Acid-Stable Cu Cluster Precatalysts Enable High Energy and Carbon Efficiency in CO₂ Electroreduction

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Electrochemical reduction of carbon dioxide (CO2) in acidic media offers high carbon utilization but faces challenges in selectivity for C2+ products and low overpotential.
• Oxide-derived copper (Cu) catalysts, effective in neutral/alkaline media, suffer from chemical instability in acidic conditions due to Cu ion leaching, deactivating C2+ active sites.

Purpose of the Study:

• To design and develop acid-stable copper cluster precatalysts for efficient electrochemical CO2 reduction in acidic media.
• To investigate the mechanism of catalyst stabilization and its impact on C2+ product selectivity and energy efficiency.

Main Methods:

• Design of acid-stable Cu cluster precatalysts.
• In situ reduction of precatalysts to active Cu nanoparticles in strong acid.
• Operando Raman and X-ray spectroscopy to analyze catalyst structure and active sites.
• Electrochemical measurements to determine Faradaic efficiency and overpotential for CO2 reduction.

Main Results:

• The designed Cu cluster precatalysts are stable in strong acid and reduce in situ to active Cu nanoparticles.
• Ligand bonding preserves a high density of undercoordinated Cu sites on the in situ formed Cu nanoparticles.
• Achieved a C2H4 Faradaic efficiency of 62% at a low overpotential.
• Demonstrated a 1.4-fold increase in energy efficiency compared to previous acidic CO2-to-C2+ electrocatalytic systems.

Conclusions:

• Chemical instability of oxide-derived Cu catalysts is a key limitation for CO2 electroreduction in acidic media.
• Acid-stable Cu cluster precatalysts effectively overcome Cu ion leaching and catalyst deactivation.
• The developed system offers a promising pathway for efficient and selective electrochemical conversion of CO2 to C2+ products in acidic environments.