Voltage-Dependent Electrochemical Carbon Dioxide Reduction Mechanism Unveiled by Kinetic Monte Carlo Simulation

The voltage-dependent dynamic evolution of the electrocatalytic carbon dioxide reduction reaction (CO2RR) on Cu-based catalysts is still unclear. Herein, a Kinetic Monte Carlo (KMC) model that tracks the evolution of the CO2RR on the Cu (111)/(100) surface is developed. Using the Density Functional Theory calculated energetics of 178 elementary reactions in CO2RR toward C1–C2 multispecies production, the KMC model predicted CO2RR linear sweep voltammetry and potential-dependent product distribution that agree well with experimental observations. Degree of rate control analysis reveals that, on Cu (111), the primary hydrocarbon product is C1 species CH4, and as the working potential increases, its rate-determining step (RDS) changes from CO hydrogenation toward the CHO* formation step into the COH* formation step. The Cu (100) surface is more active toward C2H4 and CH3CH2OH production with CO* symmetric coupling step as RDS. This KMC model provides important insights into the CO2RR dynamics on Cu catalysts.