Engineering Proton Clamp Traps in Covalent Organic Frameworks for Boosting CO₂ Capture and Photoreduction

The targeted construction of efficient CO₂ capture platforms for photocatalysis remains a significant challenge. Herein, we precisely engineered a proton clamp within a series of covalent organic frameworks (COFs) to function as CO₂ traps, thereby significantly enhancing the photocatalytic reduction of CO₂ to CO. The proton clamp was rationally designed by using an S-shaped molecular motif featuring appropriate interatomic distances and strategically positioned protonation sites. Remarkably, the protonated COFs exhibited a superior CO production rate of 109 µmol g^-1 h^-1 in a gas-solid reaction condition. The experimental and theoretical investigations confirmed that the proton clamp not only facilitated efficient CO₂ trapping but also rapidly delivered protons to the active sites, accelerating the reaction kinetics. This work provides molecular-level insights into protonation strategies for optimizing photocatalytic CO₂ reduction, offering a new design principle for advanced COF-based photocatalysts.