Delocalization State-Stabilized Zn^δ+ Active Sites for Highly Selective and Durable CO₂ Electroreduction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Zinc-based materials are cost-effective catalysts for CO2 electroreduction to CO, but suffer from low selectivity and stability.
• Undercoordinated Zn (Znδ+) sites are effective for CO production, but tend to reduce under operating conditions, decreasing efficiency.

Purpose of the Study:

• To develop a highly selective and durable Zn-based electrocatalyst for CO2 reduction.
• To investigate the mechanism behind the catalyst's stability and activity.

Main Methods:

• Synthesis of a Zn cyanamide (ZnNCN) catalyst.
• Electrochemical testing for CO2 reduction.
• Density functional theory (DFT) calculations.
• Operando spectroscopy analysis.

Main Results:

• The ZnNCN catalyst maintained Znδ+ sites under cathodic conditions, preventing self-reduction.
• Achieved a high CO Faradaic efficiency (FE) of 93.9%.
• Demonstrated remarkable stability with a lifespan of 96 hours.

Conclusions:

• ZnNCN is a highly selective and durable electrocatalyst for CO2-to-CO conversion.
• The catalyst's structure, featuring delocalized Zn d-electrons and a resonant cyanamide ligand, is key to its performance.
• This work provides insights into controlling dynamic active sites for improved electrocatalyst design.