Trade-Off between Adsorption and Regeneration in Functional Metal–Organic Frameworks for Atmospheric Water Harvesting: A Multiscale Modeling Approach

Understanding the trade-off between water adsorption and regeneration efficiency is essential for the rational design of functional metal-organic frameworks (MOFs) for atmospheric water harvesting (AWH). In this work, Cu-halide-functionalized MOF-303 is employed as a representative case study. A multiscale modeling framework combining Grand Canonical Monte Carlo (GCMC), Kinetic Monte Carlo (KMC), Density Functional Theory (DFT), and Molecular Dynamics (MD) simulations, along with a time-dependent thermodynamic analysis, is used to evaluate the impact of different Cu-halide ligands (F, Cl, Br, and I) on water adsorption-desorption behavior. Model accuracy is validated through comparison with previously reported experimental data from the literature for pristine MOF-303, showing good agreement between simulations and published experimental results. The results indicate that Cu-F@MOF-303 exhibits strong electrostatic interactions, leading to high water uptake and rapid adsorption kinetics, but at the expense of higher regeneration temperatures. In contrast, Cu-Cl@MOF-303 achieves a more balanced performance, offering moderate adsorption capacity with comparatively energy-efficient regeneration. Cu-Br@MOF-303 and Cu-I@MOF-303 enhance water uptake at low relative humidity (<20%) but require higher energy input for water release. Overall, this study demonstrates how targeted functionalization governs the adsorption-regeneration trade-off in MOFs and provides guidance for the sustainable design of AWH materials under diverse environmental conditions.