High temperature calcination for analyzing influence of 3d transition metals on gas sensing performance of mixed potential sensor Pt/YSZ/LaMO 3 (M=Mn, Fe, Co, Ni)

In this work, the perovskite-type oxides LaMO3 (M=Mn, Fe, Co, Ni) were utilized for sensing electrodes of the electrochemical gas sensors based on the electrolyte YSZ (ZrO2+8%mol Y2O3). The sensors with configuration of Pt/YSZ/LaMO3 were sintered at high temperature of 1200°C in order to analyze influence of the 3d transition metals (M) on gas-sensing characteristics of the perovskite-type oxide electrodes. The sensors were investigated by exposing to various gases of NO2, NO, CO, C3H8 and CH4. The sensor Pt/YSZ/LaFeO3 had the best sensitive and selective characteristics to NO2 gas. The sensors Pt/YSZ/LaMO3 (M=Mn, Co, Ni) showed poor gas-selectivity. Valence variation of the 3d transition elements was used to explain the gas-sensing performance of the sensors Pt/YSZ/LaMO3. The electrical conductance behavior of the oxides LaMO3 was also considered as an important parameter that affected to sensitivity of the sensors Pt/YSZ/LaMO3, particularly in the high operating temperature.