σ-π dative bond stabilizing copper active site drives CO₂ electrocatalysis to hydrocarbon

Area of Science:

• Electrochemistry and Catalysis

Background:

• Copper catalysts are essential for electrochemical CO2 reduction (CO2RR) but suffer from structural instability during electrolysis, limiting efficiency.
• Reconstruction of copper sites hinders long-term performance in CO2RR applications.

Purpose of the Study:

• To stabilize copper sites for prolonged CO2RR by utilizing strong σ-π dative bonding with alkyne-based ligands.
• To tune the electronic structure of copper sites to enhance selectivity and efficiency in CO2RR.

Main Methods:

• Synthesis of a functionalized copper-alkyne polymer (OMe-PhCu) to stabilize copper sites.
• Electrochemical evaluation of OMe-PhCu for CO2RR in acidic electrolyte.
• In situ spectroscopy and density functional theory (DFT) calculations to investigate reaction mechanisms.

Main Results:

• The OMe-PhCu catalyst demonstrated enhanced selectivity for methane production with a Faradaic efficiency of 68.8% and a partial current density of 324.5 mA cm⁻².
• Stabilized copper sites (Cuδ+) and tuned electronic properties improved CO adsorption and lowered the energy barrier for CO2RR to methane.
• Developed Cuδ+/Cu0 catalytic interfaces showed enhanced electrosynthesis of multi-carbon products and ammonia.

Conclusions:

• Strong σ-π dative bonding effectively stabilizes copper sites, enabling robust and efficient CO2RR.
• This approach provides a pathway for designing stable catalysts for renewable energy conversion technologies.
• The developed synthetic strategy facilitates the creation of advanced catalytic interfaces for diverse electrosynthesis applications.