Co₂MnO₄ spinel-palladium co-infiltrated La _0.7Ca_0.3Cr_0.5Mn_0.5O _3-δ cathodes for intermediate temperature solid oxide fuel cells

The effect of co-infiltration of Co₂MnO₄ (CM) spinel oxides and Pd on the electrochemical activity and microstructure stability of La_0.7Ca_0.3Cr_0.5Mn_0.5O _3-δ (LCCM) cathodes for the O₂ reduction reaction of intermediate temperature solid oxide fuel cells (IT-SOFCs) has been investigated in detail. The microstructure, thermal stability, electrochemical activity and stability of the Co₂MnO₄-Pd/PdO powders and Co₂MnO₄-Pd/PdO co-impregnated LCCM cathode were measured using thermal gravimetric analysis, X-ray diffraction, scanning electron microscopy and electrochemical impedance spectroscopy. The results indicate that the addition of spinel oxides effectively inhibits the growth and coalescence of the Pd/PdO nanoparticles and stabilizes the microstructure of the Pd/PdO at high temperatures. The best electrochemical activity and stability of LCCM cathodes were obtained on the cathode co-infiltrated with 50 wt% PdO/50 wt% Co₂MnO₄. The enhancement is due to the significantly improved stability of the microstructure as a result of the inhibited grain growth and agglomeration of Pd/PdO nanoparticles by the co-infiltrated Co ₂MnO₄ spinel phase. © 2011 Elsevier B.V. All rights reserved.