Superior electrochemical performance of non-precious Co-Ni-Mo alloy catalyst-impregnated Sr₂FeMoO_6-δ as an electrode material for symmetric solid oxide fuel cells

Double perovskite-based Sr₂FeMoO_6-δ (SFM), as an electrode material for symmetric solid oxide fuel cells (SOFCs), has been synthesized by a sucrose-modified combustion technique. SFM showed metallic conducting behavior with a conductivity of 215.72 S cm⁻¹ in dry H₂ at 800 °C. The polarization resistance (R_p) for H₂ oxidation, evaluated using half-cell symmetry, was recorded as 0.192 Ω cm² under humidified H₂ at 800 °C. Improved catalytic activity was accomplished by impregnation of Pd or Co-Ni-Mo (0.1:5:1 molar ratio, CNM) via a glycine-mediated impregnation technique. The R_p values for the Pd- and CNM-impregnated SFM were 0.087 and 0.060 Ω cm², respectively, under humidified H₂ at 800 °C. The symmetric SOFC with an La_0.8Sr_0.2Ga_0.8Mg_0.2O_3-δ (LSGM) electrolyte and a CNM-impregnated SFM electrode showed maximum power densities of 1066 mW cm⁻² and 480 mW cm⁻² at 800 °C under humidified H₂ and CH₄, respectively.