Promoted O₂ Activation at a Co^III Center for Significantly Improved Electrocatalytic Oxygen Reduction Reaction

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Efficient electrocatalytic oxygen reduction reaction (ORR) is crucial for energy conversion devices.
• Activating O₂ typically requires low-valent metal ions, often at high cathodic potentials.

Purpose of the Study:

• To develop a novel catalyst for enhanced O₂ activation and ORR electrocatalysis.
• To investigate the effect of Sc³⁺ coordination on cobalt corrole performance.

Main Methods:

• Synthesis of a Sc³⁺-hung Co^III corrole (compound 1) with a crown ether substituent.
• Electrochemical evaluation of the catalyst in acetonitrile and sulfuric acid solutions.
• Analysis of ORR performance, including overpotential and half-wave potential.

Main Results:

• The Sc³⁺-hung Co^III corrole significantly reduced ORR overpotential by 1.0 V (acetonitrile) and 170 mV (0.5 M H₂SO₄).
• Achieved a high ORR half-wave potential of 0.78 V vs RHE in 0.5 M H₂SO₄ with a 3.87 electron transfer number.
• Demonstrated Sc³⁺ promotion of O₂ binding and activation at the Co^III center.

Conclusions:

• The Sc³⁺-hung corrole effectively promotes O₂ activation and O-O bond cleavage.
• This catalyst design offers a promising strategy for efficient electrocatalytic oxygen reduction.