Superior sensitive NiFe2O4 electrode for mixed-potential NO2 sensor

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.