CO₂-to-CO Conversion with Over 10 % Efficiency Using Earth Abundant System in a Single-Compartment Reactor with...

Area of Science:

• Electrochemistry
• Materials Science
• Photocatalysis

Background:

• Direct conversion of carbon dioxide (CO2) to valuable chemicals using solar energy is a key goal for sustainable technology.
• Conventional methods often require ion-exchange membranes to separate oxygen produced at the anode, increasing complexity and cost.
• Oxygen byproduct can deactivate catalysts used in CO2 reduction.

Purpose of the Study:

• To demonstrate a cost-effective, solar-driven CO2 reduction to CO with high efficiency.
• To develop a single-compartment reactor system that avoids ion-exchange membranes.
• To utilize a manganese (Mn) complex catalyst that maintains activity in the presence of oxygen.

Main Methods:

• Employed a single-compartment reactor with a manganese (Mn) complex cathode and an iron-nickel (Fe-Ni) anode.
• Integrated a silicon (Si) solar cell to power the electrochemical conversion.
• Utilized operando surface-enhanced Raman spectroscopy (SERS) to investigate catalyst-CO2 and catalyst-O2 interactions.

Main Results:

• Achieved a solar-to-CO conversion efficiency exceeding 10%.
• The Mn complex catalyst demonstrated stability and activity in the presence of 15% oxygen.
• SERS analysis confirmed the Mn catalyst preferentially reacts with CO2, not adsorbing O2, enabling single-compartment operation.

Conclusions:

• The developed Mn complex catalyst enables efficient solar-driven CO2 to CO conversion in a membrane-free, single-compartment reactor.
• This approach offers a potentially more cost-effective and simpler alternative to existing CO2 reduction technologies.
• The catalyst's unique selectivity against oxygen adsorption is crucial for its performance in the presence of O2 byproduct.