Amperometric sensor based on NASICON and NO oxidation catalysts for detection of total NOx in atmospheric environment

A NASICON based amperometric sensor was designed for the detection of total NOx (NO+NO2) in air. To make the device sensitive to both NO2 and NO, the sensing electrode (Au) was covered with NO oxidation catalysts. With the sensing electrode potential fixed at −150 mV vs. reference electrode (Au), the device attached with double catalyst layers of WO3 and Pt(0.5 wt%)-loaded SiO2 produced current response proportional to the concentration of NO2 or NO up to 1 ppm at 150°C. In addition, the proportionality constants (sensitivity) were almost the same to NO and NO2. The current responses were barely affected by the coexistence of CO2 or H2O.