Nanoscale Copper-Tin Dioxide Interfaces for Efficient CO₂ Electroreduction to Formic Acid and Formate at High Rates

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Efficient and selective electrocatalysts are crucial for converting carbon dioxide (CO2) into valuable chemicals.
• Developing cost-effective and stable catalysts is essential for industrial-scale CO2 utilization.

Purpose of the Study:

• To develop highly selective and stable copper-tin (CuSn) electrocatalysts for CO2 reduction.
• To investigate the effect of Cu-to-Sn atomic ratios on catalyst performance.
• To evaluate catalyst efficiency in both alkaline and acidic electrolytes.

Main Methods:

• A one-pot microwave-assisted solvothermal method was employed to synthesize CuSn catalysts.
• Catalyst composition was varied by adjusting Cu-to-Sn atomic ratios.
• Electrochemical CO2 reduction was performed in a flow cell setup using alkaline and acidic electrolytes.

Main Results:

• The optimal CuSn catalyst achieved over 90% Faradaic efficiency (FE) for formate (HCOO-) production in alkaline media at -200 mA cm-2.
• In acidic conditions (pH 3), the catalyst produced formic acid (HCOOH) with 70% FE at the same current density.
• The catalyst demonstrated excellent long-term stability, maintaining high FE for formate over 20 hours in 1 M KOH.

Conclusions:

• Copper-tin (CuSn) catalysts exhibit high selectivity and stability for CO2 electroreduction to formate and formic acid.
• The catalyst's performance is tunable by adjusting the Cu-to-Sn atomic ratio.
• These findings highlight the potential of low-cost CuSn catalysts for industrial CO2 conversion applications.