Constructing N,S and N,P Co-Coordination in Fe Single-Atom Catalyst for High-Performance Oxygen Redox Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Single-atom catalysts (SACs) are crucial for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER).
• The coordination environment of the central metal atom critically influences SACs' activity.
• Iron-nitrogen (FeN4) coordination is a common motif in highly active SACs.

Purpose of the Study:

• To investigate the impact of introducing sulfur (S) or phosphorus (P) into the FeN4 coordination sphere on the electronic structure and catalytic performance of iron-based SACs.
• To explore novel FeSNx and FePNx single-atom catalysts for enhanced ORR and OER activity.

Main Methods:

• Computational investigation of FeSxN4-x and FePxN4-x (x=1-4) coordination environments.
• Electrochemical testing of synthesized catalysts for ORR and OER performance.
• Analysis of electronic structure and catalytic mechanisms.

Main Results:

• FePN3 demonstrated excellent ORR activity with a low overpotential of 0.29 V, surpassing FeN4.
• FeSN3 exhibited superior OER activity with an overpotential of 0.68 V, outperforming FeN4.
• Both FePN3 and FeSN3 catalysts displayed remarkable thermodynamic and electrochemical stability.

Conclusions:

• Co-coordination of N, P, and S atoms in SACs provides an optimized catalytic environment compared to pure N coordination.
• FePN3 and FeSN3 represent high-performance electrocatalysts for ORR and OER, respectively.
• Tuning the coordination environment through N, P, and S co-doping is an effective strategy for designing advanced single-atom catalysts.