Electron Donor–Acceptor Activated Single Atomic Sites for Boosting Oxygen Reduction Reaction

Abstract Fabricating efficient non‐platinum‐group‐metal catalysts for the oxygen reduction reaction (ORR) in proton‐exchange membrane fuel cells still remains a big challenge. This study creates a unique bamboo‐like architecture of Mn and Fe single atomic sites (SASs) anchored on core‐shell structure of nanopaticles@carbon nanotubes (MnFe SASs/NPs@CNTs) via a precursor route, where the Fe nanoparticles (NPs) (identified as γ‐Fe and Austenite) are confined into CNTs, such an architecture exhibits compelling ORR activity and durability in 0.1 m HClO 4 . Experiments and calculations both reveal that the electron donor–acceptor paradigm between Mn SASs and Fe NPs launches a lattice‐electron coupling mechanism not only increasing occupation of π ‐antibonding orbital in Mn− * O intermediates but also rising Jahn–Teller effect, thereby destabilize the Mn− * O intermediate and eventually facilitate the potential‐limiting step from * O to * OH. Such a coupling activation of the ORR‐inert Mn SASs greatly improves ORR performances of MnFe SASs/NPs@CNTs.