CO₂ Electroreduction on Silver Foams Modified by Ionic Liquids with Different Cation Side Chain Length.

Area of Science:

• Electrochemistry
• Materials Science

Background:

• Ionic liquids (ILs) can modify catalyst interfaces to tune electroreduction kinetics.
• Silver (Ag) is a known catalyst for CO2 electroreduction.

Purpose of the Study:

• To investigate the effect of immobilized hydrophobic imidazolium-based ILs on Ag foam catalysts for CO2 electroreduction.
• To understand how IL properties, specifically N-alkyl chain length, influence CO2 reduction selectivity and rates.

Main Methods:

• Immobilization of hydrophobic imidazolium-based ILs on Ag foams using the "solid catalyst with ionic liquid layer" (SCILL) method.
• Electrochemical evaluation of the derived electrocatalysts for CO2 reduction.

Main Results:

• The IL-modified Ag foam catalysts showed altered selectivity and CO production rates compared to unmodified Ag foam.
• CO production rate was optimized at moderate IL chain lengths and loadings.
• High IL loadings or long alkyl chains reduced catalyst accessibility and promoted hydrogen evolution.

Conclusions:

• Immobilized ILs can effectively tune the performance of Ag-based electrocatalysts for CO2 reduction.
• The N-alkyl chain length of the IL plays a critical role in optimizing CO2 electroreduction and selectivity.
• Catalyst interface modification by ILs influences local CO2 concentration and active site environment.