From Cucurbit[7]Uril Armor‐Equipped Ferrocene to Nitrogen Self‐Doped Porous Carbon Hosting Fe Single Atoms and Atomic Clusters for ORR and Zinc‐Air Batteries

Abstract

ABSTRACT Achieving both high activity and metal loading of atomically dispersed metal sites in M─N─C catalysts remain a formidable challenge. Herein, we employ the macrocyclic supramolecule cucurbit[7]uril (CB[7]) as a nanocage precursor and ferrocene (Fc) as a metal source, respectively. Through spontaneous host–guest self‐assembly, an angstrom‐level space‐confined precursor (Fc@CB[7]) was constructed, providing a well‐defined molecular scaffold for oxygen electrocatalysts. The resulting Fc@CB[7] complex exhibits a cage‐with‐lid geometry, endowing it with the structural characteristics of a metal monatomic precursor. Upon coating the Fc@CB[7] complex with ternary eutectic salts (NaCl, KCl, ZnCl 2 , named TESs) and subjecting it to pyrolysis, we obtained a novel oxygen electrocatalyst, denoted Fe AC ─Fe SA /N─CBC 0.7 , featuring coexisting Fe atomic clusters and Fe single atoms. The deliberately designed Fe AC ─Fe SA /N─CBC 0.7 catalyst delivers a remarkable half‐wave potential ( E 1/2 ) of 0.915 V and outstanding Zn–air battery (ZAB) performance. Density functional theory (DFT) calculations identify the presence of Fe 7 clusters that modulate the local electronic configuration of Fe─N 4 sites and weaken *OH adsorption, thereby accelerating the oxygen reduction reaction (ORR) kinetics. This work not only paves a way between supramolecular chemistry and electrochemistry but also provides fundamental insights into the structure–activity relationship of Fe AC ─Fe SA /N─CBC 0.7 for ORR.