Performances of planar NO2 sensor using stabilized zirconia and NiO sensing electrode at high temperature

A planar NO2 sensor was fabricated by using yttria-stabilized zirconia (YSZ) and NiO sensing electrode (SE). The NO2 sensing characteristics of the sensor were examined for emission control applications at elevated temperatures. The planar sensor employing the 1300 °C-sintered NiO-SE could detect NO2 selectively even at 900 °C under wet condition, with acceptable NO2 sensitivity as well as response/recovery rates. The emf output of the sensor varied linearly with NO2 concentrations on a logarithmic scale in the range of 50–400 ppm. The sensing mechanism based on mixed potential for the present sensor was verified by means of polarization measurements.