Donor–acceptor sp2 covalent organic frameworks for photocatalytic H2O2 production and tandem bisphenol-A degradation

Abstract

Covalent organic frameworks (COFs) emerge as innovative photocatalysts featuring systematically tuned chemical structures, nano-porosity, and photoelectric properties. We have shown in the last years that COFs are excellent photocatalysts and they are able to produce hydrogen peroxide (H₂O₂) from oxygen and water. Despite the recent surge in the photosynthesis of H₂O₂ using COFs, its subsequent application for tandem pollutant remediation as a tangible green alternative to Fenton chemistry has not yet been comprehensively explored. In this study, we synthesized three highly crystalline sp² COFs with different donor–acceptor (D–A) strengths, employing triazine units as the electron acceptor moiety. The D–A alignment promotes photogenerated charge separation, augmenting the photocatalytic process, which resulted in the TMT-TT-COF achieving a H₂O₂ production rate of 1952 μmol g⁻¹ h⁻¹ without any sacrificial agents. The COFs also manifested a rapid photocatalytic degradation of bisphenol A (BPA) from a variety of real-life waterbodies. This study pioneers the in situ H₂O₂ production via COFs to subsequently generate other reactive oxygen species (ROS) for direct organic pollutant degradation in the visible region.