High performance mixed-potential type NO2 sensors based on three-dimensional TPB and Co3V2O8 sensing electrode

In this paper, a high performance YSZ based mixed-potential type sensor based on three-dimensional three-phase boundary (TPB) and a new type composite oxide Co3V2O8 as sensing electrode (SE) was fabricated for NO2 detection at 700 °C. The Co3V2O8 material was synthesized through sol–gel method, and the YSZ particle was mixed uniformly with Co3V2O8 in different mass fraction (0 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt% and 50 wt%) to form different three-dimensional TPB. The present study mainly focused on the effect of the TPB on NO2 sensing performances of sensor. Results showed that the sensor using sensing electrode Co3V2O8 + 40 wt% YSZ displayed the largest sensitivity in an NO2 concentration range of 10–400 ppm at 700 °C, which the slope was 85 mV/decade. The response for the sensor to 100 ppm NO2 was approximately 130 mV. Furthermore, the present sensor also displayed relatively good linearity, repeatability, stability, and cross-sensitivities. Such an enhancing effect on the sensing characteristics of the sensor may be ascribed to the enlargement of three-phase boundary through constructing the three-dimensional TPB.