Abstract
The discussion about the sensing mechanism of non-Nernstian electrochemical gas sensors with a semiconducting sensing electrode is still open. This work reports a study of the influence of the metallic electrode under the semiconducting metal oxide, Nb2O5, on the sensor response. Planar sensors based on tape-cast YSZ layers were fabricated. Two Pt or Au finger electrodes were deposited on one side of the layers. One of the electrodes was covered with a Nb2O5 thick film. The response to CO was studied performing electromotive force (EMF) measurements in the 450-650 °C temperature range. In order to better understand the sensing mechanism, the electrical measurements were correlated to catalytic measurements performed on both electrodes. With no catalytic electrodes, the adsorption-Fermi level related mechanism seems to prevail, while in the case of sensors with Nb2O5|Pt|YSZ electrode, the mixed potential theory is more adapted to explain the results.
Original language | English (US) |
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Pages (from-to) | 591-598 |
Number of pages | 8 |
Journal | Sensors and Actuators, B: Chemical |
Volume | 129 |
Issue number | 2 |
DOIs | |
State | Published - Feb 22 2008 |
Externally published | Yes |
Keywords
- Metallic electrode
- NbO sensing electrode
- TPR analysis
- YSZ-based gas sensors
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Metals and Alloys
- Instrumentation
- Materials Chemistry
- Surfaces, Coatings and Films
- Electrical and Electronic Engineering