Water adsorption in ideal and defective UiO-66 structures

We combine experiments and simulations to study the adsorption of water in several UiO-66 frameworks (ideal and defect-containing structures). We propose a new set of charges for the frameworks that accurately provides the water-structure interaction at the molecular level. The new set is suitable for predicting water adsorption in the ideal UiO-66 structure, providing for the first time, good agreement between experimental and calculated isotherms. The proposed procedure for tuning the point charges of the framework to achieve agreement with experiments is universal and can easily be extended to other MOFs. We explore the structural characteristics in terms of adsorption of water and the potential application of these materials to water harvesting from air. Our results show that the number of introduced defects significantly affect water sorption properties, which results in shifting steep water uptake and increasing saturation loading. Additional performed experiments, such as Ar sorption and the use of the QE-TPDA method allow for a broad characterization of structure-containing defects and the impact that these defects exert on the properties of the materials.

Automated summary

In this study, we used a combination of experiments and simulations to investigate the adsorption of water in various UiO-66 frameworks. We proposed a new set of charges for the frameworks that accurately predicted the water-structure interaction at the molecular level. Our findings show that the number of defects in the frameworks significantly affects the water sorption properties. The results also suggest potential applications of these materials in water harvesting from air.