Mesoporous tungsten oxide electrodes for YSZ-based mixed potential sensors to detect NO2 in the sub ppm-range

[Display omitted] •Mesoporous WO3 with high surface area (209 m2/g) prepared using SBA-15.•Mesoporous WO3 used as sensing electrodes for ppb-level NO2 detection.•Excellent NO2 sensitivity, along with high selectivity and stability, was obtained.•The sensors using YSZ sold electrolyte followed the mixed-potential mechanism. Mesoporous WO3 with diameter of 7 nm and specific surface area of 209 m2/g was prepared by using SBA-15 as the hard template. Designed for ppb-level NO2 detection in air, the as-obtained mesoporous WO3 was employed as the sensing electrode to improve the sensitivity of a mixed-potential-type sensor based on yttria-stabilized zirconia electrolyte. This device showed high sensitivity to NO2 over the concentration range of 0.06–10 ppm at 500 ℃, and the electric potential difference (ΔV) showed good linear correlation with the logarithm of the NO2 concentration. The sensor exhibited high NO2 selectivity, along with excellent repeatability and stability as well. The mixed-potential sensing mechanism was also discussed based on the polarization curves and electrochemical impedances.