Selective C₂ Electroproduction via Back Bonding in Asymmetric Copper-Copper Motifs

Area of Science:

• Catalysis
• Materials Science
• Electrochemistry

Background:

• Carbon dioxide reduction reaction (CO₂RR) is crucial for mitigating carbon emissions but faces challenges in converting C₁ intermediates to C₂ products.
• Copper catalysts show promise for CO₂RR, yet symmetrical charge distribution causes repulsive forces between adsorbed C₁ species, hindering C-C coupling.
• Overcoming these limitations is key to advancing CO₂RR efficiency and selectivity for valuable products.

Purpose of the Study:

• To engineer asymmetric copper-copper (Cu_F-Cu_N) motifs on a F-Cu₃N substrate.
• To investigate the distinct adsorption behaviors and electronic properties of these asymmetric motifs.
• To enhance the selectivity and efficiency of the carbon dioxide reduction reaction towards two-carbon products.

Main Methods:

• In situ isostructural substitution method to construct asymmetric Cu_F-Cu_N motifs on F-Cu₃N.
• Analysis of electronic structure, including orbital hybridization and electron delocalization, of the asymmetric motifs.
• Electrochemical evaluation of CO₂RR performance, focusing on C₂ selectivity and partial current density.

Main Results:

• Asymmetric Cu_F-Cu_N motifs were successfully synthesized, exhibiting distinct electronic properties compared to symmetric copper sites.
• Implanted fluorine (F) reduced Cu_N-N hybridization and introduced delocalized unpaired electrons in Cu_F, enabling unique bonding with *CHO intermediates.
• The asymmetric motifs facilitated C-C coupling by diminishing electrostatic repulsion between adsorbed *CHO, leading to high C₂ selectivity (81.5%) and a C₂/C₁ selectivity ratio of 10.47.

Conclusions:

• Asymmetric Cu_F-Cu_N motifs effectively promote C-C coupling in CO₂RR by manipulating atomic interactions and reducing electrostatic repulsion.
• This work demonstrates a novel strategy for designing advanced catalysts for efficient CO₂ conversion to valuable C₂ products.
• The findings offer a pathway for significant advancements in materials science for catalytic applications.