Direct electrochemical CO₂ conversion using oxygen-mixed gas on a Cu network cathode and tailored anode

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Electrochemical CO2 reduction (eCO2R) is a promising technology for converting CO2 into valuable chemicals.
• Current eCO2R methods often require pure CO2, limiting practical applications.
• The presence of impurities like O2 can significantly hinder catalyst performance.

Purpose of the Study:

• To demonstrate effective eCO2R using a mixed gas containing 60% CO2 and 40% air.
• To develop a robust cathode catalyst capable of withstanding impurities.
• To achieve high selectivity and current density for valuable C2+ chemical production.

Main Methods:

• Fabrication of a porous copper network cathode on a hydrophobic gas diffusion layer (Cu/P-GDL).
• Testing the Cu/P-GDL cathode's performance in eCO2R using a mixed CO2/air gas feed.
• Comparison with a conventional copper cathode on a standard carbon gas diffusion layer (Cu/C-GDL).
• Optimization of the electrolyzer anode configuration for enhanced performance.

Main Results:

• The Cu/P-GDL cathode achieved a remarkable 85% faradaic efficiency for C2+ chemical production from the mixed gas.
• The conventional Cu/C-GDL cathode showed no eCO2R activity or H2 production under the same conditions.
• The optimized electrolyzer with Cu/P-GDL reached a partial current density of 132 mA cm-2 for C2+ chemicals, even with 12% O2 present.

Conclusions:

• A novel Cu/P-GDL cathode enables efficient electrochemical CO2 reduction using impure CO2 gas.
• This technology overcomes the limitations of pure CO2 requirements, broadening the scope of eCO2R applications.
• The demonstrated tolerance to oxygen opens new avenues for industrial CO2 utilization.