Characterization of Unmodified and Zinc-modified ZSM-5 Zeolites with Temperature-programmed Desorption of Ammonia and Isopropylamine

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Authors

Date

2025-12

Department

Department of Chemical and Metallurgical Engineering

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Mcode

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Language

en

Pages

11

Series

Topics in Catalysis, Volume 68, issue 20, pp. 2393-2403

Abstract

While the temperature-programmed desorption of ammonia (NH3-TPD) is widely used to analyze the combined Lewis and Brønsted acidity of heterogeneous catalysts, the temperature-programmed desorption of isopropylamine (IPAm-TPD) can be used for the selective analysis of Brønsted acidity. This work compared NH3-TPD and IPAm-TPD as analysis methods for the acidity of zeolitic samples, including H-ZSM-5-23, H-ZSM-5-50, H-ZSM-5-280, a Zn-modified H-ZSM-5-50 sample, and a γ-Al2O3 reference sample. For the unmodified H-ZSM-5-23, H-ZSM-5-50, and H-ZSM-5-280, the total acidity determined with NH3-TPD remained higher and the Brønsted acidity determined with IPAm-TPD lower than the theoretical acidity estimated with the Al content of the materials. When the NH3-TPD saturation temperature was varied for H-ZSM-5-50 to examine the trends observed in the analyses, the temperature change affected primarily the low temperature peak of the TPD traces. The Zn-modified Zn/H-ZSM-5-50 sample yielded a multi-peak IPAm-TPD trace, though only a single peak trace was expected. Additionally, the value of Brønsted acidity showed no change from the unmodified zeolite.

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Publisher Copyright: © The Author(s) 2025.

Keywords

Acidity, H-ZSM-5, IPAm-TPD, NH-TPD

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DOI

10.1007/s11244-025-02112-0

Citation

Järvinen, E, Velasco, J A, Karinen, R & Puurunen, R L 2025, 'Characterization of Unmodified and Zinc-modified ZSM-5 Zeolites with Temperature-programmed Desorption of Ammonia and Isopropylamine', Topics in Catalysis, vol. 68, no. 20, pp. 2393-2403. https://doi.org/10.1007/s11244-025-02112-0

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https://urn.fi/URN:NBN:fi:aalto-202601051073

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[article-cris] Kemian tekniikan korkeakoulu / CHEM