Dual modulation of metal center and pore topology in covalent organic frameworks for photoreduction of carbon dioxide to multi‑carbon fuels

The photocatalytic CO₂ reduction yielding C₂₊ products (C₂H₄, C₃H₆) represents a promising pathway to achieve the goal of carbon neutrality. Nevertheless, the intrinsic relationship between metal center and pore topology, which has a significant effect on C₂₊ product activity, remains to be elucidated. Herein, three covalent organic frameworks (COFs) with varying pore topologies were designed and metal centers were introduced through a post-modification strategy. The photocatalytic CO₂ reduction activity of BT-COF-Cu significantly surpasses that of its pristine COF and the reference copper COFs, exhibiting C₂₊ product yields of 12.9 μmol·g⁻¹·h⁻¹ for C₂H₄ and 0.8 μmol·g⁻¹·h⁻¹ for C₃H₆. The enhanced performance is attributed to the synergistic interaction between the metal center and the pore topology. This unique star-shaped Kagome topology not only facilitates rapid charge carrier migration to metal active centers for reduction reactions, but also boosts CO₂ adsorption and activation, collectively enhancing CO₂ photoreduction activity. This work provides a new perspective on the pore topology design of metallic COFs for efficient solar energy conversion and applications.