Tungsten Oxide-Based Semiconductor Sensor Highly Sensitive to NO and NO2

Abstract

Abstract A sintered sensor element based on WO3 was found to be very sensitive to NO and NO2. The sensitivity, defined as the ratio of the resistance in the gases to that in air, was as high as 31 and 97 to 200 ppm NO and 80 ppm NO2, respectively, at 300 °C. The element was well suited for sensing the gases at low levels. Satisfactory performances to NO and NO2 were exhibited in the regions of 0–800 ppm and 0–200 ppm, respectively.