In situ Formed Mesoporous Silver Nanowire Electrocatalysts for Efficient CO₂ Electrolysis

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical carbon dioxide (CO2) reduction faces challenges at high current densities, including electrolyte flooding and competing hydrogen evolution reaction (HER).
• Catalyst surface hydrophobicity is crucial for efficient CO2 reduction, but often compromised in conventional designs.
• Insufficient CO2 transport pathways limit reaction rates and selectivity.

Purpose of the Study:

• To develop novel electrocatalysts for efficient electrochemical CO2 reduction.
• To investigate the role of mesoporous architectures in regulating interfacial properties and CO2 mass transport.
• To establish a facile strategy for fabricating high-performance silver (Ag)-based CO2 reduction electrocatalysts.

Main Methods:

• A nanostructuring strategy involving sequential vapor-phase iodination and controlled electrochemical reduction of silver (Ag) was employed.
• In situ formation of organic-ligand-free mesoporous Ag nanowires (Ag NWs) was achieved.
• The influence of reduction rate on catalyst morphology (nanowires vs. nanodendrites) was studied.

Main Results:

• The mesoporous Ag NWs exhibited a morphology-driven partial-wetting state, enhancing electrolyte accessibility and CO2 transport.
• Achieved a high CO Faradaic efficiency of 98.9% at -1.06 V vs. the reversible hydrogen electrode (RHE).
• Demonstrated stable performance for over 300 hours at 100 mA cm-2 with a low H2 Faradaic efficiency of 2.63% even at 400 mA cm-2.

Conclusions:

• Mesoporous surface architectures are critical for optimizing interfacial wetting and CO2 mass transport in electrocatalysts.
• The developed nanostructuring strategy provides a facile and broadly applicable route for designing high-performance Ag-based CO2 reduction catalysts.
• The in situ formed mesoporous Ag NWs offer a promising solution for efficient and stable electrochemical CO2 conversion.