Comparison of the performances of ß-Alumina and YSZ potentiometric gas sensors for exhaust automotive application

In the past, we have deeply investigated the development of a beta-alumina potentiometric sensor with two coplanar metallic electrodes. Recently, many papers show an interest for similar device based on stabilized zirconia (YSZ) electrolyte. In this study, we compare the performances of these two types of sensors, in regards of their potential application for exhausts. Responses to CO, NO
₂
and hydrocarbon (named HC) were measured in a test bench at various concentrations (20-600 ppm), as a function of the sensor temperature in the range 350-600degC. The influence of NH
₃
which can be present in exhaust using SCR systems with urea was also examined in the range 5-50 ppm, with and without NO
₂
. Similar behaviours are obtained for both types of sensors concerning CO and HC detection: a maximum response is observed at 400-450degC. However, different responses are observed for NO
₂
, and thus for NH
₃
-NO
₂
mixtures. Hence, both sensors are interesting and can be complementary for final application.