Programmable Water Sorption through Linker Installation into a Zirconium Metal-Organic Framework

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Hydrolytically stable materials with programmable water sorption are vital for on-demand water sorption systems.
• Metal-organic frameworks (MOFs) show promise as water adsorbents, but developing robust, tailorable scaffolds remains challenging.

Purpose of the Study:

• To address the need for tailorable MOF scaffolds, this study aimed to create new MOFs with precisely controlled water sorption properties.
• The research focused on enhancing structural stability and modulating water adsorption behavior through a topology-guided linker installation strategy.

Main Methods:

• A topology-guided linker installation strategy was employed using NU-600, a zirconium-based MOF (Zr-MOF) with vacant coordination sites.
• Three N-heterocyclic auxiliary linkers of varying lengths were installed into designated sites, creating six new MOFs (NU-606 to NU-611).
• The structural stability and water sorption properties of the resulting MOFs were systematically investigated.

Main Results:

• The new MOFs (NU-606 to NU-611) exhibited enhanced structural stability against channel collapse during water desorption.
• This improved stability is attributed to the increased connectivity of the Zr₆ clusters within the MOF structure.
• Systematic modulation of pore-filling pressure was achieved, reducing it from approximately 55% relative humidity (RH) for the parent NU-600 to below 40% RH in the new MOFs.

Conclusions:

• The topology-driven linker installation strategy provides precise control over MOF water sorption properties.
• This facile route enables the rational design of MOF adsorbents tailored for specific water sorption applications.
• The developed MOFs offer a promising solution for on-demand water sorption systems requiring robust and tunable materials.