Mixed potential type ppb-level acetaldehyde gas sensor based on stabilized zirconia electrolyte and a NiTiO3 sensing electrode

•NiTiO3 sensing electrode was applied to fabricate YSZ-based mixed potential type sensor for sensitive detection of acetaldehyde at 575 °C.•The sensor using NiTiO3-SE calcined at 1000 ℃ exhibited the highest response value to 50 ppm acetaldehyde and low detection limit of 200 ppb.•The sensor also displayed rapid response rate, good reproducibility, selectivity, moisture insensitivity and stability to acetaldehyde.•The fabricated device was a promising candidate for sensitive detection of ppb-ppm concentrations of acetaldehyde in the atmosphere. An attempt has been performed to develop a selective and sensitive acetaldehyde gas sensor based on yttria-stabilized zirconia (YSZ) solid electrolyte in conjunction with NiTiO3 sensing electrodes (SEs) calcined at different temperatures (800, 1000 and 1200 ℃). Among all the evaluated sensing devices, the sensor attached with NiTiO3-SE calcined at 1000 ℃ was found to have a maximum sensing response value of −43 mV to 50 ppm acetaldehyde and a lower detection limit of 200 ppb at an optimal working temperature of 575 ℃. The response and recovery times of the sensing device to 50 ppm acetaldehyde were 10 and 26 s, respectively. The present sensor also exhibited a segmentally linear relationship between the ΔV values and the logarithm of acetaldehyde concentration in the range of 0.2–1 ppm and 1–200 ppm at 575 ℃ and the sensitivities were −3 mV/decade and −26.5 mV/decade. Furthermore, the developed sensor had a good selectivity, reproducibility, moisture insensitivity, as well as a high temperature stability for 20 days. On basis of the polarization-curve evaluation of the present sensor, the good agreement between the observed values and the estimated values revealed that the sensing mechanism based on mixed-potential model has been confirmed.