Atomically Dispersed Metal Catalysts for Oxygen Reduction Reaction: Two-Electron vs. Four-Electron Pathways

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Developing efficient electrochemical devices like fuel cells (FCs) and metal-air batteries (MABs) necessitates optimized oxygen reduction reaction (ORR) catalysts.
• Reducing reliance on expensive noble metals is crucial for cost-effective and sustainable energy technologies.
• Atomically dispersed metal catalysts (ADMCs) present a promising avenue due to their high atom utilization and tunable properties.

Purpose of the Study:

• To summarize current research trends and reaction mechanisms in ORR catalysis.
• To elucidate the design principles for transitioning from two-electron (2e-) to four-electron (4e-) ORR catalysts.
• To review recent advancements in ADMCs for efficient 4e- ORR applications.

Main Methods:

• Literature review of ORR mechanisms and catalyst design strategies.
• Analysis of geometric and chemical coordination effects on catalyst performance.
• Documentation of recent progress in ADMC research, including M-N-C coordination, heteroatom doping, and dual-atom systems.

Main Results:

• ADMCs demonstrate high intrinsic activity and controllable coordination environments, making them viable alternatives to noble metals.
• Advances in ADMC design focus on M-N-C coordination, heteroatom doping, dual-metal systems, and NP/NC-ADM interactions for enhanced 4e- ORR.
• Understanding the evolution from 2e- to 4e- ORR pathways is key for catalyst development.

Conclusions:

• ADMCs are pivotal for developing efficient, low-cost catalysts for ORR in electrochemical devices.
• Future research should focus on optimizing ADMC design for superior 4e- ORR activity and stability.
• Addressing challenges and exploring new opportunities in ADMC development will drive progress in energy conversion technologies.