A combinatorial approach towards water-stable metal-organic frameworks for highly efficient carbon dioxide separation

Area of Science:

• Materials Science
• Chemistry

Background:

• Metal-organic frameworks (MOFs) are porous materials with diverse applications.
• UiO-66 is a well-known zirconium-based MOF with a robust structure.
• Functionalization of MOFs is crucial for tuning their properties.

Purpose of the Study:

• To synthesize a library of UiO-66-derived MOFs with varying sulfate group content.
• To investigate the impact of sulfate functionalization on MOF properties, including water stability and CO2 adsorption.

Main Methods:

• Combinatorial synthesis involving mixed ligand copolymerization of benzene-1,4-dicarboxylic acid (BDC) and sodium 2-sulfoterephthalate (SS-BDC) with zirconium tetrachloride (ZrCl4).
• Two post-synthetic modifications (PSMs) were employed in tandem.
• Characterization of the synthesized MOFs for structural integrity, water stability across a wide pH range, and CO2 uptake capacity and selectivity.

Main Results:

• A library of 20 UiO-66-derived MOFs with the UiO-66 topology was successfully synthesized.
• The MOFs exhibited excellent water stability across a broad pH range (1-12).
• The synthesized MOFs demonstrated high CO2 uptake capacities and selectivities.

Conclusions:

• Mixed ligand copolymerization and PSMs offer an effective combinatorial approach for MOF library synthesis.
• Sulfate functionalization of UiO-66 MOFs enhances their water stability and CO2 adsorption performance.
• These functionalized MOFs hold promise for carbon capture and other gas separation applications.