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

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.