Rational design of lanthanide-based metal-organic frameworks for CO2 capture using computational modeling.

Abstract

Metal organic frameworks (MOFs) have emerged as promising materials in the context of CO₂ capture and separation. Thanks to their tunable nature, various functionalities can be introduced to improve their separation performances. Lanthanide MOFs (Ln-MOFs) with high coordination numbers offer a promising space for the design of new high-performing and stable adsorbents for gas adsorption and separation. In this study, we combined molecular simulations with quantum mechanical (QM) calculations for designing new hypothetical materials offering superior CO₂/N₂ separation performances. An Ln-MOF having high CO₂/N₂ selectivity and working capacity was originally selected and its linkers were exchanged with five different types of linkers and its metal atom was exchanged with 12 different Ln³⁺ metals to generate 77 different types of hypothetic Ln-MOFs. Following the initial geometry optimizations at the molecular mechanics (MM) level, these structures were studied for CO₂/N₂ separation by performing grand canonical Monte Carlo (GCMC) simulations. Five MOFs were found to outperform the original Ln-MOF structure and they were optimized at the QM level to obtain geometries with minimized total energy, which finally led to two hypothetic Ln-MOFs offering superior CO₂/N₂ separation performance. The computational work that we described in this study will be useful for the rational design of new Ln-based MOFs with improved CO₂ separation properties.