Local Electron Donor Defects Induce Dipole Polarization Boosting on Covalent Organic Frameworks to Promote Photocatalysis

Covalent organic frameworks (COFs) have been remarkably evolved within the field of photocatalysis owing to their customizability and targeted functionalization. However, the exciton effect arising from the Coulomb interaction among electrons–holes cannot be disregarded. Exploring new approaches to regulate exciton dissociation on COFs to facilitate photocatalysis is significant. Within this work, localized defects were fabricated on the skeleton of the COFs by the one-step synthesis method of introducing monoaldehyde electron donors (pyrene, ferrocene, and triphenylamine). The formation of D–A configuration defects can directionally change the local electronic structure and charge distribution of COFs and induce enhanced dipole polarization, thus, promoting exciton dissociation and enhancing photocatalytic activity. Among them, the pyrene electron donor-constructed defective COF exhibited a 7.8-fold increase in the aqueous-phase oxygen-containing photopolymerization rate relative to the pristine COF, with a conversion rate of 80% within 30 min.