Hierarchal Porous Graphene-Structured Electrocatalysts with Fe-N₅ Active Sites Modified with Fe Clusters for Enhanced...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• The local coordination environment around active centers significantly influences M-N-C catalyst activity.
• Fe-N-C catalysts are crucial for oxygen reduction reactions (ORR).

Purpose of the Study:

• To fabricate a porous graphene catalyst with Fe-N5 active sites and Fe clusters.
• To investigate the catalyst's structure-activity relationship for ORR.
• To evaluate the catalyst's performance in zinc-air batteries.

Main Methods:

• Synthesis of porous graphene using Fe3+-SCN- and NaHCO3.
• Characterization using various techniques.
• Theoretical calculations.
• Electrochemical testing for ORR.
• Assembly and testing of a primary zinc-air battery.

Main Results:

• Successfully fabricated porous graphene with Fe-N5 active sites and Fe clusters.
• Confirmed unique Fe-N5 configuration and improved ORR activity.
• Demonstrated enhanced mass and electron transfer due to pores.
• Achieved excellent ORR activity (half-wave potential of 0.89 V), selectivity, and stability.
• Zinc-air battery achieved a maximum power density of 0.205 W/cm2.

Conclusions:

• The developed CSA-Fe-N-C catalyst exhibits superior ORR performance.
• The porous structure facilitates mass/electron transfer and exposes more active sites.
• This catalyst shows potential as a cost-effective alternative to platinum for zinc-air batteries.