Heterostructured Bi-Cu₂S nanocrystals for efficient CO₂ electroreduction to formate

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical CO₂ reduction (ECO₂RR) is a promising route for renewable energy storage and sustainable chemical production.
• Achieving high efficiency, low overpotential, and high current density simultaneously in ECO₂RR remains a significant challenge.

Purpose of the Study:

• To synthesize novel heterostructured Bi-Cu₂S nanocrystals for enhanced ECO₂RR.
• To investigate the catalytic performance and mechanism of the synthesized materials.

Main Methods:

• One-pot solution-phase synthesis of Bi-Cu₂S heterostructured nanocrystals.
• Electrochemical characterization to evaluate catalytic performance (Faradaic efficiency, overpotential, current density).
• Density Functional Theory (DFT) calculations to elucidate reaction mechanisms.

Main Results:

• The heterostructured Bi-Cu₂S nanocrystals exhibited significantly reduced overpotential (240 mV lower than Bi).
• Achieved near-unity Faradaic efficiency (>98%) for formate production.
• Demonstrated substantially higher partial current density for formate compared to pristine Bi and Cu₂S.

Conclusions:

• The epitaxial growth of Cu₂S on Bi creates beneficial interfacial sites for ECO₂RR.
• Electron transfer at the Bi-Cu₂S interface preferentially stabilizes the formate intermediate, enhancing catalytic activity.
• The developed heterostructure offers a promising pathway for efficient and sustainable CO₂ conversion.