Develop Complex Photocatalytic System of D‐π‐A‐type Conjugated Porous Polymers and Benzyl Alcohol Mediated Autocatalysis for Practical Artificial Photosynthesis of H₂O₂

Artificial photosynthesis of H₂O₂ is conceived to be an ideal approach for replacing the industrial anthraquinone method that suffers from hefty energy penalties and environmental toxicity. However, the low concentration of H₂O₂ resides as the biggest hurdle for industrial production. Herein, with a focus on fabricating high-performance heterogeneous photocatalysts and establishing a highly efficient complex photocatalytic system, we report the preparation of D-π-A-type conjugated porous polymers containing a photosensitizer and redox-active anthraquinone moiety for endowing highly efficient H₂O₂ production up to 3.0 mmol g^-1 h^-1. Further, by exploiting the autocatalytic photooxidation feature of benzyl alcohol, •OOH as the key species contributing to H₂O₂ formation received a substantial accumulation, which stems from the collaboration of the photocatalytic and autocatalytic cycle. Mechanistically, the hydrogen bonding and π-π stacking between the photocatalyst and benzyl alcohol are formed to lower the free energy of the transition states, thus leading to unprecedentedly high efficiency in the photosynthesis of H₂O₂ up to 140.4 mmol g^-1 h^-1, with the concentration of 35.1 mmol L^-1 and an apparent quantum yield of 49%. This work provides critical insights in advancing sustainable energy conversion research.