Enhanced Acidic CO₂-to-C₂₊ Reduction via Ionic Liquid Layer Modification

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Acidic CO2 electroreduction (CO2RR) is crucial for carbon mitigation but faces challenges in C2+ product selectivity.
• Weak CO adsorption and competitive H* adsorption limit efficiency in acidic media.

Purpose of the Study:

• To develop an effective strategy for enhancing CO2RR in acidic media.
• To overcome limitations of CO adsorption and H* competition on Cu catalysts.

Main Methods:

• Density functional theory (DFT) calculations to predict catalyst behavior.
• Cation-anion modification of Cu surface using ionic liquid [PMIM][NTf2].
• Electrochemical performance testing, resistance tests, and ATR-IR spectroscopy.

Main Results:

• [PMIM][NTf2] modification strengthens CO adsorption via quasi-hydrogen bonding.
• The ionic liquid layer creates a hydrophobic environment, reducing H* coverage.
• Achieved high C2+ partial current density (~640 mA cm-2) with 80.1% faradaic efficiency and ~20 h durability.

Conclusions:

• Cation-anion modification is a viable strategy for enhancing acidic CO2RR.
• [PMIM][NTf2] modified Cu catalysts show significant improvements in C2+ production.
• This approach offers a promising pathway for efficient carbon utilization.