Metal–Organic Frameworks Grafted by Univariate and Multivariate Heterocycles for Enhancing CO₂ Capture: A Molecular Simulation Study

The metal–organic frameworks (MOFs) comprising heterocyclic ligands show great potential in terms of CO2 capture. In this work, a series of heterocycles characterized by N, O, and S elements were screened through comparing CO2/heterocycle binding energies calculated by an ab initio method. Thiophene, furan, and triazole were finally selected, and the corresponding CO2 interaction energy decompositions were further analyzed using symmetry-adapted perturbation theory (SAPT). The selected heterocycles were grafted to UiO-67, and then grand canonical Monte Carlo (GCMC) simulations were systematically carried out to evaluate their contributions on CO2 adsorption properties of MOFs. The force field parameters for heteroatoms were obtained by a quantum mechanical method. Among these three heterocycle-grafted MOFs, triazole@UiO-67 shows the best performance in the CO2 adsorption process and the volumetric uptake amount is over 4 times higher than that of the original UiO-67 at 298 K and 100 kPa. This can be mainl...