Covalent organic frameworks for extremely high reversible CO2 uptake capacity: a theoretical approach

We report that the novel covalent organic frameworks (COFs) are capable of reversibly providing an extremely high uptake capacity of carbon dioxide at room temperature. These COFs are designed via the combination of ab initio calculations and force-field calculations. For this goal, we explore the adsorption sites of carbon dioxide on COFs, their porosity, as well as carbon dioxide adsorption isotherms. We identify the binding sites and energies of CO2 on COFs using ab initio calculations and obtain the carbon dioxide adsorption isotherms using grand canonical ensemble Monte Carlo calculations. Moreover, the calculated adsorption isotherms are compared with the experimental values in order to build the reference model in describing the interactions between the CO2 and the COFs and in predicting the CO2 adsorption isotherms of COFs. Finally, we design three new COFs, 2D COF-05, 3D COF-05 (ctn), and 3D COF-05 (bor), for the high capacity CO2 storage. The carbon dioxide adsorption values of the new 3D COFs are about six times larger than that of MOF-177. This suggests that 3D COFs are very promising candidates for high capacity CO2 storage.