Enhancing CO2 Photoreduction Efficiency Through Improved Interaction Enabled by a Decorated Covalent‐Organic Framework

Abstract Photoreduction of CO 2 is often hindered by the sluggish kinetics for its activation. Refinement of host–guest interactions is an effective strategy to overcome this barrier. Here, we report the immobilization of active Co(II) sites within a covalent‐organic framework (COF) with a one‐dimensional (1D) chain structure, Co‐PyPDA‐COF, which demonstrates a remarkable CO generation rate of 30.5 mmol g −1 h −1 and a high CO selectivity of 95.8% in 2 h for CO 2 photoreduction at room temperature. The pore size of Co‐PyPDA‐COF is comparable to the diameter of CO 2 , which allows simultaneous interaction of a single CO 2 molecule with the two Co(II) sites. The enhanced interaction result in increased local CO 2 pressure, limited CO 2 diffusion after adsorption, shortened distance for photoelectron transfer, and reduced energy barrier for the rate‐determining step in CO 2 reduction, promoting CO 2 activation and conversion. This work opens a new way to design efficient catalysts by optimizing the pore size of the host.