Microenvironment Modulation of Single Cobalt Sites in Covalent Organic Frameworks with Serrated Stacking of Metallocorroles for Boosting Electrocatalytic Water Oxidation

Abstract The electrochemical oxygen evolution reaction (OER) is critically influenced by the rate‐determining step (RDS) and intermediate binding at catalytic sites, yet achieving precise control over these factors to promote the OER remains challenging. Enzymatic systems exemplify how catalytic efficiency is dictated by not only active centers but also their surrounding microenvironments. Drawing inspiration from this paradigm, serrated stacking cobalt‐corrole‐based covalent organic frameworks (Co‐CorCOFs) with well‐defined active sites are developed as models for systematical investigation and manipulation of electrocatalytic behavior. It is shown that remote microenvironment tuning via oriented functionalization of COF linkages effectively alters the electronic structures of both the COF backbone and Co sites. This results in distinct reaction kinetics and electron transfer in covalently assembled composite Co‐CorCOF/carbon nanotube (CNT) hybrids (Co‐CorCOF@CNTs). Notably, introducing quinoline moieties into the linkages significantly boosts OER activity in Co‐CorCOF‐3@CNT versus an unmodified Co‐CorCOF‐2@CNT. Mechanistic studies reveal that microenvironment engineering fine‐tunes the Co sites’ d‐band center, which facilitates oxygenated intermediate adsorption and shifts the RDS from *OH formation to *OH deprotonation with a substantial reduction in the energy barrier, thereby accelerating the reaction rate. This work offers a new avenue for the formulation of more efficient catalysts via a molecular‐level microenvironment modulation strategy.