Regulating the Spin-State and Frontier Orbital of a Molecular FePc Catalyst by Interlayer Electronic Coupling for Enhanced ORR Activity

Development of efficient and durable catalysts for the oxygen reduction reaction is essential for the advancement of metal–air batteries and fuel cells, yet it remains a significant challenge. Here, we present an interlayer-coupling strategy to modulate iron phthalocyanine by adjacent carbon-supported cobalt species. The resulting FePc@CoNC demonstrates superior ORR activity, with a half-wave potential of 0.927 V and achieving a peak power density of 336 mW cm–2 alongside cycling stability exceeding 1527 cycles. Density functional theory analysis reveals that the adjacent Co single atoms and Co nanoparticles synergistically enhance the localization of Fe dz2 electrons while suppressing spin polarization of Fe 3d orbitals. This electronic modulation optimizes adsorption energetics of key intermediates involved in the rate-determining step, thereby accelerating ORR kinetics. These results elucidate the significance of interlayer electronic coupling in axially tuning spin states and frontier orbitals of molecular Fe–N4 centers, offering a general strategy for enhancing oxygen electrocatalysis through electronic structure engineering.