Electronic Modulation of Fe‐N‐C by the Coexisted Cu Single‐Atoms and FeCu Atomic Clusters on Lignin‐Derived Porous Carbon Boosting Bifunctional ORR/OER Electrocatalysis

ABSTRACT Developing highly efficient single‐atom catalysts (SAC) for oxygen reduction/evolution reactions (ORR/OER) shows great promise in rechargeable Zn‐air batteries (RZABs). As one of the most appealing candidates for oxygen electrocatalysis, Fe‐N‐C catalysts are still suffered from the suboptimal adsorption of oxygen intermediates. Herein, a facile strategy to optimize the activity of Fe‐based SAC is achieved through the construction of well‐dispersed FeN ₄ /CuN ₄ dual single‐atom sites and FeCu atomic clusters on lignin‐derived porous carbon nanosheets (Fe,Cu‐DSAs/ACs) by engineering metal‐lignin coordination complexes. The optimized catalyst demonstrates remarkable bifunctional ORR/OER activity with a low potential gap of 0.686 V, which is comparable to benchmark Pt/C+RuO ₂ and even superior to previously reported non‐precious metal catalysts. When assembled in RZABs, it exhibits superior energy and power density, as well as excellent cycling stability up to 500 h. Theoretical calculations demonstrate that coexisting Cu‐N ₄ sites and FeCu atomic clusters could collaboratively break the symmetric electronic structure of Fe‐N ₄ and induce a downward shift in the d‐band center, thus reducing the adsorption energy of oxygenated intermediates and promoting both the ORR and OER performance. This work proposes a universal and sustainable strategy for electron regulation of M‐N‐C, thereby offering key insights for the design of advanced multifunctional electrocatalysts for future energy applications.