Selective CO₂ Electroreduction to Ethylene and Multicarbon Alcohols via Electrolyte-Driven Nanostructuring.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Carbon dioxide electroreduction (CO2 RR) is crucial for renewable energy storage and emission reduction.
• Developing highly selective catalysts for multicarbon products (C2+) remains a significant challenge.

Purpose of the Study:

• To electrochemically synthesize nanostructured copper (Cu) catalysts for enhanced CO2 RR selectivity towards C2+ products.
• To investigate the role of electrolyte-driven nanostructuring in catalyst performance.

Main Methods:

• Electrochemical synthesis of Cu catalysts with specific anions.
• CO2 electroreduction experiments in aqueous KHCO3 solution.
• Operando X-ray absorption spectroscopy (XAS) and quasi in situ X-ray photoelectron spectroscopy (XPS).

Main Results:

• Nanostructured Cu catalysts, particularly iodine-modified ones, showed high selectivity for C2+ products (ethylene, multicarbon alcohols).
• The iodine-modified catalyst achieved 80% Faradaic efficiency and a partial geometric current density of ~31.2 mA cm-2 for C2+ products at -0.9 V vs. RHE.
• Characterization revealed roughened surface morphology, subsurface oxygen, Cu+ species, and adsorbed halides contributing to selectivity.

Conclusions:

• Electrolyte-driven nanostructuring is an effective strategy for creating highly selective CO2 RR catalysts.
• The unique surface and electronic properties of the nanostructured Cu catalysts are key to their enhanced C2+ production.
• This work offers a promising pathway for efficient CO2 conversion into valuable chemicals.