Impedancemetric NO2Sensor Based on CoCrFeO4Sensing Electrode and La9.4Ba0.6Si5.9W0.1O26.8Electrolyte with Phase Angle as Response Signals

An electrochemical impedancemetric NO2 sensor was prepared with Cr impregnated spinel-oxide CoCrFeO4 as a sensing electrode and La9.4Ba0.6Si5.9W0.1O26.8 as an electrolyte. A La9.4Ba0.6Si5.9W0.1O26.8 porous layer was made through screen printing, and a CoCrFeO4 sensing material was prepared through wet impregnation. The sensitivity of the NO2 sensor was tested using an electrochemical workstation, and phase angle θ was used as sensitive signals. Cr impregnated CoFe2O4 sensor exhibited higher sensitivity and shorter response time compared to CoFe2O4 sensor. The optimum temperature and test frequency are 550 °C and 0.1 Hz where the sensor shows high sensitivity and stability. A good linear relationship was observed between the θ sensitive signal and the logarithm of NO2 concentrations. The sensor had a sensitivity of 9.1123 and showed a good anti-interference performance for CO2, CH4, and H2.