Enhancing oxygen reduction activity and CO2-tolerance of A-site-deficient BaCo0.7Fe0.3O3-δ cathode by surface-decoration with Pr6O11 particles

Sluggish oxygen reduction reaction (ORR) activity and poor CO 2 -tolerance has been the long-standing limitations for the application of alkaline earth metal oxide cathode for solid oxide fuel cells (SOFCs). Here we report this situation can be ameliorated with a composite cathode based on Ba 0.9 Co 0.7 Fe 0.3 O 3-δ (B90CF) by surface-decorated Pr 6 O 11 (PO) particles. A halved polarization resistance is obtained by B90CF-15PO (PO of 15 wt%) cathode (0.033 Ω cm 2 at 700 °C) compared to blank B90CF, suggesting boosted oxygen reduction reaction activity owing to the accelerated oxygen surface exchange kinetics introduced by PO particles. PO protective layer also brings up desirable CO 2 -tolerance for B90CF cathode due to the more stable fluorite cubic structure of PO and higher acidity of Pr 3+ /Pr 4+ than Ba 2+ , which ensures the stable operation of cells. This work demonstrates the positive potential of surface-decoration with PO in developing cathodes with high performance and CO 2 -tolerance. • B90CF-15PO cathode exhibits boosted ORR activity compared to B90CF. • Oxygen surface exchange kinetics of B90CF-15PO cathode is highly accelerated. • CO 2 -tolerance of B90CF-15PO is effectively enhanced with the protection of PO layer.