PdO/ZrO2 engineered (La0.8Sr0.2)(0.95)MnO3-delta-(Y2O3)(0.08)(ZrO2)(0.92) cathode for use in intermediate temperature solid oxide fuel cells

摘要

To enhance the electrochemical performance of (La0.8Sr0.2)(0.95)MnO3-delta-8 mol. % Y2O3 stabilized ZrO2 (LSM-YSZ) cathode at reduced temperatures, PdO and ZrO2 (Pd/Zr = 0.8/0.2) are co-infiltrated into the LSM-YSZ scaffold. Such prepared composite cathode is investigated at temperatures between 600 and 750 degrees C and cathodic current densities of 400 and 800 mA cm(-2). It is observed that PdO particles are uniformly deposited on the surface of the LSM-YSZ and surrounded by nano-sized ZrO2 particles. This distinctive microstructure possesses improved thermal stability under current at 750 degrees C due to the hindering effect of ZrO2 on the agglomeration and growth of PdO particles. As a result, the electrocatalytic activity of the cathode for oxygen reduction reaction (ORR) is greatly enhanced due to presence of the self-limited PdO particles. At open circuit voltage, the initial polarization resistance decreases from 1.68 to 0.40 Omega cm(2) as temperature increases from 600 to 750 degrees C; and the polarization resistance is fully stabilized at the level of 0.36 and 0.34 Omega cm(2), respectively, after current polarization at 750 degrees C under 400 and 800 mA cm(-2) for less than 200 h. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.