Sensing properties of YSZ-based NOx sensors with double-perovskite (La0.8Sr0.2)2FeNiO6-δ-sensing electrodes

In this work, a (La0.8Sr0.2)(2)FeNiO6-delta (LSFN) powder semiconductor oxide with a double-perovskite structure was synthesized by a polymeric precursor method to fabricate a sensitive electrode (SE) for a NO sensors based on yttria-stabilized zirconia (YSZ). The LSFN powder and the LSEN-SEs sintered at different temperatures (1000, 1100 and 1200 degrees C) were characterized by X-ray diffraction (XRD). The morphologies of LSFN-SEs were observed by environmental scanning electron microscopy (ESEM). The sensors with LSEN-SEs were tested over a temperature range of 550-800 degrees C. Electrochemical impedance spectroscopy (EIS) was also performed to investigate the electrochemical processes that are affected by the NO2 concentration. The results demonstrated that the double-perovskite type electrode material possessed good thermal stability. The NO2 sensitivity of the sensor was found to be modulated by the morphology of LSFN SE. The sensor showed a higher sensitivity and a better selectivity to NO2 than that to NO. The impedance changed when the NO2 concentration was varied, which was attributed to the interaction of the NO2 with the SE. (c) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.