Sub-5 nm Cu Clusters for Efficient CO₂-to-C₂H₄ Conversion: Synergistic Microstructure and Catalytic Microenvironment

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Electrochemical CO2 reduction (CO2RR) is key for carbon neutrality but faces challenges with hydrogen evolution in acidic media.
• Alkaline electrolytes favor multicarbon product formation, such as ethylene (C2H4), over side reactions.

Purpose of the Study:

• To fabricate and investigate surface-loaded copper cluster catalysts ( < 5 nm) for selective CO2RR to C2H4.
• To understand the synergistic effects between catalyst microstructure and microenvironment on CO2RR performance.

Main Methods:

• Fabrication of copper cluster catalysts using magnetron sputtering, inert gas condensation, and cluster beam deposition.
• Electrochemical evaluation in a flow cell using 1 M KOH electrolyte.
• Finite element simulations and in situ Raman spectroscopy for mechanistic insights.

Main Results:

• Achieved Faradaic efficiency (FE) for CO2-to-C2H4 conversion exceeding 50% over a wide current density range (50–180 mA cm-2).
• Optimized Cu cluster catalysts showed enhanced FE C2H4 and broader effective current density compared to pristine Cu/PTFE.
• Identified synergistic interactions among interfacial species (*CO, OH-, K+) through simulations and spectroscopy.

Conclusions:

• A general strategy for regulating catalytic interfaces via nanostructure design was proposed.
• This approach offers a promising route for selective CO2 conversion to ethylene.
• Advanced copper cluster catalysts significantly improve CO2RR efficiency and selectivity.