| 초록 |
A multi-scale simulation framework encompassing DFT, kinetic monte carlo (KMC) and computational fluid dynamics (CFD) to calculate the potential-dependent trend of CO production rate on Ag surface was designed. Especially, parameter optimization was applied for the pre-exponential factors of electrochemical rate constants in order to better fit the simulated result of CO current density to experimental data. Furthermore, sensitivity analysis was conducted to quantitatively evaluate the impact of each reaction step on CO production rate and to determine the rate-limiting step for CO production over Ag surface as a function of potential. The calculation results reveal that different rate-limiting steps are involved at different potential regimes. At high overpotentials, CO desorption step is rate-limiting while the CO coverage converges close to 100% and current density is saturated. In contrast, at lower overpotential region, electrochemical hydrogenation steps act as a key rate-limiting factor. This work not only provides intuitive understandings into the changing trend of CO2 reduction current by potential, but also emphasizes the importance of controlling desorption step. |
