A bio-inspired O₂-tolerant catalytic CO₂ reduction electrode.

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Electrochemical reduction of carbon dioxide (CO2) offers a pathway for waste gas valorization.
• Oxygen (O2) presence inhibits CO2 reduction due to O2's favored thermodynamic reduction potential.

Purpose of the Study:

• To develop an oxygen-tolerant electrode for efficient CO2 electrochemical reduction to CO.
• To enable direct utilization of flue gases and captured CO2 containing oxygen.

Main Methods:

• Fabrication of a hybrid electrode using heterogenized cobalt phthalocyanine catalyst and a CO2-selective polymer layer.
• Integration of the electrode into a flow electrolytic cell for gas conversion.
• Electrochemical testing under varying O2 concentrations in the CO2 feed.

Main Results:

• The electrode achieved high Faradaic efficiency (>95%) for CO2 to CO reduction.
• Demonstrated CO2/O2 selectivity of approximately 20.
• Achieved 75.9% FECO at 27.3 mA/cm2 with 5% O2 in CO2 feed.
• Maintained 49.7% FECO with up to 20% O2.
• Exhibited stable operation for 18 hours.

Conclusions:

• The developed O2-tolerant electrode enables efficient and selective electrochemical CO2 reduction in the presence of oxygen.
• This technology holds promise for direct valorization of industrial exhaust gases.
• Further performance enhancements are possible through ligand modification of the phthalocyanine catalyst.