Atomic Cu Sites Engineering Enables Efficient CO₂ Electroreduction to Methane with High CH₄/C₂H₄ Ratio

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Copper-based catalysts show promise for CO2 capture and utilization via electrochemical reduction.
• Mobility and accessibility of active sites in Cu catalysts limit their efficiency for CO2 electrochemical reduction reaction (CO2RR).

Purpose of the Study:

• To engineer accessible and structurally stable single copper (Cu) sites within graphitic carbon nitride (g-C3N4) for enhanced CO2-to-CH4 conversion.
• To investigate the effect of Cu site coordination and density on CO2RR performance.

Main Methods:

• Incorporation of single atomic Cu into nitrogen cavities of g-C3N4.
• Tuning the coordination and density of Cu sites within the g-C3N4 matrix.
• Electrochemical reduction of CO2 to evaluate methane production.

Main Results:

• An optimal catalyst with one Cu atom per nitrogen cavity achieved a maximum CH4 Faraday efficiency of 49.04%.
• The catalyst demonstrated a high CH4/C2H4 product ratio exceeding 9.
• The single Cu atom catalyst in g-C3N4 exhibited enhanced stability and selectivity for CO2RR.

Conclusions:

• This work presents the first experimental study of g-C3N4-supported single Cu atom catalysts for efficient CO2-to-CH4 production.
• Engineering Cu active sites within 2D materials with porous structures offers a principle for designing stable and selective catalysts for CO2RR.