Selective and Efficient CO₂ Electroreduction to Formate on Copper Electrodes Modified by Cationic Gemini Surfactants

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Carbon dioxide (CO2) electroreduction is a key strategy for sustainable energy and chemical production.
• Existing methods often struggle with low product selectivity and poor catalyst stability.
• Need for efficient modifiers to improve CO2 electroreduction performance.

Purpose of the Study:

• To investigate the use of cationic Gemini surfactants as modifiers for CO2 electroreduction.
• To enhance the selectivity, activity, and electrochemical stability of CO2 electroreduction catalysts.
• To explore the mechanism by which Gemini surfactants influence CO2 electroreduction.

Main Methods:

• Modification of copper (Cu) electrodes with cationic Gemini surfactants.
• Electrochemical testing of modified electrodes for CO2 reduction to formate.
• Utilizing commercial bismuth oxide (Bi2O3) nanosheets modified with Gemini surfactants in a flow cell.
• In-situ studies to elucidate the role of surfactant structure in catalysis.

Main Results:

• Gemini surfactant modification significantly improved formate selectivity, activity, and stability.
• Faradaic efficiency (FE) for formate reached up to 96% on modified Cu electrodes.
• Energy efficiency (EE) reached 71% on modified Cu electrodes.
• Modified Bi2O3 nanosheets achieved 91% FE for formate at a high current density of 510 mA cm⁻² in a flow cell.

Conclusions:

• Cationic Gemini surfactants are effective modifiers for boosting CO2 electroreduction to formate.
• The structure of Gemini surfactants, particularly quaternary ammonium cations and alkyl chains, is crucial for stabilizing intermediates and facilitating CO2 access.
• This work provides insights for designing novel organic modifiers for advanced CO2 electroreduction catalysts.