Construction of Co4 Atomic Clusters to Enable Fe−N4 Motifs with Highly Active and Durable Oxygen Reduction Performance.

Fe−N−C catalysts with single‐atom Fe−N4 configurations are highly needed owing to the high activity for oxygen reduction reaction (ORR). However, the limited intrinsic activity and dissatisfactory durability have significantly restrained the practical application of proton‐exchange membrane fuel cells (PEMFCs). Here, we demonstrate that constructing adjacent metal atomic clusters (ACs) is effective in boosting the ORR performance and stability of Fe−N4 catalysts. The integration of Fe−N4 configurations with highly uniform Co4 ACs on the N‐doped carbon substrate (Co4@/Fe1@NC) is realized through a "pre‐constrained" strategy using Co4 molecular clusters and Fe(acac)3 implanted carbon precursors. The as‐developed Co4@/Fe1@NC catalyst exhibits excellent ORR activity with a half‐wave potential (E1/2) of 0.835 V vs. RHE in acidic media and a high peak power density of 840 mW cm−2 in a H2−O2 fuel cell test. First‐principles calculations further clarify the ORR catalytic mechanism on the identified Fe−N4 that modified with Co4 ACs. This work provides a viable strategy for precisely establishing atomically dispersed polymetallic centers catalysts for efficient energy‐related catalysis. [ABSTRACT FROM AUTHOR]