Conseil national de recherches du Canada. Nanotechnologie
oxygen reduction; perovskite; mesoporous; Ag exsolution; ordered structure
For perovskites to become more competitive oxygen reduction reaction (ORR) catalysts, substantial progress is required to advance their enhanced catalytic activity and durability. Herein, a novel method is described to achieve high-performance perovskite ORR catalyst via combining nano architecture designs, internal structures engineering, and Ag nanoparticles (NPs) in situ exsolution. The as-synthesized Ag-(PrBa)0.95Mn2O5+δ catalyst exhibits favorable ORR activity with durability superior to the state-of-the-art Pt/C in alkaline solution. Several characterization techniques were applied alongside density functional theory calculations to understand the possible active sites and the synergistic coupling effects that contributed to the high ORR performance. The strong interfacial anchoring of Ag NPs on the ordered oxygen deficient perovskites leads to significant ligand effect and facilitates electron transfer and ion migration within the oxygen reduction reaction. The systematic engineering of perovskites described here represents a brand new approach to developing highly active and stable catalyst for energy conversion and storage.