Adaptive kinetic Monte Carlo simulation of methanol decomposition on Cu(100)

摘要

The adaptive kinetic Monte Carlo method was used to calculate the decomposition dynamics of a methanol molecule on Cu(100) at room temperature over a time scale of minutes. Mechanisms of reaction were found using minimum mode following saddle point searches based on forces and energies from density functional theory. Rates of reaction were calculated with harmonic transition state theory. The dynamics followed a pathway from CH_3OH, CH_3O, CH_2O, HCO, and finally to CO. Our calculations confirm that methanol decomposition starts with breaking the O–H bond followed by breaking C–H bonds in the dehydrogenated intermediates until CO is produced. The bridge site on the Cu(100) surface is the active site for scissoring chemical bonds. Reaction intermediates are mobile on the surface which allows them to find this active reaction site. This study illustrates how the adaptive kinetic Monte Carlo method can model the dynamics of surface chemistry from first principles.