Interrogating the Metal Identity Effect of Isostructural NU-1801 Frameworks on Toxic Gas Capture with...

Area of Science:

• Materials Science
• Environmental Chemistry
• Chemical Engineering

Background:

• Effective capture of toxic industrial chemicals (TICs) is crucial for environmental safety and waste management.
• Metal-organic frameworks (MOFs) show promise for TIC capture, but design principles require further elucidation.
• Isostructural MOFs offer a systematic platform to study structure-property relationships.

Purpose of the Study:

• To systematically investigate the impact of metal identity on the stability and adsorption performance of isostructural MOFs for TIC capture.
• To elucidate the structure-property relationships governing TIC adsorption in MOFs.
• To identify optimal MOF materials for the capture of sulfur dioxide (SO2) and ammonia (NH3) under varying conditions.

Main Methods:

• Reticular chemistry was employed to synthesize isostructural NU-1801 frameworks using different metal clusters (Y6, Zr6, Hf6, Ce6, Th6).
• Adsorption performance for TICs, including SO2 and NH3, was evaluated using breakthrough experiments.
• Molecular studies, including coadsorption analysis, were performed to understand binding mechanisms and interactions with water molecules.

Main Results:

• NU-1801(Zr) exhibited the highest structural stability and superior adsorption capacity for SO2 and NH3 among the synthesized analogs.
• NU-1801(Zr) demonstrated moisture-enhanced capture of SO2 and NH3, attributed to the formation of sulfate and ammonium species.
• Molecular studies confirmed that SO2 and NH3 bind at the metal carboxylic cluster, with μ3-OH species as key binding sites, and coadsorption with water is thermodynamically favorable.

Conclusions:

• Metal identity plays a critical role in the rational design of isostructural MOF adsorbents for effective TIC capture.
• NU-1801(Zr) is a promising material for practical SO2 and NH3 capture, particularly in the presence of moisture.
• Understanding the influence of metal clusters and water coadsorption is key to optimizing MOF performance for environmental remediation.