Single-Atom Co-N₄ Electrocatalyst Enabling Four-Electron Oxygen Reduction with Enhanced Hydrogen Peroxide Tolerance...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalysis of the oxygen reduction reaction (ORR) is crucial for energy technologies and monitoring.
• Hydrogen peroxide (H2O2) byproduct formation reduces selectivity in many ORR catalysts.
• Developing selective and robust ORR electrocatalysts is essential for practical applications.

Purpose of the Study:

• To develop a single-atom electrocatalyst for highly selective four-electron ORR in neutral media.
• To investigate the catalyst's performance and tolerance to hydrogen peroxide.
• To understand the catalytic mechanism and metal-adsorbate interactions.

Main Methods:

• Synthesis and characterization of a single-atom Co-N4 electrocatalyst.
• Electrochemical measurements including cyclic voltammetry and rotating disk electrode techniques.
• Electrochemical kinetic analysis and Density Functional Theory (DFT) calculations.

Main Results:

• The Co-N4 catalyst achieved a four-electron ORR with an onset potential of 0.68 V in neutral media.
• The catalyst exhibited high tolerance to H2O2, outperforming commercial Pt catalysts.
• DFT calculations indicated weak H2O2 adsorption on Co centers, suppressing its reduction.
• Demonstrated reliable in vivo oxygen sensing performance with high selectivity.

Conclusions:

• Single-atom Co-N4 catalysts can effectively promote the direct four-electron ORR pathway.
• Tailoring metal-adsorbate interactions is key to achieving high selectivity and H2O2 tolerance.
• This catalyst shows significant potential for selective oxygen monitoring and other applications.