Bioinspired Transition-Metal Complexes as Electrocatalysts for the Oxygen Reduction Reaction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• The oxygen reduction reaction (ORR) is vital for biological processes and energy conversion devices like fuel cells and metal-air batteries.
• Developing efficient and cost-effective ORR electrocatalysts is essential to address global warming and energy demands.
• Bioinspired catalysts mimicking natural enzymes (heme and multicopper) are actively researched.

Purpose of the Study:

• To review recent advancements in non-precious metal electrocatalysts for the ORR.
• To highlight bioinspired molecular catalyst designs that avoid pyrolysis.
• To focus on iron/cobalt macrocycles and copper complexes for ORR applications.

Main Methods:

• Exploration of iron and copper-based transition-metal complexes.
• Investigation of ligand variation/substitution to tune ORR activity.
• Analysis of catalyst immobilization techniques and supporting materials.

Main Results:

• Non-precious metal electrocatalysts, particularly iron/cobalt macrocycles and copper complexes, show significant ORR activity.
• Catalyst performance is effectively tuned through ligand design, immobilization strategies, and substrate materials.
• Pyrolysis-free catalyst preparation aligns with bioinspired molecular design principles.

Conclusions:

• Bioinspired iron and copper complexes represent a promising avenue for developing high-performance, non-precious metal ORR electrocatalysts.
• Further research into ligand tuning, immobilization, and material supports will enhance catalyst efficiency.
• These catalysts hold potential for next-generation energy conversion and storage technologies.