Protecting Copper Oxidation State via Intermediate Confinement for Selective CO₂ Electroreduction to C₂₊ Fuels

Area of Science:

• Catalysis
• Renewable Energy Storage
• Carbon Dioxide Conversion

Background:

• Efficient catalytic conversion of carbon dioxide (CO2) to value-added products is crucial for renewable energy storage.
• A key challenge is the difficulty in forming carbon-carbon bonds for producing higher hydrocarbons (C2+ compounds).
• Copper (Cu+) is active for C2+ formation but susceptible to reduction to Cu0 under reaction conditions.

Purpose of the Study:

• To develop a catalyst that stabilizes active Cu+ species during CO2 reduction.
• To enhance the selectivity and efficiency of CO2 conversion to C2+ hydrocarbons.
• To overcome the limitations of C-C bond coupling in CO2 electroreduction.

Main Methods:

• Design and synthesis of multihollow cuprous oxide catalysts with nanocavities.
• Electrochemical CO2 reduction experiments.
• Operando Raman spectroscopy and X-ray absorption studies to analyze catalyst behavior.

Main Results:

• The nanocavity catalyst demonstrated a C2+ Faradaic efficiency of 75.2 ± 2.7%.
• Achieved a high C2+ partial current density of 267 ± 13 mA cm-2.
• Observed a C2+ to C1 product ratio of approximately 7.2, indicating enhanced selectivity.
• Experimental evidence confirmed the stabilization of Cu+ species within the nanocavities during CO2 reduction.

Conclusions:

• Nanocavity catalysts effectively stabilize Cu+ intermediates, promoting efficient C-C bond formation.
• The designed catalyst significantly improves selectivity towards C2+ products in CO2 electroreduction.
• This approach offers a promising strategy for high-density renewable energy storage and CO2 utilization.