniewski

Radoń

et al. 2014

Phys. Chem. Chem. Phys.

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IR spectroscopic studies and quantum chemical modeling (aided by the analysis of charge transfer processes between co-adsorbed ammonia and the Co(II)-NO adduct) evidence that donor ammonia molecules, ligated to extraframework Co(2+) centers in zeolites, vitally affect the strength of the N-O bond. Calculations indicate that versatility of ammine nitrosyl complexes, differing in the number of NH3 ligands as well as in the geometry and electronic structure of the Co-N-O unit (showing variable activation of NO) may co-exist in zeolite frameworks. However, only combined analysis of experimental and calculation results points to the adducts with three or five NH3 coligands as decisive. The novel finding concerning the interpretation of discussed IR spectra is the assignment of the most down-shifted bands at 1600-1615 cm(-1) to the N-O stretch in the singlet [Co(NH3)3(NO)](2+) adduct, in place of tentative ascription to pentaammine adducts. Theory indicates also that the Co(ii) center (with manifold of close-lying electronic and spin states) acts as a tunable electron donor where the spin state may open or close specific channels transferring electron density from the donor ligands (treated as the part of environment) to the NO molecule.

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In situ IR spectroscopic study to reveal the impact of the synthesis conditions of zeolite β nanoparticles on the acidic properties of the resulting zeolite

Cited by 41 publications

References 49 publications

Selective Conversion of CO2 into Propene and Butene

Selective Conversion of CO2 into Propene and Butene

Catalytic cracking performance of alkaline-treated zeolite Beta in the terms of acid sites properties and their accessibility

Ammonia-modified Co(ii) sites in zeolites: IR spectroscopy and spin-resolved charge transfer analysis of NO adsorption complexes

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