Construction of Co Atomic Clusters to Enable Fe-N Motifs with Highly Active and Durable Oxygen Reduction Performance.

Fe-N-C catalysts with single-atom Fe-N 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-N catalysts. The integration of Fe-N configurations with highly uniform Co ACs on the N-doped carbon substrate (Co @/Fe @NC) is realized through a "pre-constrained" strategy using Co molecular clusters and Fe(acac) implanted carbon precursors. The as-developed Co @/Fe @NC catalyst exhibits excellent ORR activity with a half-wave potential (E ) of 0.835 V vs. RHE in acidic media and a high peak power density of 840 mW cm in a H -O fuel cell test. First-principles calculations further clarify the ORR catalytic mechanism on the identified Fe-N that modified with Co ACs. This work provides a viable strategy for precisely establishing atomically dispersed polymetallic centers catalysts for efficient energy-related catalysis.