Surface Functionalization with Ni of Fe_0.7Cr_1.3O₃/8YSZ Electrode in a Potentiometric Sensor To Selectively Detect C₂H₄

This work presents a multidevice potentiometric sensor consisting of Fe0.7Cr1.3O3/8YSZ//8YSZ//Pt to detect selectively C2H4 with a low cross-sensitivity to CO in diesel exhaust gases. The device has been designed as a multisensor to measure up to four channels at the same time. A dense 8YSZ disk is employed as oxide-ion conducting electrolyte where four rectangular-shape working electrodes (Fe0.7Cr1.3O3/8YSZ) are screen-printed in one face while one common cross-shape reference electrode (LSM/8YSZ) is screen printed in the back face. Two major improvements are proposed in this work: first, change the reference electrode from state-of-the-art Pt to LSM/8YSZ, inexpensive and more active to oxygen. And second, increase the catalytic activity of the working electrode to improve the response of the sensor under wet conditions. The surface activation by nickel and ruthenium nanoparticles deposition enables reduction of the cross-sensitivity toward CO even in wet atmospheres. Ni nanoparticles selectively boost the electrochemically driven oxidation to C2H4 with respect to CO oxidation, as inferred by impedance spectroscopy analysis.