Simultaneous Cross-Linking and Ionization via One-Step Friedel–Crafts Alkylation for the Construction of Ionic Porous Organic Polymers toward Enhanced H2O2 Photosynthesis

Low surface area and poor hydrophilicity are major limitations that hinder further enhancement of H₂O₂ photosynthesis in aromatic polymer photocatalysts. A promising strategy involves the construction of ionic porous organic polymers (iPOPs) with both enhanced surface areas and hydrophilicity. This work proposed a “one stone, two birds” approach via a one-step Friedel–Crafts alkylation to simultaneously achieve cross-linking and ionization to synthesize tetraphenylethylene (TPE)-based iPOPs, denoted as TPE-NF. Compared to the iPOP, namely, TPE-NS with only ionization (9 m² g^–1), TPE-NF demonstrated a substantially enhanced surface area (1147 m² g^–1) while maintaining hydrophilicity despite the incorporation of various aromatic cross-linkers. Owing to improved O₂ utilization efficiency, enhanced photogenerated carrier separation and charge transfer efficiency, and prolonged fs-TA lifetime, TPE-NF achieved a H₂O₂ production rate of 3.49 mmol g^–1 h^–1 under air and pure water conditions, which only increased by 1.7% under an O₂-saturared condition. This demonstrated the effective O₂ utilization directly from air without the need of an external O₂ supply for TPE-NF, thereby reducing energy consumption. This study demonstrates that the design strategy based on a one-step reaction to achieve concurrent cross-linking and ionization to prepare iPOPs represents a promising approach for enhancing H₂O₂ photosynthesis.