Distinguishing the mechanism of electrochemical carboxylation in CO₂ eXpanded Electrolytes

We shed light on the mechanism and rate-determining steps of the electrochemical carboxylation of acetophenone as a function of CO₂ concentration by using a robust finite element analysis model that incorporates each reaction step. Specifically, we show that the first electrochemical reduction of acetophenone is followed by the homogeneous chemical addition of CO₂. The electrochemical reduction of the acetophenone-CO₂ adduct is more facile than that of acetophenone, resulting in an Electrochemical-Chemical-Electrochemical (ECE) reaction pathway that appears as a single voltammetric wave. These modeling results provide new fundamental insights into the complex microenvironment in CO₂-rich media that produces an optimum electrochemical carboxylation rate as a function of CO₂ pressure.