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 (CORR) on Cu-based catalysts is still unclear. Herein, a Kinetic Monte Carlo (KMC) model that tracks the evolution of the CORR on the Cu (111)/(100) surface is developed. Using the Density Functional Theory calculated energetics of 178 elementary reactions in CORR toward C-C multispecies production, the KMC model predicted CORR 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 C species CH, 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 CH and CHCHOH production with CO* symmetric coupling step as RDS. This KMC model provides important insights into the CORR dynamics on Cu catalysts.