Modulating C ₂ Selectivity in CO ₂ Electroreduction through Molecular Surface Engineering of Copper Nanowires

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic reduction of carbon dioxide (CO2) to multicarbon products is vital for artificial photosynthesis.
• Copper electrodes are promising for CO2 reduction but struggle with selectivity towards ethylene.
• Surface engineering offers a strategy to enhance selectivity in CO2 electroreduction.

Purpose of the Study:

• To develop a hybrid electrode architecture for improved CO2 electroreduction selectivity.
• To investigate the effect of organic shell functionalization on ethylene production.
• To understand the molecular-level mechanisms governing catalytic selectivity.

Main Methods:

• Fabrication of core-shell electrodes using copper nanowires (CuNWs) coated with electro-reduced dipyridophenazine (dppz) derivatives.
• Tuning interfacial properties through rational molecular design of the organic shell.
• Electrochemical characterization, DFT calculations, and ex situ surface analysis.

Main Results:

• Hybrid electrodes with electron-withdrawing groups on the dppz shell significantly increased ethylene selectivity (nearly tenfold Faradaic efficiency).
• Hydrophilic functionalities on the shell favored hydrogen production and suppressed C1/C2 products.
• DFT calculations elucidated the role of substituents in altering local electric fields and water binding.
• Polymeric coating stabilized the copper surface and provided insights into CuNW structural changes.

Conclusions:

• Modular hybrid electrode architecture effectively decouples catalyst selectivity from intrinsic metal properties.
• Molecular design of organic shells provides a powerful tool for controlling CO2 electroreduction pathways.
• This approach offers a scalable and promising route for efficient carbon conversion technologies.