Impeding Thermal Atomization Enables Synthesizing Fe₂N Cluster Liganded Single Fe-Atom Catalyst for Highly Efficient...

Area of Science:

• Materials Science
• Catalysis
• Electrochemistry

Background:

• Single-atom catalysts (SACs) offer high atom utilization efficiency.
• Ligand anchoring is crucial for tuning the electronic structure of active sites in SACs.
• Iron-based SACs are promising for oxygen reduction reactions (ORR).

Purpose of the Study:

• To develop a new strategy for synthesizing single-atom catalysts (SACs) with enhanced activity.
• To investigate the effect of Fe2N clusters as ligands on Fe-N4 active sites.
• To evaluate the performance of the novel catalyst in oxygen reduction reactions and zinc-air batteries.

Main Methods:

• Nitridation-induced-clustering strategy to synthesize Fe2N cluster-anchored Fe-N4 SACs (Fe2Nnc/Fe1-N-C).
• Electrochemical characterization of oxygen reduction reaction (ORR) activity in alkaline media.
• Fabrication and testing of Zn-air batteries using the synthesized catalysts as air cathodes.
• Density functional theory (DFT) calculations to elucidate the catalytic mechanism.

Main Results:

• The Fe2Nnc/Fe1-N-C catalysts exhibited superior ORR activity with a record half-wave potential of 0.957 V vs RHE.
• Zn-air batteries using Fe2Nnc/Fe1-N-C demonstrated a small charge-discharge gap of ~0.658 V and excellent cyclability over 1000 hours.
• DFT calculations confirmed that Fe2Nnc ligands modify the electronic structure of Fe-N4 sites, facilitating ORR kinetics.

Conclusions:

• The nitridation-induced-clustering strategy effectively produces Fe2N cluster-anchored SACs.
• The Fe2Nnc ligands significantly enhance the catalytic activity of Fe-N4 sites for ORR.
• The developed Fe2Nnc/Fe1-N-C catalysts show great potential for high-performance air cathodes in Zn-air batteries.