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Schönauer-Kamin, Daniela ; Marr, Isabella ; Zehentbauer, Melanie ; Zängle, Clara ; Moos, Ralf:
Characterization of the sensitive material for a resistive NOₓ gas dosimeter by DRIFT spectroscopy.
In: Sensors and Actuators B: Chemical.
Bd. 320
(2020)
.
- 128568.
ISSN 0925-4005
DOI: https://doi.org/10.1016/j.snb.2020.128568
Abstract
Resistive NOx gas dosimeters measure continuously the integrated NOx concentration, i.e., the NOx dose. The impedance of potassium-manganese based NOx storage catalyst films decrease at 350 °C linearly with the NOx dose. The slope of the signal is proportional to the actual NOx concentration. The dosimeter principle is based on the sorption of NOx on the sensitive material. During NOx absence, the sensor signal remains constant, i.e. no desorption occurs. When a certain sorption state is reached, the sorbed species has to be desorbed thermally. To study the sorption processes on the NOx storage material, Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) was used. Different material compositions were investigated by DRIFTS on powdered catalysts and operando DRIFTS on NOx dosimeters themselves. On Al2O3 (catalyst support) no NOx sorbs. Manganese addition (Mn-Al2O3) leads to few detectable nitrites on Aluminum-sites during NOx exposure. On Potassium-loaded alumina (K-Al2O3), nitrites and nitrates form. The comparison of NO2 and NO proves that NO2 is sorbed directly as nitrate species and NO cannot be strongly sorbed as nitrate on K-Al2O3. The complete material composition K/Mn-Al2O3 shows strong nitrate bands during NO and NO2 exposure. An interplay of potassium and manganese when forming nitrates was found. Operando DRIFTS confirms the direct relation between formed nitrates and complex impedance. Furthermore, it is proven that during thermal regeneration, sorbed nitrites and nitrates desorb completely and the sensor signal returns to its initial value. On the whole, the sorption behavior of the powders and the dosimeter behavior can be explained.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Institutionen der Universität: | Fakultäten > Fakultät für Ingenieurwissenschaften Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Funktionsmaterialien > Lehrstuhl Funktionsmaterialien - Univ.-Prof. Dr.-Ing. Ralf Moos Profilfelder > Advanced Fields > Neue Materialien Forschungseinrichtungen > Zentrale wissenschaftliche Einrichtungen > Bayreuther Materialzentrum - BayMAT Fakultäten Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Funktionsmaterialien Profilfelder Profilfelder > Advanced Fields Forschungseinrichtungen Forschungseinrichtungen > Zentrale wissenschaftliche Einrichtungen |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften |
| Eingestellt am: | 04 Sep 2020 07:33 |
| Letzte Änderung: | 13 Jun 2024 11:32 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/56791 |