A Universal Approach to Construct Surface-Enriched Metal-Nitrogen Sites in Carbon Matrix toward Oxygen Reduction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Metal-nitrogen (M-N) moieties are key active sites in metal-nitrogen codoped carbon (M-N/C) catalysts for the oxygen reduction reaction (ORR).
• Controlling M-N site construction and their interface exposure is crucial for efficient ORR electrocatalysis.

Purpose of the Study:

• To develop a universal synthesis strategy for surface-enriched, highly dispersed M-N sites in M-N/C catalysts.
• To investigate the ORR performance of M-N/C catalysts with various metal centers.

Main Methods:

• A prefabricated pyridine-nitrogen-rich carbon matrix was used to anchor metal ions from metal chloride vapors.
• Synthesized M-N/C catalysts (Co, Fe, Cu, Ni, Mn, Bi) were tested for ORR activity and stability in KOH solution.

Main Results:

• All synthesized M-N/C catalysts exhibited outstanding ORR activity and long-term stability.
• The optimized Co-N/C catalyst achieved a high ORR half-wave potential (E1/2) of 0.900 V vs RHE.
• The Co-N/C catalyst showed only a 6% current loss after 16 hours of testing.

Conclusions:

• The developed synthesis strategy enables the fabrication of high-performance M-N/C catalysts with diverse metal centers.
• This approach offers new possibilities for designing advanced catalysts for ORR and other applications.