Lateral interactions effect in the kinetic Monte Carlo study of the CO2 hydrogenation reaction on Ni(111)

Abstract

Several studies on the CO2 hydrogenation reaction have been carried out in recent years. These aimed to find a way to transform the CO2 molecule into CH4, in order to reduce emissions of the dioxide into the atmosphere by creating an energetic cycle, where the residue of a combustion is transformed into a new possible fuel. In this reaction, a total of 86 elementary processes are found, which include a total of 25 different species. These different processes create a competitiveness between them, which ends up leading to the formation of CO as the main product of this reaction. In this study, simulations of this reaction catalyzed on the Ni (111) surface have been carried out by means of the kinetic Monte Carlo method, using the Zacros program in its version 3.01. Thanks to this, it has been possible to observe the complete path carried out by these reactions under different levels of pressure and temperature. Moreover, a dependence of the processes taking place on the coverage of the H species on the catalytic surface, the species with the highest average coverage of all those recorded, was observed. This fact produces an interaction between any intermediate species of the reaction when it meets an H occupying an adjacent place on the catalytic surface. This effect is called lateral interaction, and has been the main object of study of this work. In addition, it has been observed how the reaction changes when the value of the lateral interactions is modified, creating a greater attraction or repulsivity between the neighboring species. With this, significant changes have been recorded in the energy barriers of the most important processes of this reaction, the dissociation of CO2 and CO, and the desorption of these two species