Comparing electrocatalytic and chemical oxygen reduction reaction by a molecular copper complex

Area of Science:

• Bioinorganic Chemistry
• Electrochemistry
• Catalysis

Background:

• The CuB site in cytochrome c oxidase (CcO) is crucial for oxygen reduction.
• Mimicking metalloenzyme active sites can lead to novel catalysts.

Purpose of the Study:

• To design and synthesize a molecular copper complex inspired by the CcO CuB site.
• To investigate the oxygen reduction reaction (ORR) activity of this complex.
• To elucidate the reaction mechanisms of the chemical and electrocatalytic ORR.

Main Methods:

• Synthesis of a molecular Cu(II) complex with a mixed pyridine-phenol ligand.
• Electrocatalytic and chemical oxygen reduction reactions.
• Kinetic analysis of reaction pathways.

Main Results:

• The synthesized Cu(II) complex (1) effectively catalyzes the 4e-/4H+ reduction of O2.
• Distinct reaction mechanisms were identified for chemical and electrocatalytic ORR.
• The ligand backbone plays a critical role in the ORR process.

Conclusions:

• The designed copper complex serves as an effective biomimetic catalyst for ORR.
• Understanding the mechanistic differences is key to optimizing ORR catalysts.
• Ligand design is crucial for controlling the activity and selectivity of copper-based ORR catalysts.