Atomically Dispersed Iron Active Sites on Covalent Organic Frameworks for Artificial Photosynthesis of Hydrogen Peroxide

Artificial photosynthesis has been regarded as a promising solution toward solar energy conversion, generating storable and transportable chemical fuels such as hydrogen (H2) and hydrogen peroxide (H2O2). However, the design of robust catalytic sites not only affects the activity, but also identify the atomic‐level correlation between active sites and natural photosynthesis performance. Herein, a synthesis method of single‐atomic Iron (Fe) active sites anchored on novel covalent organic framework (COF) for the production of H2O2 under visible light irradiation. When benzyl alcohol is the most sacrificial agent, the state‐of‐the‐art Fe‐based COF exhibits an excellent H2O2 generation rate of 4130 µmol g−1 h−1, over 5.3 times higher than that of pristine COF, achieving an apparent quantum yield of 6.4% at 420 nm. The enhanced photocatalytic performance is ascribed to the synergistic effect of atomically dispersed Fe sites and COF hosts, reducing the reaction energy barrier for the formation of *OOH intermediates and optimizing the adsorption of O2 and thus promoting two‐electron oxygen reduction reaction (ORR). This work establishes an atomic‐level engineering approach to build atomically dispersed Fe active sites on COF photocatalysts and provides in‐depth insight upon the ORR mechanism for promising artificial photosynthesis of H2O2. A synthetic route to synthesize single‐atom Fe sites immobilized on a novel COF. The Fe‐based COF exhibits an excellent H2O2 generation rate of 4130 µmol g−1 h−1. The excellent photocatalytic performance is ascribed to the synergistic effect of atomically dispersed metal sites and COF hosts, reducing the reaction energy barrier for the formation of *OOH intermediates.