Adsorption of CO and desorption of CO2 interacting with Pt (111) surface: a combined density functional theory and Kinetic Monte Carlo simulation

Abstract

The adsorption of CO and desorption of CO2 interacting with the Pt (111) surface was investigated using Kinetic Monte Carlo (kMC) simulation. The processes involved an elementary oxidation/reduction reaction (ORR). In comparison with standard density functional theory (DFT), kMC can simulate systems at practical time scale since it is concerned with the elementary reactions of the CO and O2 molecules adsorbed in the surface of the Pt system. The DFT results provide reliable estimates for adsorption and desorption energy barriers. The standard Arrhenius' equation serves as a working model to define the temperature dependence of individual elementary reaction rates (k). By incorporating the proper k obtained from DFT calculations into the kMC simulations, the study was able to reproduce acceptable result in agreement with practical microscopic reaction step occurring in the exhaust of gasoline engines. Thus, the kMC provides useful insight in the involved ORR steps in the interaction of CO and O2 with Pt. The ORR is sensitive to O–O dissociation compared with CO adsorption