Comparison between different oxygen adsorption mechanisms for the catalytic oxidation of CO on a surface

TL;DR

This paper uses kinetic Monte Carlo simulations to compare different oxygen adsorption mechanisms in a modified ZGB model, aiming to eliminate the nonphysical continuous transition and analyze phase diagrams with CO desorption.

Contribution

It introduces and compares three oxygen adsorption mechanisms in the ZGB model, demonstrating how they remove the unphysical phase transition observed in the standard model.

Findings

The nonphysical continuous transition disappears with the new mechanisms.

Phase diagrams are significantly affected by the different oxygen adsorption rules.

Including CO desorption alters the phase behavior and stability regions.

Abstract

We study by kinetic Monte Carlo simulations the dynamic behavior of a Ziff-Gulari-Barshad (ZGB) model for the catalytic oxidation of CO on a surface. It is well known that the ZGB model presents a continuous transition between an oxygen poisoned state and a reactive state that it is not observed in nature. Based on some experimental results that indicate that the oxygen atoms move away from each other upon dissociation at the surface, we modify the standard ZGB model by changing the entrance mechanism of the oxygen molecule. We study three different ways in which the oxygen atoms can be adsorbed at the surface such that the nonphysical continuous phase transition disappears. We calculate the phase diagram for the three cases and study the effects of including a CO desorption mechanism.