How does the pore morphology influence the adsorption performance of metal-organic frameworks? A molecular simulation study of methane and ethane adsorption in Zn-MOFs

摘要

Porous metal-organic frameworks (MOFs) have recently gained much attention as promising materials for gas adsorption. These materials are synthesised in a self-assembly process in which metal vertices are interconnected by organic linkers. As a result of this building block approach, these materials offer the possibility to tune host / guest interactions and therefore to tailor them rationally for specific adsorption applications. In this paper, molecular simulations are used to study methane and ethane adsorption in Zn-dicarboxylate MOFs with different pore morphologies. A careful analysis of the sorbate / framework interactions revealed that one-dimensional pores with sharp edges are beneficial for gas storage and separation at low pressure. Yet, because of the limited volume of the energetically preferable corner regions, this effect is much less pronounced at higher pressure.