Judicious design functionalized 3D‐COF to enhance CO2 adsorption and separation

ABSTRACT The effects of functional groups (including OH, OCH 3 , NH 2 , CH 2 NH 2 , COOH, SO 3 H, OCO(CH 2 ) 2 COOH(E‐COOH), and (CH 2 ) 4 COOH(c‐COOH)) in 3D covalent organic frameworks (3D‐COFs) on CO 2 adsorption and separation are investigated by grand canonical Monte Carlo (GCMC) simulations and density functional theory calculations. The results indicate that interaction between CO 2 and the framework is the main factor for determining CO 2 uptakes at low pressure, while pore size becomes the decisive factor at high pressure. The binding energy of CO 2 with functionalized linker is correlated to CO 2 uptake at 0.3 bar and 298 K on 3D‐COF‐1, suggesting functional groups play a key role in CO 2 capture in microporous 3D‐COFs. Moreover, CO 2 selectivity over CH 4 , N 2 , and H 2 can be significantly enhanced by functionalization, where CH 2 NH 2 , COOH, SO 3 H, and E‐COOH enhance CO 2 adsorption more effectively at 1 bar. Among them, SO 3 H is the most promising functional group in 3D‐COFs for CO 2 separation.