A computational study of the effect of doping metals on CO2/CH4 separation in metal-organic frameworks

In this work, a hierarchical multiscale approach combining grand canonical Monte Carlo simulation and density functional theory calculation was performed to study the effect of doping different metal atoms on CO2/CH4 mixture separation in metal-organic frameworks (MOFs). The computational results show that the MOFs doped with alkali metals can greatly enhance the adsorption selectivity of CO2/CH4 mixture. However, this enhancement becomes weaker as the atomic number of doped metal atoms increases. In addition, this work also demonstrates that LJ potential parameters of metals should be considered combined with the electrostatic interactions, while using metal-doping strategy to improve the separation performance of MOFs. The knowledge obtained is expected to provide useful information for designing new MOFs with improved separation performance in various practical important gas mixture systems. (C) 2011 Elsevier Inc. All rights reserved.