Electrochemical CO2 reduction reaction (CO2RR) involves complicated processes spanning multiple scales, so understanding their effects on device performance is highly desired. Here, we present a multiscale strategy to predict the performance of an Ag-based H-type cell. The multiscale model consists of 1-D macro model, microkinetic model, and density functional theory (DFT) model. Free energy and barriers for CO2RR and hydrogen evolution reaction (HER) over Ag(111) surface are first obtained from the DFT model. These energy values are then used to determine the reaction rates for CO2RR and HER in the microkinetic model. These reaction rate values are finally imported into the macro model containing aqueous species. Using this multiscale model, we predicted the distribution of products and the partial current densities. We also described how factors such as CO2 coverage, the adsorption energy of H2O, and cathodic voltage affect electrochemical performance. Simulations under different CO2 pressures are being implemented, which is of great significance for understanding the mechanism of high-pressure electrochemical reduction of CO2. The investigation of electrochemical CO2RR presented in this work is helpful for the rational design of a high-performance CO2RR system.
Keywords CO2 reduction, electrochemical, multiscale simulation, density functional theory