Impedancemetric sensor based on YSZ and In2O3 for detection of low concentrations of water vapor at high temperature

We report here an impedancemetric stabilized-zirconia-based sensor with oxide sensing electrode (SE) for the detection of low concentrations of water vapor at high temperatures. Among various single-oxide SEs examined, the In2O3-SE gave the highest sensitivity to H2O at 900 degreesC. The sensitivity varies linearly with the concentration of H2O on a logarithmic scale over a wide range of 70-30,000 ppm at 900 degreesC. In addition, it was found that 90% response and recovery times were rather quick (less than two and five seconds, respectively), and the reproducibility of the sensitivity was also satisfactory. Furthermore, the present sensor could detect H2O in a wide temperature range of 500-900 degreesC. (C) 2004 Elsevier B.V. All rights reserved.