Charge‐Modulated Triple‐Pore Covalent Organic Frameworks with Tunable Metal Centers for Efficient Carbon Dioxide Photoreduction

Abstract Covalent organic frameworks (COFs) are crystalline porous polymers with diverse structures and tunable functions. Building hierarchical porosity in 2D COFs allows integration of complex pores with adjustable metal centers for precise charge modulation—key for enhancing light‐driven catalysis, though still challenging. Herein, a bipyridine‐based COF (TB‐COF) featuring three distinct types of pores is achieved using a desymmetrization strategy based on a modified D 2h ‐symmetric monomer. The high crystallinity and uniform triple pores of TB‐COF are unequivocally characterized via high‐resolution transmission electron microscopy (HR‐TEM). Post‐synthetic metalation with Co 2 ⁺, Ni 2 ⁺, and Cu 2 ⁺ incorporates active sites into the bipyridine units. Leveraging their well‐ordered hierarchical porous structure and active metal sites, these metalated COFs are investigated as photocatalysts for CO 2 reduction. Notably, the Co‐functionalized COF (Co‐TB‐COF) exhibits a high CO production rate of 12385 µmol g −1 h −1 with a selectivity of 88.4% over H 2 . Mechanistic investigations, supported by experimental data and theoretical calculations, confirm that the embedded metal sites are crucial to enhance photoinduced charge separation and lower the activation energy for intermediate *COOH formation, thereby boosting photoreduction efficiency. This study presents a novel strategy for the design of intricate COF architectures and elucidates the previously unexplored functionalities of hierarchically porous COFs.