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Hagen, Gunter ; Dubbe, Andreas ; Moos, Ralf:
Role of Pt in Impedance Based Zeolite Gas Sensors.
2007
Veranstaltung: Sensor 2007
, 22.-24.05.2007
, Nürnberg, Deutschland.
(Veranstaltungsbeitrag: Kongress/Konferenz/Symposium/Tagung
,
Sonstige
Präsentationstyp)
Abstract
Hydrocarbon (HC) gas sensors may be helpful for future on-board-diagnostics (OBD) of automotive exhaust gas aftertreatment systems (for example: passenger car OBD legislation requirements for non-methane HCs in 2010-2013). Several methods for HC detection (e.g. conductivity of semiconducting metal oxides, mixed potential principles on solid ion conductors or thermoelectric principles) are possible. A novel way of impedance based sensors utilizing zeolites as ion-conducting functional material is introduced. Such sensors consist of Au interdigital electrodes (IDE), covered by Pt-doped Na-ZSM-5 zeolites.
The microscopic sensing mechanism of the presented sensor setup is not fully elucidated yet, but experimental investigations show that a chromium(III)oxide interface between the Au electrode and the zeolite cover (with no Cr2O3 contact between the interdigital electrodes) is essential. Impedance Nyquist-Plots consist of a high-frequency semicircle, which is attributed to the zeolite ionic mobility, and low-frequency electrode contributions. By admixing of hydrocarbons to a wet oxygen-containing carrier gas flow, the low-frequency complex resistance increases strongly.
Without doubts, effects at the electrode are responsible for the measuring effect. The sensors show a highly selective and sensitive response behavior to HC. There are no cross-sensitivities toward H2 or CO, NO or CO2. This contribution emphasizes that also platinum is a indispensable component for this outstanding effect in addition to Cr2O3 at the interface. It will be shown that it must be present at the interface and also inside the zeolite pores.
Weitere Angaben
| Publikationsform: | Veranstaltungsbeitrag (Sonstige) |
|---|---|
| Begutachteter Beitrag: | Ja |
| Institutionen der Universität: | Fakultäten > Fakultät für Ingenieurwissenschaften Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Funktionsmaterialien > Lehrstuhl Funktionsmaterialien - Univ.-Prof. Dr.-Ing. Ralf Moos Fakultäten Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Funktionsmaterialien Profilfelder > Advanced Fields > Neue Materialien Forschungseinrichtungen > Forschungszentren > Bayreuther Materialzentrum - BayMAT Profilfelder Profilfelder > Advanced Fields Forschungseinrichtungen Forschungseinrichtungen > Forschungszentren |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften |
| Eingestellt am: | 09 Jun 2015 07:22 |
| Letzte Änderung: | 06 Apr 2016 08:01 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/14849 |