Molecular-Fence Confinement Enabling Efficient Acidic CO₂ Electroreduction to Multi-carbon Products

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Acidic CO2 electroreduction (CO2ER) is crucial for carbon utilization but hindered by hydrogen evolution and low C2+ selectivity.
• Acid-induced destabilization of the *CO intermediate and adsorbed hydrogen are primary challenges.
• Controlling the catalyst-electrolyte interface is key to improving CO2ER.

Purpose of the Study:

• To develop a novel "molecular-fence" strategy for enhanced acidic CO2ER.
• To overcome limitations of hydrogen evolution reaction competition and poor C2+ selectivity.
• To create and sustain a localized alkaline microenvironment in acidic media.

Main Methods:

• Engineered atomically dispersed Lewis acid Zr sites on Cu to accelerate *CO formation.
• Anchored π-conjugated benzo-2,1,3-thiadiazole (BTD) molecules to form a physical fence.
• Utilized dual modification to confine *CO and OH- for C-C coupling.

Main Results:

• Achieved 57.0% Faradaic efficiency for ethylene (C2H4) and 74.9% for C2+ products at 600 mA cm-2.
• Reached 64.2% single-pass carbon efficiency for C2H4 and 79.9% for C2+.
• Maintained high C2H4 selectivity (>52.0%) across a wide current density range (400-700 mA cm-2).

Conclusions:

• The molecular-fence strategy effectively regulates interfacial microenvironments for efficient acidic CO2ER.
• This approach enables high selectivity and efficiency in challenging acidic media.
• The strategy offers a broadly applicable paradigm for CO2 electroreduction.