Search

Abstract A spinel-type metal oxide NiFe 2 O 4 prepared by solid state synthesis was utilized as sensing electrode on a YSZ (yttria stabilization zirconia) based mixed potential NO 2 sensor. NO 2 sensing performances were evaluated at an operating temperature range of 350–500 °C. The sensor exhibited maximum response (81.3 mV to 100 ppm NO 2) at 400 °C and optimal sensitivity of 82.8 mV/decade at 450 °C. Both cycling response and cross-sensitivity were evaluated, indicating good stability and selectivity. Furthermore, the EIS (electrochemical impedance spectrum) was also investigated to claim its sensing mechanism. [ABSTRACT FROM AUTHOR]

In this work, a (La0.8Sr0.2)2FeNiO6−δ (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 x sensors based on yttria-stabilized zirconia (YSZ). The LSFN powder and the LSFN-SEs sintered at different temperatures (1000, 1100 and 1200°C) were characterized by X-ray diffraction (XRD). The morphologies of LSFN-SEs were observed by environmental scanning electron microscopy (ESEM). The sensors with LSFN-SEs were tested over a temperature range of 550–800°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. [ABSTRACT FROM AUTHOR]