VOC detection by potentiometric oxygen sensor based on YSZ and modified Pt electrodes

The response of the electrode potential to several volatile organic compounds was examined for a concentration cell-type oxygen sensor with a Pt|8YSZ|Pt (ref. 21% oxygen) structure. The contamination of air with ppm levels of volatile organic compounds resulted a decrease in the oxide activity at the sensing electrode with a Pt layer, i.e., a decrease in the half-cell potential. The decrease of the potential at the Pt sensing electrode was modified with an over-coating of the Pt electrode with a second material. The formation of a dense Au layer on the Pt electrode was effectively decreased the half-cell potential with the VOCs. On the other hand, the over-coating of the Pt electrode with materials having a high catalytic activity of volatile organic compounds oxidation depressed the sensitivity to the volatile organic compounds.