Preparing Ruthenium Complex-Contained DaTp COFs via π–π Interactions for Visible-Light-Driven Photocatalytic Hydrogen Peroxide Production

Hydrogen peroxide (H₂O₂) is a crucial energy carrier with growing significance in sustainable energy systems. Covalent organic frameworks (COFs) have recently emerged as promising materials for efficient H₂O₂ photosynthesis, while transition-metal complexes are recognized for their efficacy as molecular photocatalysts in H₂O₂ production. This study introduces a novel π-π interaction strategy to immobilize ruthenium complexes into COFs, using DaTp COF as a model system. This approach significantly enhances the photocatalytic activity for H₂O₂ production, achieving an initial rate of 3276 μmol g^-1 h^-1 without using scavengers under visible-light irradiation (λ > 420 nm). Notably, incorporating ruthenium complexes optimizes the oxygen reduction reaction pathways, shifting from a less efficient four-electron process to a more efficient two-electron process. Density functional theory calculations further reveal that ruthenium complexes not only broaden the light absorption spectrum of the COF but also increase water affinity, directly contributing to H₂O₂ generation. These findings offer a strategic framework for designing and enhancing COFs in H₂O₂ photosynthesis applications.