Architecting Covalent Organic Frameworks across Dimensions for Efficient H2O2 Photoproduction

Rational design of dimensionally diverse covalent organic frameworks (COFs) with tailored functions has attracted much attention. However, the dimension and photocatalytic activity correlation remain confused, severely restricting the construction of efficient photocatalysts. Herein, we present a comprehensive investigation into the dimensional control of COFs for boosting overall H₂O₂ photogeneration. We ingeniously designed BYTT-COF and BYTD-COF with similar chemical compositions but distinct dimensionalities, which exhibit significant differences in H₂O₂ photosynthetic activity. Without any sacrificial agents, 2D BYTT-COF achieves an impressive H₂O₂ evolution rate of 9461 μmol g^–1 h^–1, 1.6 times higher than its 1D counterpart BYTD-COF, with a solar-to-chemical conversion efficiency of 1.02%. Extensive experimental and theoretical investigations indicate that while BYTT-COF and BYTD-COF possess similar photoredox catalytic centers, dimensional control implemented in BYTT-COF leads to an optimized spatial arrangement of catalytic sites and enhanced charge separation efficiency relative to BYTD-COF. Consequently, the activation energy barriers associated with *HOOH desorption and *OH formation within the H₂O₂ evolution dual paths are lower for BYTT-COF compared to BYTD-COF. Furthermore, solid H₂O₂ can be sustainably prepared from air, water, and natural sunlight by BYTT-COF. This study provides valuable insights into the dimensional engineering of COFs toward high-performance photocatalysts.