High-performance of planar NO2 sensor using stabilized zirconia and NiO sensing electrode synthesized by microwave at high temperature

This paper focuses on the gas sensing properties of the mixed-potential-type yttria stabilized zirconia (YSZ)-based NO₂ sensor with NiO sensing electrode. The sensing characteristics of the sensors have been improved by controlling the microstructure of NiO sensing electrode synthesized with the microwave. The microstructure of NiO strongly depended on the microwave treatment temperature and the sintering temperature. The largest sensitivity of the sensor was obtained by using the NiO synthesized at 60°C and sintered at 1200°C, the slope of the dependence of EMF on the NO₂ concentration in the range of 20-500 ppm was 54 mV/decade at 850°C. It was also seen that the sensor showed a speedy response and recovery kinetics to NO₂. The sensing mechanism was confirmed to involve in the microstructure of oxide sensing electrode.