Ferredoxin-Inspired Stereoisomeric Fe₂CN-Bridge-S Dual Atom Catalyst for Enhanced Acid Oxygen Reduction Reaction

The bimetallic center catalyst (DMC) injects new vitality into the accelerated oxygen reduction reaction (ORR) due to its unique structure. The regulation of the coordination environment composition and spatial structure of metal active centers also provides opportunities for optimizing the performance. Herein, we have successfully constructed stereoisomeric Fe₂CN-bridge-S (abbreviated as Fe₂CN-b-S) catalysts based on the biomimetic Fe-S cluster structure of ferredoxin. Adjacent Fe dual atoms skillfully weaken the O-O bond, crafting a peroxide bridge-like adsorption configuration. The incorporation of S atoms meticulously constructs the stereo configuration of active Fe sites, thereby inducing greater structural deformation tension and a downward shift in the Fe d-band center. These factors collectively facilitate the release of the OH* intermediate. Meanwhile, the reasonable spatial configuration of S can promote the optimal rigid structure of Fe diatomic active centers, improving the stability of the ORR reaction process. Thus, the Fe₂CN-b-S catalyst, which has a half-wave potential of 0.865 V, demonstrates superior ORR activity in comparison to Fe₂CN. This study offers a perspective on the joint regulation of elemental composition and geometric arrangement for enhanced catalytic activity in oxygen reduction.