Well-Defined Cu Precatalysts Indicate Design Rules for Reactivity in Nitrate Electroreduction.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical nitrate reduction reaction (NO3RR) to ammonia (NH3) offers a sustainable synthesis route.
• Copper (Cu)-based materials are leading catalysts for NO3RR but undergo structural changes.
• Understanding precatalyst features and their evolution is crucial for improving Cu catalyst design.

Purpose of the Study:

• To investigate the relationship between Cu precatalyst features (size, shape, oxide content) and their structural evolution during NO3RR.
• To correlate these structural dynamics with catalytic performance, specifically NH3 selectivity and production rate.
• To establish design rules for advanced Cu catalysts in NO3RR.

Main Methods:

• Utilized well-defined Cu and Cu oxide nanocrystals (NCs) as precatalysts.
• Analyzed structural evolution under NO3RR conditions.
• Evaluated catalytic performance, focusing on NH3 selectivity and production rates.

Main Results:

• Precatalyst size, shape, and oxide content significantly influence structural evolution and catalytic behavior.
• Higher oxide content, an optimized {111}/{100} facet ratio, and grain boundaries enhance NH3 selectivity.
• 10 nm Cu spheres demonstrated competitive NH3 production rates by integrating these key features.

Conclusions:

• Cu precatalyst morphology and composition dictate in situ structural evolution and NO3RR performance.
• Optimized facet ratios and grain boundaries are critical for high NH3 selectivity.
• This study provides insights into Cu catalyst morphological dynamics for improved NO3RR catalyst design.