NO₂-sensing properties of La_0.65Sr_0.35MnO₃ synthesized by self-propagating combustion

Ultrafine-structure La_0.65Sr_0.35MnO₃ (LSM) powders synthesized by self-propagating combustion method have been used to fabricate sensing electrodes (SEs) for NO₂ mixed-potential sensors based on yttria-stabilized zirconia (YSZ). This type of sensor was found to provide better NO₂ sensitivity at 500 °C than sensors with LSM powders synthesized by traditional solid-state methods. The response values of the sensor have good linear relationship (sensitivity 36.6 mV/decade and linear fit 0.99) with the logarithm of NO₂ concentration varying from 30 to 500 ppm. The influence of sintering temperature (1000, 1100, 1200, and 1300 °C) on sensor response was also examined and was found to have a significant effect on the morphology of LSM-SEs. Moreover, in the presence of NO, CO₂, CO, and NO₂, the sensor exhibited good NO₂ selectivity.