Electron‐Donors–Acceptors Interaction Enhancing Electrocatalytic Activity of Metal‐Organic Polymers for Oxygen Reduction

Abstract

AbstractCatalysts with metal‐Nx sites have long been considered as effective electrocatalysts for oxygen reduction reaction (ORR), yet the accurate structure‐property correlations of these active sites remain debatable. Report here is a proof‐of‐concept method to construct 1,4,8,11‐tetraaza[14]annulene (TAA)‐based polymer nanocomposites with well‐managed electronic microenvironment via electron‐donors/acceptors interaction of altering electron‐withdrawing β‐site substituents. DFT calculation proves the optimal −Cl substituted catalyst (CoTAA−Cl@GR) tailored the key OH* intermediate interaction with Co−N4 sites under the d‐orbital regulation, hence reaching the top of ORR performance with excellent turnover frequency (0.49 e s−1 site−1). The combination of in situ scanning electrochemical microscopy and variable‐frequency square wave voltammetry techniques contribute the great ORR kinetics of CoTAA−Cl@GR to the relatively high accessible site density (7.71×1019 site g−1) and fast electron outbound propagation mechanism. This work provides theoretical guidance for rational design of high‐performance catalysts for ORR and beyond.