Mixed-potential type NH3 sensor based on La10Si5.5Al0.5O27 electrolyte and CuV2O6 sensing electrode

Abstract

The sensing performance of the mixed-potential type NH3 sensor mainly depends on the property of the sensing electrode. Herein, The CuV2O6 is synthesized by modified solid reaction and used as the sensing electrode for the mixed-potential type NH3 sensor based on La10Si5.5Al0.5O27 electrolyte. The influence of the sensing electrode sintering temperature on the responding performance of the sensor is investigated. The results show that the appropriate sintering temperature (600 °C) can both firmly integrate the CuV2O6 sensing electrode into La10Si5.5Al0.5O27 electrolyte and enhance the length of three phase boundaries comprised by NH3 / CuV2O6 sensing electrode / electrolyte. The sensor exhibits excellent sensing performance in NH3 concentration range of 25-300 ppm at the relatively lower temperature of 350 °C compared to the common operating temperatures for the mixed-potential type sensor. Introducing Ag particles into the CuV2O6 sensing electrode can improve the sensor's anti-interference to NOx. It is found that the response signals of the sensor with pristine CuV2O6 sensing electrode to 100 ppm NH3 are decreased by 58% and 65%, when sample gas contains 150 ppm NO2 or NO. While the response signals of sensor based on CuV2O6/0.22 mg Ag sensing electrode are decreased by only 22% and 14% under the same conditions. The potentiodynamic measurement results indicate that the present sensors follow the mixed-potential mechanism.