Molecular Space-Charge Layering in Ionic Covalent Organic Frameworks for Unidirectional Charge Transfer toward Efficient H₂O₂ Photosynthesis

Herein, we employed a solvent-free melt polymerization method to synthesize a highly crystalline <i>sp</i>² carbon-linked ionic COF, designated as TMB-COF-Br. Incorporating N⁺-functionalized pyridine units constructed as electron-withdrawing centers, a robust molecular space-charge layer was successfully engineered within the pristine skeleton.

The tailored electrostatic environment functioned as an intramolecular charge-rectifying valve along the <i>sp</i>² carbon-linked conjugation, which significantly promoted electron/hole dissociation and enabled directional charge transport, thereby markedly boosting photocatalytic H₂O₂ production. Furthermore, the localized electropositive microenvironment effectively stabilized the crucial *OOH intermediate via electrostatic interactions.