Improving CO2 resistance in high-temperature humidity sensors using LaFeO3 sensing electrodes

Abstract

Yttria-stabilized zirconia (YSZ)-based amperometric humidity sensors are highly promising for in situ detection of high-temperature flue ducts due to their excellent stability and durability under extreme conditions. However, selectivity remains challenging due to the co-electrolysis of H₂O and CO₂, as these compounds have similar electrolysis voltages. In this study, LaFeO₃ is proposed as a sensing electrode to reduce CO₂ electrolysis and improve selectivity in amperometric humidity sensors. Analysis indicates that the improved selectivity is likely due to LaFeO₃’s lower electrochemical activity. Furthermore, the proposed sensor exhibits good repeatability and acceptable long-term stability for high-temperature humidity detection.