Solvent Mediated Interfacial Microenvironment Design for High-Performance Electrochemical CO₂ Reduction to C₂₊...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical CO2 reduction (CO2RR) in membrane electrode assemblies (MEAs) is key for converting CO2 to multi-carbon (C2+) compounds.
• Catalyst layer (CL) microstructure, influenced by solvent environment, impacts gas transport, charge conduction, and proton supply.
• The CL microenvironment and solvent effects on C2+ selectivity are not well understood.

Purpose of the Study:

• To design a tailored interfacial structure using a solvent-mediated catalyst-ionomer-solvent microenvironment.
• To investigate the mechanism of solvent effects on C2+ selectivity in CO2RR.
• To optimize the catalyst layer for enhanced C2+ production.

Main Methods:

• Acetone surface promotion strategy for catalyst layer fabrication.
• Molecular dynamics (MD) simulations to study interfacial networks.
• In situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) for mechanistic insights.

Main Results:

• Acetone treatment promotes uniform ionomer coating, enhancing hydrophobicity and suppressing hydrogen evolution.
• Optimized interfacial network with balanced CO2 and H2O distribution achieved in acetone.
• Acetone-mediated interface favors CO2-to-C2+ conversion, leading to high C2+ faradaic efficiency (FE).

Conclusions:

• A solvent-mediated interfacial structure design is effective for enhancing CO2RR performance.
• Acetone surface promotion strategy optimizes the catalyst layer microenvironment for C2+ selectivity.
• The optimized Cu-based MEA achieved 80.27% C2+ FE at 400 mA cm-2.