High performance solid electrolyte-based NO2 sensor based on Co3V2O8 derived from metal-organic framework

Abstract In this paper, a well-performing solid electrolyte-based NO2 sensor was initially assembled by using Co3V2O8 derived from Co-V-MOF as sensitive electrode material and La10Si5.5Al0.5O26.75 as solid electrolyte. The sensor displayed excellent sensing behaviors towards NO2 by comparison with the sensor using Co3V2O8 fabricated from classical solid state method as electrode material at 575 °C. The sensor exhibited good response-recovery characteristics to different NO2 concentrations, with a sensitivity of 78.2 mV/decade in the NO2 concentration range of 50-500 ppm. The sensor also showed good repeatability, strong anti-interference ability to CH4, CO2, O2, NO and CO, as well as good long-term stability for 30 test days at 575 °C. In addition, the sensor had a low cross-sensitivity to water vapor in the relative humidity of 20%-98% at 575 °C. The good sensing behaviors could be attributed to the synergistic effect of highly disperse Co/V catalysis sites from Co-V-MOF as well as the larger three-phase boundary of Co3V2O8/ La10Si5.5Al0.5O26.75/NO2. The sensing mechanism of the sensor was investigated and it followed the mixed-potential model.