구리 치환 페로브스카이트 산화물 표면에서 동시에 발생하는 비정질화 및 나노촉매 형성

Title : Concurrent Amorphization and Nanocatalyst Formation in Cu-Substituted Perovskite Oxide Surface: Effects on OxygenReduction Reaction at Elevated Temperatures

Abstract :
The activity and durability of chemical/electrochemical catalystsare significantly influenced by their surface environments, highlightingthe importance of thoroughly examining the catalyst surface. Here,Cu-substituted LSCFO is selected, a state-of-the-art materialfor oxygen reduction reaction (ORR), to explore the real-time evolution ofsurface morphology and chemistry under a reducing atmosphere at elevatedtemperatures. Remarkably, in a pioneering observation, it is discovered thatthe perovskite surface starts to amorphize at an unusually low temperatureof approximately 100°C and multicomponent metal nanocatalystsadditionally form on the amorphous surface as the temperature raises to 400°C. Moreover, this investigation into the stability of the resulting amorphouslayer under oxidizing conditions reveals that the amorphous structurecan withstand a high-temperature oxidizing atmosphere (≥650°C) only whenit has undergone sufficient reduction for an extended period. Therefore, thecoexistence of the active nanocatalysts and defective amorphous surface leadsto a nearly 100% enhancement in the electrode resistance for the ORR over200 h without significant degradation. These observations provide a new cat-alytic design strategy for using redox-dynamic perovskite oxide host materials.

링크 : https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202404103