Structure–property relationships of porous materials for carbon dioxide separation and capture

Abstract

There is an urgent need to identify porous materials that can efficiently separate CO₂ from mixtures of gases, such as the exhaust of fossil-fuel-based power plants and from impure sources of CH₄ (e.g., natural gas and landfill gas). Recently, researchers have investigated collections of porous metal–organic frameworks (MOFs) with the intent of finding correlations between CO₂ separation ability and various material properties. However, due to the limited size of the collections, no clear correlations were found for material properties such as pore size, surface area, and pore volume, leaving researchers with little guidance in the design of new materials. In this work we drastically expand the scope of previous studies to include over 130 000 hypothetical MOFs, using molecular simulation to generate the adsorption properties. The resulting data exhibit sharply defined structure–property relationships that were not apparent when smaller collections of MOFs were considered. We show clear correlations between purely structural characteristics (e.g., pore size, surface area, and pore volume), as well as chemical characteristics (i.e., functional groups), with five adsorbent evaluation criteria taken from the engineering literature. These reported structure–property relationships can serve as a map for experimental synthesis going forward.