Mixed-potential based direct catalyst conversion sensor : Independency of the sensor response from oxygen, electrode material, and from the type of analyte

Titelangaben

Ritter, Thomas ; Hagen, Gunter ; Moos, Ralf:
Mixed-potential based direct catalyst conversion sensor : Independency of the sensor response from oxygen, electrode material, and from the type of analyte.
In: 17th International Meeting on Chemical Sensors - IMCS 2018. - Wien , 2018 . - S. 132-133
ISBN 978-3-9816876-9-9
DOI: https://doi.org/10.5162/IMCS2018/GS3.4

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Abstract

On-board diagnostics (OBD), which ensures the functionality of exhaust gas aftertreatment systems of combustion engines, needs reliable gas sensors. Therefore, we investigate a sensor that is able to determine directly catalyst conversion (between 0 and 100%). A mixed-potential is formed at two similar electrodes connected to different gas atmosphere, e.g. up- and downstream of a catalyst. Here, it is simulated by gas mixtures containing an analyte, e.g. a hydrocarbon. These mixtures can be adjusted so that different conversion of the catalyst is simulated. Identical analyte concentration indicate zero conversion and zero sensor response. The higher the catalyst activity is, the lower is the analyte concentration downstream of the catalyst and the mixed-potential at the second electrode increases. Theoretically, the sensor signal is only dependent on the conversion of the catalyst but on the analyte concentration of the feed gas. In this work, we verify these considerations for the first time also for the case of analyte mixtures, Au-electrodes, or varying oxygen contents.