Pendant Engineering of Covalent Organic Frameworks for Photocatalytic Hydroperoxide Production.

Abstract

Covalent organic frameworks (COFs) have attracted much attention for their potential in photocatalytic hydrogen peroxide (H2O2) production. However, traditional COFs often suffer from sluggish charge transfer kinetics and a lack of highly electron-localized sites for O2 adsorption, leading to inefficient photocatalytic activity. Herein, we report a pore-channel electronic engineering strategy that introduces highly electron-localized cores into the pore channels of COFs by the regulation of heterocyclic pendants. The cores located in the channel of COFs acted as electron-rich active sites, enabling enhanced charge separation for photocatalytic H2O2 production. The polar furan groups were introduced onto the cores, further forming a powerful built-in electric field and hydrogen bond network within the channels, thereby accelerating the transport of electrons and protons. The furan-grafted COF (O-COF) showed a photocatalytic H2O2 production rate of 15,378 µmol h-1 g-1, with a yield 1.5-2.4 times higher than that of its counterparts. This work provides a valuable reference for the precise electronic regulation of pore channels in COFs to enhance photocatalytic performances.