A new sensor to monitor the degradation of three-way catalyst was designed by stacking three layers of the same YSZ (Yttria Stabilized Zirconia)-Al2O3 porous composite with two Pt electrodes being inserted in between. Each composite layer could serve as an oxide-ionic conductor as well as a gas diffusion barrier. Under an appropriate polarization voltage (0.4 V) applied between the Pt electrodes, the central layer attached with the electrodes, Pt|YSZ-Al2O3|Pt, worked as an oxygen pumping cell, while the upper or lower YSZ-Al2O3 layer worked as a gas diffusion barrier to provide the limiting current with respect to excess O2 in the fuel-lean atmosphere or that with respect to excess reducing gases like CO, H2, and CmHn in the fuel-rich condition. The amperometric signal was well proportional to the deviation of air/fuel ratio from the stoichiometric one so that a wide range of catalyst degradation could be monitored very well by this sensor. This sensor has advantages of simple operating algorithm, easy fabrication, and high thermal shock resistance.
ASJC Scopus subject areas
- Analytical Chemistry
- Electrical and Electronic Engineering