Highly sensitive and selective stabilized zirconia-based mixed-potential-type propene sensor using NiO/Au composite sensing-electrode

A planar sensor using yttria-stabilized zirconia (YSZ) and each of NiO, Au and NiO/Au sensing-electrodes (SEs) was fabricated, and examined for detection of propene (C3H6) at 600 °C. It was found that, while the sensor attached with NiO-SE showed minor response to several examined gases, the sensor using Au-SE gave selective and sensitive response to C3H6. However, the stability of the sensor using Au-SE was not satisfactory. Interestingly, the sensor attached with the NiO/Au (composite)-SE exhibited rather high sensitivity, selectivity and good stability to C3H6. In addition, the sensitivity (Δemf) of the sensor was found to be invariant to the change in water vapor concentration in the range of 2–11 vol% in the sample gas. Based on the results obtained from the SEM observation, the response stability was discussed briefly.