Modulating CO₂ Electrocatalytic Conversion to the Organics Pathway by the Catalytic Site Dimension

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical reduction of carbon dioxide (CO2) offers a sustainable pathway for producing valuable organic chemicals.
• Mitigating greenhouse gas emissions is a critical global challenge, driving research into CO2 utilization technologies.

Purpose of the Study:

• To investigate the effect of tin (Sn) active site dimensions on carbon dioxide electroreduction.
• To develop highly selective and efficient electrocatalysts for CO2 conversion into acetate, ethanol, and formate.

Main Methods:

• Synthesis of carbon-supported Sn electrocatalysts with varying tin sizes (single atom, clusters, nanocrystallites).
• Electrochemical characterization including Faradaic efficiency (FE) and onset potential measurements.
• Computational modeling and structural characterization to elucidate reaction mechanisms.
• Kinetic isotope effect studies to understand reaction pathways.

Main Results:

• Achieved high single-product Faradaic efficiencies for acetate (90% @ -0.6 V), ethanol (92% @ -0.4 V), and formate (91% @ -0.6 V).
• Demonstrated size-dependent catalytic performance, with optimal activity observed for specific tin active site dimensions.
• Elucidated the CO2 conversion mechanism using a combination of experimental and computational techniques.

Conclusions:

• Carbon-supported Sn electrocatalysts with controlled active site dimensions are highly effective for selective CO2 reduction.
• The study provides fundamental insights into the size-modulated mechanism of p-block element electrocatalysis for CO2 conversion.