Rational Design of Covalent Organic Frameworks with Redox-Active Catechol Moieties for High-Performance Overall Photosynthesis of Hydrogen Peroxide

Covalent organic frameworks (COFs) have emerged as promising candidates for solar-driven photosynthesis of hydrogen peroxide (H2O2), yet the development of high-performance COFs tailored for practical applications presents substantial challenges. This research introduces the integration of the redox-active catechol moiety into a series of COFs (TPE-COF-OH, TPB-COF-OH, and TPP-COF-OH), serving as the pivotal active site for photocatalytic oxygen (O2) reduction to H2O2 through a reversible catechol-quinone interconversion mechanism. This process facilitates the transformation of catechol to o-benzoquinone in the presence of molecular O2, while photoexcited electrons are utilized to revert o-benzoquinone to catechol, reducing the energy barrier for H2O2 synthesis. Notably, TPB-COF-OH demonstrates an unparalleled H2O2 production rate of 6608 μmol h–1 g–1, outperforming its molecular counterpart, TPB-COF-OMe, which lacks the redox-active catechol unit. Furthermore, TPB-COF-OH achieves a solar-to-chemical conversion efficiency of 0.84%, marking the highest value among COF-based photocatalysts in solar-driven H2O2 production. This investigation not only underscores the critical role of molecular engineering in enhancing COF performance but also broadens the horizon for solar-to-chemical energy conversion technologies.