Mixed-potential-type zirconia-based sensor using Ni-Ti-O sensing electrode for detection of propylene

The mixed-potential-type sensors using yttria stabilized zirconia (YSZ) and various oxide-based sensing electrodes (SEs) were examined for detection of propylene (C
₃
H
₆
). As a result, the sensor attached with NiO-SE was found to exhibit highly sensitive but not well selective response to C
₃
H
₆
at 600°C under the wet condition (5 vol.% H
₂
O). To improve the C
₃
H
₆
selectivity, NiO-SE was further mixed with each of several oxides (50 mol.%) which can form mechanical mixtures or mixed oxides. It was found that the sensor attached with NiTiO
₃
-SE (initial mixture: 50 mol.% NiO + 50 mol% TiO
₂
) gave highly selective and sensitive response to C
₃
H
₆
at 650°C. The electromotive force (emf) response of the present sensor varied linearly with the logarithm of C
₃
H
₆
concentration in the range of 10 - 800 ppm.