Topologically Programmed Dual-Channel Covalent Organic Frameworks Decouple Gas and Ion Fluxes for Acidic CO₂...

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• High-rate CO2 electroreduction in acidic media faces challenges due to coupled gas/ion transport.
• Disordered catalyst layers lead to mass transport limitations and salt precipitation.

Purpose of the Study:

• To design a dual-channel covalent organic framework (COF) binder for structurally separating gas and ion transport.
• To improve CO2 electroreduction efficiency and stability in acidic electrolytes.

Main Methods:

• Fabrication of a Kagome-topology COF with distinct hydrophobic and ionic channels.
• Electrochemical testing of a Cu catalyst supported by the COF binder in acidic media.
• Mechanistic studies to understand interfacial phenomena and reaction pathways.

Main Results:

• The cationic COF (C-iCOF) binder facilitated unimpeded CO2 diffusion and electrolyte transport.
• Achieved 49.1% ethylene Faradaic efficiency and 42.7% single-pass carbon efficiency for C2+ products at 300 mA cm-2.
• Demonstrated pH buffering and suppression of carbonate formation.

Conclusions:

• Topological separation of transport pathways in COFs is effective for managing microenvironments in electrocatalysis.
• The C-iCOF binder enhances CO2 electroreduction by stabilizing intermediates and promoting C-C coupling.
• This approach offers a pathway to overcome limitations in industrial-scale electrochemical CO2 conversion.