Impedancemetric NOx Sensors Based on LSM and LSM-Au Sensing Electrodes

Dense strontium-doped lanthanum manganite, La0.8Sr0.2MnO3 - LSM and LSM composite electrodes containing Au were studied as NOx sensing electrodes. The sensors were compared according to their NOx sensitivity and cross-sensitivity to H2O and CH4. LSM-Au composite electrodes demonstrated improved sensitivity and selectivity to NOx, in comparison to LSM electrodes. The stability and accuracy of LSM and LSM-Au based NOx sensors was also evaluated. The LSM-Au based NOx sensors showed stable sensing performance both in dry and humidified gas conditions. The sensing response for LSM-Au based sensors was accurate to within 2 - 3 ppm NO for temperature perturbations of ± 5 °C.