Engineering Covalent Organic Frameworks for Decoupled Photocatalytic and Dark Photocatalytic Synthesis of H2O2

Abstract

Mimicking both the photo reaction and dark reaction units in the natural photosynthetic system offers a sustainable approach for the efficient capture and storage of solar energy. Here we demonstrate that an engineered quinoline-linked covalent organic framework (Py-1Q) can integrate electron transport and storage within a single material. Under visible light illumination, Py-1Q exhibits a H2O2 production rate of 1535 μmol g–1 h–1, 8.5 times higher than that of its imine counterpart. Moreover, part of the photo energy was stored in Py-1Q as free electrons during irradiation, which can be gradually released in the dark to further produce 95 μmol g–1 h–1 of H2O2. DFT calculations reveal that the enhanced delocalization of the lowest unoccupied molecular orbital of Py-1Q is critical for its charge storage property. This study expands the applications of functional COFs and offers new insights into the design of solar-energy storage materials.