Pressure dependence in aqueous-based electrochemical CO₂ reduction.

Area of Science:

• Catalysis
• Electrochemistry
• Sustainable Chemistry

Background:

• Electrochemical CO2 reduction (CO2R) is crucial for carbon cycle management.
• Current CO2R research primarily uses ambient pressure CO2.
• Industrial CO2 is often pressurized and dissolved, differing from lab conditions.

Purpose of the Study:

• Investigate the impact of pressurized CO2 on CO2R pathways.
• Understand the mechanism behind pressure-induced selectivity changes.
• Develop strategies to optimize CO2R for industrial feedstocks.

Main Methods:

• Operando Raman spectroscopy adapted for high-pressure conditions.
• Electrochemical experiments with CO2 at pressures up to 50 bar.
• Computational modeling to validate experimental observations.

Main Results:

• Pressurization to 50 bar significantly steers CO2R towards formate production across various catalysts.
• High formate selectivity is linked to increased CO2 coverage on the cathode surface.
• Surface functionalization with a proton-resistant layer further enhances pressure-mediated selectivity.

Conclusions:

• Pressurized CO2 is a viable feedstock for selective formate production.
• Understanding CO2 coverage under pressure is key to controlling CO2R selectivity.
• This research bridges the gap between lab-scale CO2R and industrial applications.