Effects of YSZ addition on the response of La2CuO4 sensing electrode for a potentiometric NOx sensor

This study describes the effects of YSZ addition on the response of potentiometric gas sensor based on La2CuO4 sensing electrode. The YSZ with four concentrations (0, 2, 5 and 10 vol.%) are respectively added into La2CuO4 to enlarge the larger superficial area of the triple phase boundary (TPB). Obtained sensors are all highly sensitive to NO and NO2, but no responses to O2 and CO2. The biggest NO sensing is obtained by the sensor fabricated with 5 vol.% YSZ addition at 400 °C. This response behavior agrees with the scanning electron microscope and EDS spectrum results, indicating that appropriate superficial area of TPB can improve the sensor performance. In addition, the complex impedance of the sensor verifies that the triple phase boundary plays an important role on NO detection. Four sensors are all NO selective against O2, but their sensitivities are affected by CO2, CO and NO2. Interestingly, the response values and slopes of the sensor fabricated with 5 vol.% YSZ addition are always bigger than those of the sensor fabricated with pure La2CuO4 in the cases of NO selectivity against CO2 and CO.