Linker Functionalization Strategy for Water Adsorption in Metal-Organic Frameworks

Area of Science:

• Materials Science
• Chemistry
• Environmental Science

Background:

• Water adsorption in metal-organic frameworks (MOFs) is crucial for water capture technologies.
• Functionalizing organic linkers can tune MOF hydrophilicity and water uptake.
• Understanding these interactions is key to designing advanced water harvesting materials.

Purpose of the Study:

• To screen functional groups for optimal water affinity in MOFs.
• To investigate the impact of functionalization on water adsorption isotherms and uptake.
• To identify high-performance MOFs for water harvesting applications.

Main Methods:

• Ab initio calculations were used to screen functional groups for water affinity.
• Binding energies were calculated using RI-MP2/def2-TZVPP level of theory.
• Monte Carlo simulations assessed water uptake in functionalized MOF-74-III.

Main Results:

• Functional groups forming two hydrogen bonds with water exhibited highest affinities.
• The -OSO3H group showed a binding energy of -12.7 Kcal/mol.
• Functionalized MOF-74-III enhanced water uptake up to 30% relative humidity.
• Saturation water uptake exceeded 800 cm3/cm3 for all functionalized candidates.

Conclusions:

• Specific functional groups can significantly improve MOF hydrophilicity and water adsorption.
• Functionalized MOF-74-III materials demonstrate excellent potential for water harvesting.
• These findings position MOFs as leading candidates for efficient atmospheric water capture.