A limiting current oxygen sensor based on FeO1.5 doped LDC as dense diffusion barrier

(La0.4Ce0.6O2-δ)1-x(FeO1.5)x (x = 0, 0.03, 0.04, 0.10, and 0.20) was synthesized by co-precipitation method. Crystalline structure, microstructure, electronic and ionic conductivities were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Hebb-Wagner method, and AC impedance method, respectively. The effects of FeO1.5 dopant on the properties of samples were investigated. A limiting current oxygen sensor based on (La0.4Ce0.6O2-δ)0.96(FeO1.5)0.04 as dense diffusion barrier and 8YSZ as solid electrolyte was prepared by Pt paste bonding method. The effects of temperature and oxygen concentration on sensing performance were investigated. The XRD measurements showed that the solid solubility of FeO1.5 in La0.4Ce0.6O2-δ (LDC) was between 3 mol% and 4 mol%. The electrical conductivity analysis showed that (La0.4Ce0.6O2-δ)0.96(FeO1.5)0.04 had the highest electronic and ionic conductivities. The sensor had a good performance and the limiting current depended linearly on the oxygen concentration, and exponentially on 1/T.