Copper Atom Pairs Stabilize *OCCO Dipole Toward Highly Selective CO₂ Electroreduction to C₂H₄

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Electrolytic reduction of carbon dioxide (CO2) to ethylene (C2H4) is highly desirable but hindered by slow C-C coupling kinetics, leading to low selectivity.
• Existing copper catalysts, including single-atom sites, struggle to efficiently promote the C-C coupling step required for C2H4 formation.

Purpose of the Study:

• To develop a novel copper-based catalyst that enhances the selectivity and efficiency of CO2 electroreduction to ethylene.
• To investigate the mechanism by which the catalyst structure facilitates C-C coupling and stabilizes key intermediates.

Main Methods:

• Synthesis of a copper-based polyhedron catalyst (Cu2) with precisely arranged bi-copper units.
• Electrochemical evaluation of the Cu2 catalyst for CO2 reduction, measuring Faradaic efficiency and current density.
• In situ characterization techniques and theoretical calculations to elucidate the catalytic mechanism.

Main Results:

• The Cu2 catalyst achieved a 51% Faradaic efficiency for C2H4 production at a high current density (469.4 mA cm-2).
• Cu2 demonstrated significantly higher turnover frequencies (520 h-1) compared to Cu nanoparticles (~9.42 h-1) and Cu single-atom catalysts (~0.87 h-1).
• In situ studies and calculations confirmed that the unique Cu2 structure stabilizes the *OCCO intermediate, promoting C-C coupling.

Conclusions:

• The developed copper polyhedron (Cu2) catalyst effectively promotes C-C coupling for selective CO2 electroreduction to ethylene.
• The atomically precise bi-Cu units and optimized electronic structure of Cu2 are crucial for stabilizing intermediates and enhancing catalytic performance.
• This work presents a promising strategy for designing advanced catalysts for efficient CO2 conversion into valuable chemicals.