The Detection of Odor Vapors, H2S and CH3SH, by the Planar-Type Zirconia Sensor

The planar-type YSZ sensor with the Au and Pt electrodes was fabricated. The 5.4 mol% YSZ layer was formed on the alumina substrate and then heated at 1450 C. The Pt/YSZ electrode was formed on the YSZ layer by the screen-print method and heated 1400 C, and then the Au/YSZ electrode formed on the YSZ layer in the same way to the Pt/YSZ electrode and heated at 1000 C. The EMF response of the fabricated sensor to 0.4-3.5 ppm H2S and 0.015-0.12 ppm CH3SH at 520 C was examined. Sensing experiments were carried out using a conventional gas-flow apparatus. The sensor was exposed to air and test gases. The test gas was generated by the permeation tube. The potential difference between two electrodes of the sensor was measured by a digital electrometer (Advantest R8340).