High temperature gas coulometry
Dr. Jens Zosel
Kurt-Schwabe-Institut für Mess- und Sensortechnik Meinsberg e.V., Kurt-Schwabe-Straße 4, 04736 Waldheim, Germany, jens [dot] zosel [at] ksi-sensors [dot] de
Gas sensors based on solid oxide ion conductors are widely applied in combustion control and environmental monitoring [1]. Modern developments show, that they can also be used for high precision electroanalytical applications in gases. The contribution describes some aspects of historical development, basic parameters and electroanalytical measurements with these sensors in different applications. One example concerns the coulometric titration of oxygen in a broad measuring range, which is carried out with solid electrolyte cells (SEC) to characterize equilibria between oxide materials and the surrounding gas atmosphere [2]. Furthermore, the application of such SEC as chromatographic detectors is demonstrated [3]. It is shown that ultra-small amounts of exchanged oxygen well below 50 pmol are traceable in gases with p(O2) < 0.3 Pa. SEC exhibit very short response times in the millisecond range which enables its utilization as detector also for fast detection of concentration changes. The completeness of gas titration according to Faraday’s law has been demonstrated in the concentration range 1–200 vol.-ppm for different oxidizable and reducible gas components.
The contribution describes new results on the precision, stability and limits of detection of SEC and their dynamic behaviour, which are interesting for gas analysis, sensor development and high temperature material research.
References:
- Möbius H (1991) in: Göpel W, Hesse J, Zemel J N (Eds.), Sensors A comprehensive survey, Vol. 3, VCH, Weinheim, p. 1108
- Vashook V, Zosel J, Guth, U (2012) Journal of Solid-State Electrochemistry 16:3401-3421
- Schelter M, Zosel J, Oelßner W, Guth U, Mertig M (2013) Sensors and Actuators B: Chemical 187:209-214