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

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-COF_BD 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-COF_BD-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.