All-Dry Molecular Scale Processing for Shaping Open Pockets with CO₂ Affinity in a Covalent Organic Framework

Carbon dioxide capture is key to achieving carbon neutrality and addressing climate change. Covalent organic frameworks (COFs) with tailored pore structures have emerged as potential candidates for CO₂ adsorption. However, previous postsynthetic modification methods often face an inevitable trade-off between increasing adsorption sites and maintaining pore accessibility. Herein, we report an all-dry molecular scale processing (MSP) approach that forms open pockets in COF mesopores by covalently grafting chains with Zn open metal sites and primary amine groups as dual CO₂-philic sites. The resulting COF not only maintains a BET surface area up to 1180 m² g^-1 but also enables an ideal selectivity for CO₂/N₂ of 153 at 100 kPa, which is almost 10-fold higher than the pristine COF. Mechanistic investigations reveal that micropore filling and strong binding sites contribute to enhanced CO₂ adsorption. The pore engineering strategy reported here provides essential insights for developing the next generation of adsorbent materials.