Integrating Molecular Simulations with Machine Learning Guides in the Design and Synthesis of [BMIM][BF(4)]/MOF Composites for CO(2)/N(2) Separation

[Image: see text] Considering the existence of a large number and variety of metal–organic frameworks (MOFs) and ionic liquids (ILs), assessing the gas separation potential of all possible IL/MOF composites by purely experimental methods is not practical. In this work, we combined molecular simulations and machine learning (ML) algorithms to computationally design an IL/MOF composite. Molecular simulations were first performed to screen approximately 1000 different composites of 1-n-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF(4)]) with a large variety of MOFs for CO(2) and N(2) adsorption. The results of simulations were used to develop ML models that can accurately predict the adsorption and separation performances of [BMIM][BF(4)]/MOF composites. The most important features that affect the CO(2)/N(2) selectivity of composites were extracted from ML and utilized to computationally generate an IL/MOF composite, [BMIM][BF(4)]/UiO-66, which was not present in the original material data set. This composite was finally synthesized, characterized, and tested for CO(2)/N(2) separation. Experimentally measured CO(2)/N(2) selectivity of the [BMIM][BF(4)]/UiO-66 composite matched well with the selectivity predicted by the ML model, and it was found to be comparable, if not higher than that of all previously synthesized [BMIM][BF(4)]/MOF composites reported in the literature. Our proposed approach of combining molecular simulations with ML models will be highly useful to accurately predict the CO(2)/N(2) separation performances of any [BMIM][BF(4)]/MOF composite within seconds compared to the extensive time and effort requirements of purely experimental methods.