Energy-Efficient Dual Formate Electrosynthesis via Coupled Formaldehyde Oxidation and CO₂ Reduction at Ultra-Low Cell...

Area of Science:

• Electrochemistry
• Catalysis
• Sustainable Energy

Background:

• Electrochemical formate production via CO2 reduction is promising for carbon-neutral energy but limited by high energy demand from oxygen evolution.
• Alternative anodic reactions are crucial for improving energy efficiency and economic viability.

Purpose of the Study:

• To develop an efficient catalyst for anodic formaldehyde oxidation reaction (FOR) as an alternative to oxygen evolution.
• To investigate the synergistic effects of Copper (Cu) and Silver (Ag) in the Cu-Ag catalyst for FOR.
• To demonstrate a dual formate production system coupling FOR with CO2 reduction.

Main Methods:

• Synthesis and characterization of Cu-Ag catalysts.
• In situ Raman spectroscopy to study reaction mechanisms.
• Electrochemical analyses including onset potential and Faradaic efficiency measurements.
• Coupling the anodic FOR with cathodic CO2 reduction reaction (CO2RR) in an electrochemical cell.

Main Results:

• The optimal Cu3Ag7 catalyst showed superior FOR performance with an onset potential of -0.05 V vs. RHE.
• Faradaic efficiencies for formate (HCOO-) exceeded 90% over a wide potential range (0.1-0.5 V RHE).
• The FOR||CO2RR system achieved a high HCOO- yield rate of 0.39 mmol h-1 cm-2 at a low cell voltage of 0.5 V.
• Demonstrated dual-side HCOO- production, surpassing previous electrochemical systems.

Conclusions:

• Cu-Ag catalysts offer an efficient alternative anodic reaction for electrochemical formate production.
• The synergistic effect of Cu and Ag enhances catalyst performance for FOR.
• This study presents a versatile and energy-efficient strategy for sustainable electrochemical synthesis.