Sensing Performances of Mixed-potential Type NOx Sensor Attached with Oxidation-catalyst Electrode

The mixed-potential type NOx sensor attached with the oxidation-catalyst electrode was fabricated by laminating and sintering YSZ green-sheets, on which an NOx sensing electrode consisting of metal oxide (Cr2O3), an O2 sensing electrode, an NOx conversion electrode, Pt heaters, and a pair of thermocouples were printed. The sensor was capable of detecting low concentrations of total NOx. The use of the oxidation-catalyst electrode was found to decrease largely the interference of reducing gases (C3H8, CO) to the NOx sensitivity. The results obtained here indicate that the present sensor has great possibility of being utilized as an on-board NOx sensor.