Iodine-Modulated Silver Catalyst Reconstructed from a AgI Precatalyst for Efficient CO₂ Electroreduction to CO

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Silver (Ag) catalysts show promise for CO2-to-CO conversion but suffer from low activity and stability.
• Developing stable and active catalysts is crucial for efficient electrochemical CO2 reduction.

Purpose of the Study:

• To engineer a highly active and stable silver catalyst for selective CO2-to-CO conversion.
• To investigate the role of iodine modulation in enhancing silver catalyst performance.

Main Methods:

• Developed a halogen-retentive electrochemical reconstruction strategy using a silver iodide (AgI) precatalyst.
• Synthesized an iodine-modulated Ag catalyst (I-Ag).
• Characterized catalyst performance using electrochemical measurements and *in situ* FTIR spectroscopy.
• Employed density functional theory (DFT) calculations for mechanistic insights.

Main Results:

• The I-Ag catalyst achieved 97.6% CO Faradaic efficiency at -0.6 V vs RHE.
• Maintained over 90% selectivity for CO2-to-CO conversion for 12 hours.
• Demonstrated significantly enhanced activity and stability compared to commercial Ag catalysts.
• Identified electron-deficient Ag sites due to iodine moderation as key to improved performance.

Conclusions:

• The I-Ag catalyst offers a practical solution for efficient and durable CO2 electroreduction.
• Iodine modulation effectively enhances silver catalyst performance by stabilizing the *COOH intermediate.
• This work provides a new strategy for designing halogen-mediated catalysts for CO2 conversion.