C60 Fullerene as the Active Site for CO2 Electroreduction.

Fullerene (C60) was considered as a catalyst promoter in various electrochemical reactions, yet its catalytic role in enhancing catalytic performance beyond electron transfer remains a puzzle to chemists. Traditional simulations imply C60's inertness in CO2 reduction reaction (CO2RR) due to weak interaction with COOH* intermediates. Here, according to a pH-field coupled microkinetic model at reversible hydrogen electrode (RHE) scale, we demonstrate that C60 acts as molecular active sites to facilitate the CO2RR toward CO through a strong binding to COOH* in the electrochemical conditions. This binding is mainly due to the unique structure of C60 that induces large dipole moment changes to stabilize COOH* intermediates across different pH conditions. By detailed comparison of experimental CO2RR observations and quantitative pH-dependent modeling, this work provides new insights on C60-based catalysts, highlighting the large dipole moment change upon adsorption at curved surfaces should not be dismissed when analyzing the pH-dependent binding strength and electrocatalytic activity.