Sr- and Mo-deficiency Sr1.95TiMo1−xO6–δ double perovskites as anodes for solid-oxide fuel cells using H2S-containing syngas

Sr- and Mo-deficiency SrTiMoO (STMO; x = 0–0.075) double perovskites are prepared and applied as potential anodes for solid-oxide fuel cells (SOFCs) operated in sulfur-containing syngas. The effect of Sr- and Mo- deficiency on the crystalline nature, electrical and thermal properties and electrochemical performance are investigated. The STMO crystallizes in a single-phase cubic perovskite structure and has excellent thermal and chemical compatibilities with CeGdO, CeSmO and LaSrGaMgO electrolytes. The conductivities of STMO in H at 550 °C–850 °C are higher than 160 S cm. The polarization resistance (R) of STMO is recorded as 1.451 Ω cm at 850 °C in H, which is 51% lower than that in pristine SrTiMoO, and the maximum power density (P) at 800 °C in H shows 41% increment as compared to SrTiMoO. The electrochemical performance of STMO is further enhanced by impregnation of Pd: the R is decreased from 0.73 Ω cm to 0.33 Ω cm for STMO and Pd-impregnated STMO (Pd-STMO) anodes, while the corresponding P in H increased from 649 to 1051 mW cm at 850 °C. The Pd-STMO shows high electrochemical property and durability in simulated coal syngas containing sulfur (3% HO), making it a promising anode for hydrocarbon-fueled SOFCs.