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Understanding the AC conductivity and permittivity of trapdoor chabazites for future development of next-generation gas sensors

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)208-216
Number of pages9
JournalMicroporous and Mesoporous Materials
Volume260
Early online date26 Oct 2017
DOIs
DateIn preparation - Feb 2017
DateAccepted/In press - 22 Oct 2017
DateE-pub ahead of print - 26 Oct 2017
DatePublished (current) - 1 Apr 2018

Abstract

Synthetic K+ chabazite (KCHA), Cs+ chabazite (CsCHA) and Zn2+ chabazite (ZnCHA) have been synthesized and investigated in order to relate the differences in their crystalline structures to their thermal stability, moisture content and frequency dependent alternating current (AC) conductivity, permittivity and phase angle at a range of temperatures. The materials are shown to exhibit the universal dielectric response, which is typical of materials consisting of both conductive and insulating regions. Due to the presence of porosity, the three chabazites were hydrated significantly at room temperature and so the dehydrated state was achieved by heating the chabazites to high temperatures to ensure that all different energetic types of water were removed. Cation migration activation energies for KCHA (0.66 ± 0.10) eV, CsCHA (0.88 ± 0.01) eV and ZnCHA (0.90 ± 0.01) eV were determined during the cooling cycle from the fully dehydrated state to provide an accurate measurement of the activation energies. Good thermal stability of the materials was observed up to 710 °C and below 200 °C the electrical properties can be strongly influenced by hydration level. Overall, it was determined that when either hydrated or dehydrated, KCHA had the highest conductivity and lowest cation migration activation energy of the three studied chabazites and thus has the most promising electrical properties for potential use as a gas sensing material in next-generation electrical-based gas sensors.

    Research areas

  • Chabazites, Conductivity, Permittivity, Trapdoor, Zeolites

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  • Full-text PDF (accepted author manuscript)

    Rights statement: This is the author accepted manuscript (AAM). The final published version (version of record) is available online via Elsevier at http://www.sciencedirect.com/science/article/pii/S138718111730687X. Please refer to any applicable terms of use of the publisher.

    Accepted author manuscript, 11 MB, PDF-document

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