Revealing the Orbital Interactions between Dissimilar Metal Sites during Oxygen Reduction Process

A FeCo/DA@NC catalyst with the well-defined FeCoN6 moiety is customized through a novel and ultrafast Joule heating technique. This catalyst demonstrates superior oxygen reduction reaction activity and stability in an alkaline environment. The power density and charge-discharge cycling of znic-air batteries driven by FeCo/DA@NC also surpass those of Pt/C catalyst. The source of the excellent oxygen reduction reaction activity of FeCo/DA@NC originates from the significantly changed charge environment and 3d orbital spin state. These not only improve the bonding strength between active sites and oxygen-containing intermediates, but also provide spare reaction sites for oxygen-containing intermediates. Moreover, various in situ detection techniques reveal that the rate-determining step in the four-electron oxygen reduction reaction is *O2 protonation. This work provides strong support for the precise design and rapid preparation of bimetallic catalysts and opens up new ideas for understanding orbital interactions during oxygen reduction reactions. The bimetallic FeCo catalyst is quickly synthesized by Joule heating technology, and the electron configuration is optimized by adjusting the spin configuration to achieve high oxygen reduction reaction performance.image

Automated summary

In this study, a FeCo/DA@NC catalyst with a well-defined FeCoN6 moiety is customized using a novel and ultrafast Joule heating technique. The catalyst shows excellent oxygen reduction reaction (ORR) activity and stability in an alkaline environment, surpassing the performance of Pt/C catalyst in power density and charge-discharge cycling of zinc-air batteries. The improved ORR activity of FeCo/DA@NC is attributed to the significantly changed charge environment and 3d orbital spin state, which enhance bonding strength between active sites and oxygen-containing intermediates and provide spare reaction sites. This work provides support for precise design and rapid preparation of bimetallic catalysts and offers new insights into orbital interactions during ORR.