An Na + conductor-based amperometric sensor was designed for the detection of total NO x (NO+NO 2) in air. An original amperometric device, attached with a layer of NaNO 2 on the counter electrode (Au) was sensitive to NO 2, but insensitive to NO. In order to make the device sensitive to NO, the sensing electrode (Au) was covered with double layers of catalysts to oxidize NO to NO 2, i.e., WO 3 and Pt (0.5 wt %)-loaded SiO 2. At the sensing electrode potential fixed at -150 mV vs. the reference electrode (Au), the current response was proportional to the concentration of NO 2 or NO up to 1 ppm at 150 °C. In addition, the proportionality constants (sensitivity) were almost the same to NO and NO 2. The current responses were hardly affected by the coexistence of CO 2 and H 2O. The NO x sensing mechanism of the present sensor was briefly discussed.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Science(all)
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering