Fabrication and performance of Pr-doped CeO2 nanorods-impregnated Sr-doped LaMnO3–Y2O3-stabilized ZrO2 composite cathodes for intermediate temperature solid oxide fuel cells

Praseodymium doped ceria (PCO) nanorods were successfully introduced into the porous LSM–YSZ composite electrode via an infiltration and in situ hydrothermal synthesis route. The phase, composition, and microstructure of the materials were studied by X-ray diffractometry (XRD), energy dispersion spectrometry (EDS), and scanning electron microscopy (SEM). The introduction of the PCO nanorods resulted in a significant performance enhancement of the LSM–YSZ electrode. At 973 K, the impedance of the LSM–YSZ electrode with PCO nanorods is 1.3 Ω cm2, less than one half of that of the alkali solution treated LSM–YSZ electrode, 3.4 Ω cm2, and one third of that of the bare LSM–YSZ electrode, 4.6 Ω cm2. Electrochemical impedance spectroscopic analysis on symmetric cells and cyclic voltammogram analysis on fuel cells indicate that the enhancement is mainly due to the shift of the dominant oxygen reduction reaction (ORR) mechanism from an LSM–YSZ related process to a PCO nanorods related process. Such enhancement is highly affected by the morphology of PCO.