A mixed potential-type NO2 sensor was fabricated using yttria-stabilized zirconia (YSZ) as the electrolyte and mesoporous WO3 as the sensing electrode for the detection of NO2 in vehicle exhausts. The mesoporous WO3 with a diameter of 7 nm was synthesized using the hard template method. The sensor showed excellent performance in the detection of 30–500[Formula: see text]ppm of NO2 at 300∘C and 500∘C. However, commercial WO3 only operate well at 500∘C. The response of the mesoporous WO3 was higher and the test temperature was lower compared to that of commercial WO3. XPS combined with NO2-TPD was used to explain the high activity of mesoporous WO3 at medium-low temperature, and the mechanism of mixed electromotive force was verified by electrochemical impedance spectroscopy. Furthermore, the sensor exhibited high NO2 selectivity in the presence of interfering gases, such as NO, CO, CO2 and NH3. Most importantly, the sensor had excellent repeatability and stability.
Toluene-sensing Properties of Mixed-potential Type Yttria-stabilized Zirconia-based Gas Sensors Attached with Thin CeO2-added Au Electrodes
