NH₃ Electrosynthesis from N₂ Molecules: Progresses, Challenges, and Future Perspectives.

Area of Science:

• Electrochemistry and Catalysis
• Sustainable Energy and Green Chemistry

Background:

• Green ammonia (NH3) is a vital carbon-free fuel and platform molecule produced using renewable electricity.
• Current NH3 electrosynthesis suffers from low yield and efficiency, hindering its widespread adoption.
• The complexity of NH3 synthesis involves multidisciplinary fields like electrochemistry, catalysis, and process engineering.

Purpose of the Study:

• To decouple the overlapping issues in NH3 electrosynthesis.
• To provide guidelines for future development directions in the field.
• To offer an in-depth understanding of bottleneck issues and strategies for efficient NH3 synthesis systems.

Main Methods:

• Introduced a classification scheme for NH3 electrosynthesis: direct (N2 reduction reaction) and indirect (Li-mediated/plasma-enabled).
• Decoupled complex reaction pathways to identify rate-determining steps and bottleneck issues (e.g., N2 activation, H2 evolution).
• Reviewed recent progress across the electrochemical system: electrocatalysts, electrodes, electrolytes, and electrolyzers.

Main Results:

• The classification scheme effectively separates direct and indirect NH3 electrosynthesis pathways.
• Identified key challenges including N2 activation, H2 evolution side reactions, and interface engineering.
• Highlighted advancements in materials and system design for improved NH3 production efficiency.

Conclusions:

• Addressing specific bottlenecks in N2 activation and H2 suppression is crucial for enhancing NH3 electrosynthesis.
• A multiscale perspective (atomistic to macroscale) is essential for designing efficient NH3 synthesis systems.
• This work provides a framework for future research focused on optimizing green ammonia production.