Chiral memory-guided construction of fluorinated covalent organic frameworks for efficient photocatalytic hydrogen peroxide synthesis in seawater

Conventional photocatalysts face challenges in achieving efficient and stable H₂O₂ synthesis from seawater due to its high salinity, complex pollutants, and rapid charge carrier recombination. Herein, the chiral fluorinated covalent organic frameworks (PETG-COF-(Δ/Λ)) are proposed by precise condensation of (R/S)-1-phenylethylamine and 2,4,6-triformylphloroglucinol. PETG-COF-(Δ) yields a remarkable H₂O₂ production rate of 4967 μmol·g⁻¹·h⁻¹ in seawater under visible light illumination, representing a 2.3-fold enhancement compared to the achiral counterpart. Experimental results and theoretical calculations demonstrate that the Δ-configured chiral framework enhances the performance of the 2e⁻ oxygen reduction reaction (ORR) by optimizing the adsorption configurations of reactants and intermediates, and facilitating rapid charge carrier migration through the inherent asymmetric electric field of the chiral microenvironment. Notably, fluorination not only broadens light absorption but also creates hydrophobic channels and passivation layers that effectively block Cl⁻ corrosion and ensure activity retention over 66 h in a flow reactor. This work paves a new avenue for solar-driven H₂O₂ synthesis by chiral COFs and a theoretical basis for the design of seawater-adapted photocatalytic systems.