Tuning C-C Coupling and Selectivity in CO₂ Electrochemical Reduction Reaction via Pyramidal Dilute Sn-Cu Alloy

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical conversion of carbon dioxide (CO2) is vital for climate change mitigation and carbon neutrality.
• Selective production of higher-order hydrocarbons (C2+ products) from CO2 remains challenging due to kinetic and thermodynamic limitations.

Purpose of the Study:

• To synthesize and characterize a novel tin-copper (Sn-Cu) alloy electrocatalyst for enhanced CO2 electroreduction.
• To investigate the effects of alloying and nanostructural engineering on catalytic activity and selectivity towards valuable products like ethylene (C2H4).

Main Methods:

• Fabrication of pyramidal dilute Sn-Cu alloy electrocatalysts via electrodeposition onto titanium substrates.
• Electrochemical testing to evaluate catalytic activity, selectivity, and stability.
• Density Functional Theory (DFT) calculations to elucidate reaction mechanisms and electronic structure modifications.

Main Results:

• The Cu99Sn1 catalyst, featuring pyramidal nanostructures, demonstrated significantly enhanced activity and selectivity for ethylene production.
• Achieved a Faradaic efficiency of 37% for C2H4 at -0.8 V versus RHE with over 12 hours of operational stability.
• Synergistic effects of Sn alloying (stabilizing CO intermediates, suppressing HER) and unique nanopyramid morphology (high-index facets, edge sites, defects) were identified.

Conclusions:

• Atomic-level alloying and nanostructural engineering are powerful strategies for tailoring CO2 electroreduction catalysts.
• The developed Sn-Cu catalyst offers a promising route for efficient, selective, and sustainable carbon utilization.
• This work provides insights into optimizing catalysts for converting CO2 into value-added fuels.