C₆₀ Fullerene as the Active Site for CO₂ Electroreduction

Area of Science:

• Electrochemistry
• Materials Science
• Computational Chemistry

Background:

• Fullerene (C60) is explored as a catalyst promoter, but its specific catalytic role beyond electron transfer in electrochemical reactions is unclear.
• Previous simulations suggested C60 is inert in CO2 reduction (CO2RR) due to weak interactions with COOH* intermediates.

Purpose of the Study:

• To investigate the catalytic mechanism of C60 in CO2RR under electrochemical conditions.
• To elucidate the role of C60 in stabilizing intermediates and enhancing catalytic activity.
• To reconcile theoretical predictions with experimental observations of C60-based catalysts.

Main Methods:

• Development of a pH-field coupled microkinetic model at the reversible hydrogen electrode (RHE) scale.
• Quantitative pH-dependent modeling of CO2RR.
• Comparison of model predictions with experimental CO2RR data.

Main Results:

• Demonstration that C60 functions as molecular active sites, facilitating CO2RR to CO via strong binding to COOH* intermediates.
• Identification of C60's unique structure as the cause for large dipole moment changes, stabilizing COOH* intermediates across various pH conditions.
• Validation of the model through detailed comparison with experimental CO2RR observations.

Conclusions:

• C60's catalytic activity in CO2RR is attributed to its ability to strongly bind COOH* intermediates, contrary to previous beliefs.
• The significant dipole moment changes induced by C60 adsorption on curved surfaces are crucial for pH-dependent binding strength and electrocatalytic performance.
• This study provides new insights into the design and understanding of C60-based electrocatalysts for CO2 conversion.