Lewis-base ligand-reshaped interfacial hydrogen-bond network boosts CO₂ electrolysis

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Catalyst and electrolyte performance are crucial for CO2 electrolysis.
• Tailoring electrolyte composition and understanding interfacial functions remain challenging.

Purpose of the Study:

• To investigate ethylenediaminetetraacetic acid (EDTA) and its analogs as electrolyte additives for CO2 electrolysis.
• To reshape the catalyst-electrolyte interface and promote CO2 reduction to carbon-based products.

Main Methods:

• Utilized mechanistic studies to understand EDTA's role at the catalyst-electrolyte interface.
• Investigated the effect of EDTA on interfacial water structure and ion solvation.
• Employed various catalysts (Ag, Zn, Pd, Bi, Sn, Cu) in H-type and flow-type electrolysis cells.

Main Results:

• EDTA dynamically assembles at the interface, disrupting the water hydrogen-bond network and forming a gap layer.
• EDTA-modified K+ solvation promotes CO2 protonation to *COOH and suppresses *H2O dissociation to *H.
• Faradaic efficiency of CO increased from 57.0% to 90.0% with 5 mM EDTA on Ag nanoparticles at 500 mA cm-2.
• Enhanced selectivity for carbon products was observed across multiple catalysts.

Conclusions:

• EDTA and its analogs are effective electrolyte additives for CO2 electrolysis.
• Reshaping the catalyst-electrolyte interface via Lewis base ligands significantly improves performance.
• This approach offers a versatile strategy for enhancing carbon-based product selectivity in CO2 electroreduction.