Self-supporting oxygen reduction electrocatalysts made from a nitrogen-rich network polymer

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Development of efficient and cost-effective catalysts is crucial for electrochemical applications.
• Non-precious metal catalysts are highly sought after as alternatives to platinum-group metals.
• Network polymers offer unique structural and chemical properties for catalyst design.

Purpose of the Study:

• To synthesize and evaluate a novel nitrogen-rich network polymer as a non-precious metal catalyst.
• To investigate the oxygen reduction reaction (ORR) activity of a Co-/Fe-coordinating pyrolyzed polymer.
• To assess the performance of the developed catalyst in a microbial fuel cell (MFC).

Main Methods:

• Synthesis of a nitrogen-rich network polymer using 2,6-diaminopyridine as a monomer.
• Pyrolysis of the polymer to create metal-coordination sites.
• Electrochemical evaluation of the catalyst for oxygen reduction reaction (ORR) in neutral media.
• Fabrication and testing of a microbial fuel cell (MFC) with the catalyst at the cathode.

Main Results:

• The Co-/Fe-coordinating pyrolyzed polymer demonstrated high specific oxygen reduction activity (onset potential: 0.87 V vs RHE, half-wave potential: 0.76 V vs RHE).
• The catalyst showed no crossover effect of organics on its activity in neutral media.
• An MFC equipped with this catalyst achieved more than double the power output compared to a commercial 20 wt % Pt/C catalyst.

Conclusions:

• The developed nitrogen-rich network polymer is a highly effective non-precious metal catalyst for ORR.
• This novel catalyst offers a promising, cost-effective alternative to platinum for applications like microbial fuel cells.
• The unique structure of the polymer provides abundant metal-coordination sites, enhancing catalytic activity and stability.