Permanent Oxidative Dipole Engineering in Quinoline COFs for Boosting Exciton Dissociation and Oxygen Activation in H2O2 Photosynthesis

Abstract

ABSTRACT Despite their robust stability, fully conjugated quinoline‐linked covalent organic frameworks suffer from highly delocalized electron distributions and a homogeneous electrostatic potential, which physically cause high exciton binding energies and poor oxygen activation that severely limit photocatalytic H2O2 production. To fundamentally disrupt this electronic uniformity, we propose a permanent oxidative dipole (POD) strategy, where site‐selective oxidation of quinoline nitrogen atoms, synthesized via one‐pot [4+2] annulation, precisely embeds N+–O− dipole pairs into the NQ‐COFBD framework. These POD sites trigger localized charge polarization, producing a triple synergistic effect: a strengthened built‐in electric field (dipole moment increases from 1.08 to 2.08 D), a lowered exciton dissociation barrier (binding energy drops from 44.7 to 20.3 meV), and accelerated charge carrier transport (surface potential rising by a factor of 1.26). Crucially, the POD sites construct spatially decoupled redox dual‐centers that drastically reduce the kinetic barrier of the ORR rate‐determining step, with the *OOH formation energy lowered by 0.77 eV. Consequently, NQ‐COFBD‐O achieves a remarkable H2O2 production rate of 4,569 µmol g−1 h−1 under visible light without sacrificial agents (a 1.89‐fold enhancement), with an apparent quantum yield of 6.1% at 460 nm, and this strategy is also validated in another quinoline system with a 1.86‐fold improvement.