Temperature dependency of activity of nano-catalysts on La0.6Sr0.4Co0.2Fe0.8O3-δ cathode of solid oxide fuel cells

In this study, Ag-ceria, Co-ceria, and Ba0.5Sr0.5Co0.8Fe0.2O3 nano-catalysts were introduced onto the structure of La0.6Sr0.4Co0.2Fe0.8O3-delta cathode of solid oxide fuel cells through infiltration technique and the electrochemical features of the infiltrated cathodes were examined by electrochemical impedance spectroscopy and analysis of distribution of relaxation times in the temperature range of 500-800 degrees C. The results revealed that Ba0.5Sr0.5Co0.8Fe0.2O3 exhibits considerable promoting behavior in the upper portion of the studied temperature range, while Co-ceria demonstrates significant catalytic activity for the oxygen reduction reaction at lower temperatures probably due to the active valence exchange of cobalt species in the spinel structure of cobalt oxide. Analysis of distribution of relaxation times revealed that low frequency arc of the impedance spectra is effectively hampered as a result of Ag-ceria and Co-ceria infiltration. Cathodic polarization of the infiltrated cells showed stable performance of the infiltrated electrodes over 50 h at 700 degrees C. [GRAPHICS] .