Highly active, ultra-low loading single-atom iron catalysts for catalytic transfer hydrogenation

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Noble metal-free catalysts are crucial for sustainable chemistry.
• Developing highly effective and selective catalysts remains a significant challenge.
• Single-atom catalysts offer unique reactivity and selectivity.

Purpose of the Study:

• To fabricate and characterize a single-atom iron catalyst using zeolitic imidazolate framework-8 (ZIF-8).
• To evaluate the catalyst's performance in catalytic transfer hydrogenation of furfural.
• To elucidate the reaction mechanism and identify the active site.

Main Methods:

• Synthesis of single-atom iron catalyst via iron adsorption onto ZIF-8 followed by pyrolysis.
• Catalytic transfer hydrogenation reactions.
• Isotopic labeling experiments for mechanistic studies.
• First principles simulations and spectroscopic analyses.

Main Results:

• The fabricated catalyst exhibits performance comparable to state-of-the-art catalysts and significantly outperforms other iron catalysts.
• An intermolecular hydride transfer mechanism was identified.
• Pyrrolic Fe(II)-plN3 was revealed as the active site, with its flexibility being critical for catalysis.
• The catalyst shows chemoselectivity for multiple substrates and a unique substrate inhibition pattern.

Conclusions:

• The developed single-atom iron catalyst is highly effective and selective for catalytic transfer hydrogenation.
• The unique structure and flexibility of the pyrrolic Fe(II)-plN3 active site are key to its performance.
• This work provides a pathway for designing advanced noble-metal-free single-atom catalysts.