Large-scale computational assembly of ionic liquid/MOF composites: synergistic effect in the wire-tube conformation for efficient CO2/CH4 separation

Ionic liquid/metal-organic framework (IL/MOF) composites show great potential in CO2 capture. Here, we report a large-scale computational assembly of 550,357 IL/MOF composites for CO2/CH4 separation by developing a configurational-bias Monte Carlo (CBMC)-based incorporation method rather than applying the long-time Molecular Dynamics (MD) method. The introduction of ILs into MOFs shows both improvement and well balance of selectivity and working capacity. The results show that the high performing IL/MOF composites are mainly the wire-tube type structures originated from 1,3-dimethyl-imidazolium tetrafluoroborate [MMIM][BF4] and MOFs in sql topology with pore size of ~9 A, in which ILs are well confined in the MOFs to form the continuous, cation-anion alternately connected electronic nanowires. This work finds that synergistic adsorption sites can be formed in this wire-tube structure with suitable size, providing useful information that can guide the future design of IL/MOF composites with improved CO2 capture performance.