Effect of Pd-impregnation on the electrochemical performance of Sr_0.8La_0.2TiO₃-Ce_0.9Gd_0.1O_1.95 composite anodes for solid oxide fuel cells

In order to improve the catalytic activity of Sr_0.8La_0.2TiO₃ (SLT)-Ce_0.9Gd_0.1O_1.95 (GDC) composite anodes, Pd was impregnated as a co-catalyst using a glycine mediated impregnation method. When glycine was added into the Pd precursor solution, nano-sized Pd particles with the average particle size being approximately 20 nm were homogeneously distributed onto the SLT-GDC backbone. The polarization resistance (R_p) was significantly reduced by the impregnation of Pd due to the enlargement of the triple phase boundary (TPB) length, which promotes ionic exchange reactions at the anode/electrolyte interface, as well as the dissociation of H₂ molecules. The maximum power density of the single cell also increased significantly as the amount of Pd increased. Moreover, the single cell with a Pd-impregnated SLT-GDC15 anode showed a comparable performance using both CH₄ and H₂ fuel, which indicates that the Pd-impregnated SLT-GDC composite anode can be used for hydrocarbon-fueled SOFC as well.