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

Abstract

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.