Dissecting the Water Uptake Behavior of Metal–Organic Frameworks Using Their Isolated Linkers and Metal Nodes

Abstract

Metal−organic frameworks (MOFs) have been a center of interest because of their highly diverse structural and physicochemical properties. The study of many MOFs requires periodic calculations. However, isolated models have also been employed in first-principles calculations to study their mechanisms and energy profiles. Following the water adsorption properties of MOF building units, this study determines how far isolated models of MOFs can reproduce experimental observations and where they fail. According to our DFT simulations of water adsorption by 70 common metal nodes and over 110 organic linkers, the isolated models provide some opportunities and limitations. They indicate the water adsorption mechanism and energy of the individual MOF components. They give clues about the water stability of the metal nodes and the degradation pathways. Also, they predict an overall trend for the maximum water uptake capacity. However, they cannot always give an accurate insight into MOF's water adsorption enthalpies, their water harvesting efficiency, their water uptake capacities under varying conditions, and a complete picture of the water uptake mechanism inside MOF pores.

Insights into Isotherm Step and Pore-Filling Mechanisms for Water Adsorption in Covalent Organic Frameworks

“…The production of water can be enhanced with the addition of a heat pump . Researchers have investigated various porous materials, such as silica gels, zeolites, metal–organic frameworks (MOFs), − and covalent organic frameworks (COFs) for their water adsorption properties. The present work explores COFs as atmospheric water harvesters (AWHs) from a molecular simulations’ perspective.…”