Transition metal docking in MOF-303 for enhanced Atmospheric Water Harvesting: a multiscale simulation approach

Abstract

We present a multiscale computational study on water adsorption and transport in pristine and metal-functionalized MOF-303 frameworks for Atmospheric Water Harvesting (AWH). Using Grand Canonical Monte Carlo (GCMC), Kinetic Monte Carlo (KMC), and Molecular Dynamics (MD) simulations, we evaluated the thermodynamic uptake, adsorption kinetics, and mobility of water under varying humidity. Post-synthetic metalation with Cu(I) and Ag(I) increased the hydrophilicity of the framework, with Cu@MOF-303 and Ag@MOF-303 achieving a 37 % and 27 % higher uptake and faster saturation kinetics, respectively. Density Functional Theory (DFT) calculations revealed enhanced binding energies and localized polarization effects at Cu sites, supported by electrostatic potential maps and charge redistribution analyses. Radial distribution function (RDF) analyses revealed that metalation, especially with Cu, enhances water structuring near specific adsorption sites through localized polarization and extended electronic redistribution. Reduced water diffusion in Cu@MOF-303, observed via mean square displacement (MSD) profiles, confirmed stronger confinement. Additionally, temperature-dependent desorption analyses indicated that Ag@MOF-303 offers a more favorable balance between high uptake and moderate regeneration temperatures, reinforcing its practical viability under solar-driven AWH conditions. These results underscore the potential of targeted metal docking to fine-tune MOF performance for water harvesting in low-humidity and off-grid environments.