Multiscale model to resolve the chemical environment in a pressurized CO₂-captured solution electrolyzer

Area of Science:

• Electrochemistry
• Catalysis
• Renewable Energy

Background:

• Electrochemical CO2 reduction typically uses gaseous CO2, limiting efficiency.
• Developing alternative methods for CO2 utilization is crucial for sustainable energy.

Purpose of the Study:

• To propose and investigate a pressurized CO2-captured solution electrolyzer for solar fuel production.
• To quantitatively model the effects of pressure on CO2 reduction activity and selectivity.

Main Methods:

• Development of an experimentally validated multiscale model.
• Investigation of pressure-induced chemical environment variations.
• Utilizing a commercial silver nanoparticle catalyst.

Main Results:

• Pressure variations affect cathode pH and species coverage, influencing CO2 reduction.
• Increased pressure from 1 to 10 bar significantly enhances CO selectivity.
• Achieved >95% CO selectivity at -0.6 V vs RHE with a solar-to-CO efficiency of 16.8%.

Conclusions:

• Pressurized CO2-captured solution electrolysis is a viable alternative to gaseous CO2-fed systems.
• This approach offers superior performance for aqueous-based CO2 reduction to CO.
• Demonstrated a highly efficient solar-to-CO conversion process.