Solar-Driven Nitrogen Fixation Catalyzed by Stable Radical-Containing MOFs: Improved Efficiency Induced by a...

Area of Science:

• Materials Science
• Chemistry
• Catalysis

Background:

• Radical-containing metal-organic frameworks (RMOFs) offer unique electronic properties.
• Developing stable and efficient RMOFs for catalytic applications is crucial.

Purpose of the Study:

• To synthesize and characterize a new viologen-based RMOF, Gd-IHEP-7.
• To investigate its transformation into another RMOF, Gd-IHEP-8.
• To evaluate their performance in solar-driven nitrogen fixation.

Main Methods:

• Single-crystal X-ray diffraction for structural analysis.
• Spectroscopic techniques for characterization.
• Solar-driven nitrogen fixation experiments.
• Theoretical calculations for mechanistic insights.

Main Results:

• Gd-IHEP-7 was synthesized and transformed into Gd-IHEP-8 via a single-crystal-to-single-crystal process.
• Both RMOFs demonstrated excellent air and water stability.
• Ammonia production rates of 128 and 220 μmol h⁻¹ g⁻¹ were achieved for Gd-IHEP-7 and Gd-IHEP-8, respectively.
• Enhanced catalytic efficiency in Gd-IHEP-8 was linked to stabilized intermediates via hydrogen bonding.

Conclusions:

• Viologen-based RMOFs show promise for solar energy applications.
• The single-crystal-to-single-crystal transformation can enhance catalytic properties.
• Hydrogen bonding plays a key role in stabilizing intermediates for improved nitrogen fixation.