Development of ethanol and toluene sensing devices with a planar-type structure based on YSZ and modified Pt electrodes

A potentiometric gas sensor with a planar-type structure was fabricated and used to detect ethanol and toluene at sub-ppm levels. One of the Pt/YSZ electrodes of the (Pt/YSZ)|YSZ|(Pt/YSZ) sensor was coated with MgAl2O4 or Au/YSZ powder separately, and the electrode potential response to ethanol and toluene of these sensors was evaluated. The coating of the Pt/YSZ electrode induced a decrease in the oxide ion activity at the triple phase boundary, and the electrode potential, sensitivity and selectivity for the ethanol and toluene detection were improved. For the MgAl2O4-(Pt/YSZ)|YSZ|(Pt/YSZ) sensor, the electrode potential response to ethanol was higher than that of toluene, while for the (Au/YSZ)-(Pt/YSZ)|YSZ|(Pt/YSZ) sensor, the electrode potential response to toluene was higher than that of ethanol.