Modulating Oxygen Reduction Activity in Chalcogenophene-Incorporated Organic Electrocatalysts through Main-Group...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Organic small molecules (OSMs) are vital for fuel cell cathode catalysts.
• Heteroatom doping can improve metal-free carbon catalysts, but structure-activity relationships are unclear.
• A consistent molecular skeleton is needed to study doping effects.

Purpose of the Study:

• To investigate how introducing different chalcogens into the same OSM skeleton affects catalytic activity.
• To develop high-performance, metal-free electrocatalysts for fuel cells.
• To elucidate the mechanism of enhanced oxygen reduction reaction (ORR) activity.

Main Methods:

• Main-group engineering to introduce chalcogens (e.g., Se) into OSMs.
• Fabrication of catalysts using OSMs and carbonized calcium alginate.
• Electrochemical characterization of ORR performance (half-wave potential, stability).
• Density Functional Theory (DFT) calculations to understand reaction mechanisms.

Main Results:

• Se-containing OSM (OSM-Se) with carbonized calcium alginate showed a quasi-four-electron ORR pathway.
• Achieved a superior half-wave potential (E1/2) of 0.73 V and excellent electrochemical stability.
• DFT calculations confirmed enhanced oxygen adsorption/dissociation and reduced ORR barrier by Se.

Conclusions:

• Modulating charge distribution via chalcogen doping in OSMs is an effective strategy for metal-free electrocatalysts.
• Se-containing OSMs show significant promise for efficient and stable oxygen reduction reactions in fuel cells.
• This work provides a simple yet powerful method for designing advanced OSM-based electrocatalysts.