Zn-MOF as a Single Catalyst with Dual Lewis Acidic and Basic Reaction Sites for CO₂ Fixation

Area of Science:

• Materials Science
• Catalysis
• Environmental Chemistry

Background:

• Rising carbon dioxide (CO2) emissions disrupt environmental balance, impacting biodiversity and human health.
• Converting CO2 into cyclic carbonates using heterogeneous catalysts like metal-organic frameworks (MOFs) is a key strategy for mitigation.
• Developing stable and efficient MOFs is crucial for effective CO2 utilization.

Purpose of the Study:

• To synthesize and characterize a novel nitrogen-rich Zn(II)-based MOF for CO2 conversion.
• To evaluate the catalytic performance of the synthesized MOF in the coupling of CO2 with epoxides.
• To assess the stability and reusability of the MOF catalyst under reaction conditions.

Main Methods:

• A mixed ligand strategy was employed to synthesize the nitrogen-rich Zn-MOF, [Zn(CPMT)(bipy)].
• The synthesized MOF was characterized for its chemical stability in acidic, basic, and organic solvent conditions.
• The catalytic activity of the MOF was tested for the cycloaddition of CO2 to epoxides under mild conditions (atmospheric pressure, 70 °C).

Main Results:

• The synthesized Zn-MOF exhibited high chemical stability.
• The MOF demonstrated excellent catalytic activity, achieving 98% yield for epichlorohydrin carbonate and 82% yield for styrene carbonate.
• The catalyst maintained its structural integrity and activity over seven reuse cycles, with high turnover numbers (TON) of 217 and 181.

Conclusions:

• A novel, stable, and highly efficient nitrogen-rich Zn-MOF has been successfully synthesized.
• This MOF serves as an effective heterogeneous catalyst for the cycloaddition of CO2 to epoxides, offering high yields and reusability.
• The findings present a promising pathway for sustainable CO2 utilization and the production of cyclic carbonates.