(Invited) Unraveling the Oxygen Reduction Reaction Mechanism and Activity of d-Band Perovskite Electrocatalysts for Low Temperature Alkaline Fuel Cells

Oxides with a perovskite structure have been recognized as potential catalysts for application in low temperature alkaline fuel cells. Although perovskites have been investigated for several decades as electrocatalysts for the oxygen reduction reaction (ORR), only recently improvements in the ORR activity have been reported, when perovskites are combined with various carbons. This contribution shows the enhancement in the ORR activity when Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ is coupled with acid treated carbon black. Different mechanisms can account for the improved ORR activity of the composite cathode compared to the single catalyst. Perovskite surface utilization enhancement and synergistic ORR pathways will be discussed in this contribution.