Ampere-level CO₂ electroreduction with single-pass conversion exceeding 85% in acid over silver penetration...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Valorization of carbon dioxide (CO₂) via electroreduction is crucial for mitigating carbonation and producing valuable chemicals.
• Suppressing the competing hydrogen evolution reaction (HER) in acidic media remains a significant challenge for CO₂ electroreduction.

Purpose of the Study:

• To develop a novel electrode for efficient CO₂ electroreduction to CO in strong acidic media.
• To overcome the challenge of hydrogen evolution reaction (HER) in proton-rich environments.

Main Methods:

• Utilized a hollow fiber silver penetration electrode with hierarchical micro/nanostructures.
• Employed a pH=1 solution of H₂SO₄ and KCl.
• Conducted density functional theory (DFT) calculations.

Main Results:

• Achieved 95% CO faradaic efficiency at a partial current density of 4.3 A/cm².
• Demonstrated stable electrolysis for 200 hours at 2 A/cm² with >85% single-pass CO₂ conversion.
• The hollow fiber design balanced CO₂ and H⁺/K⁺ supply, favoring CO₂ activation and *COOH intermediate formation.

Conclusions:

• The hollow fiber silver electrode effectively enables CO₂ electroreduction to CO in strong acids.
• Controllable CO₂ feeding via the electrode structure is key to suppressing HER and enhancing CO selectivity.
• This approach offers a promising pathway for carbon capture and utilization technologies.