at Google ScholarTitle data
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.
Vol. 320
(2020)
.
- No. 128568.
ISSN 0925-4005
DOI: https://doi.org/10.1016/j.snb.2020.128568
Abstract in another language
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.
Further data
| Item Type: | Article in a journal |
|---|---|
| Refereed: | Yes |
| Institutions of the University: | Faculties > Faculty of Engineering Science Faculties > Faculty of Engineering Science > Chair Functional Materials > Chair Functional Materials - Univ.-Prof. Dr.-Ing. Ralf Moos Profile Fields > Advanced Fields > Advanced Materials Research Institutions > Research Centres > Bayreuth Center for Material Science and Engineering - BayMAT Faculties Faculties > Faculty of Engineering Science > Chair Functional Materials Profile Fields Profile Fields > Advanced Fields Research Institutions Research Institutions > Research Centres |
| Result of work at the UBT: | Yes |
| DDC Subjects: | 600 Technology, medicine, applied sciences > 620 Engineering |
| Date Deposited: | 04 Sep 2020 07:33 |
| Last Modified: | 23 Jan 2023 14:42 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/56791 |