Theoretical study for CO2 methanation on nickel-based catalysts

Among the catalytic reactions of CO2, the Sabatier reaction, or CO2 methanation reaction, is a suitable process for the conversion of carbon dioxide from point sources, like industrial flue gas, before it enters the atmosphere. Methane obtained through hydrogenation can be used both as a fuel or converted in high value-added chemicals. In this work, we carried out a theoretical study on CO2 interactions with nickel catalysts, using a density functional theory. Catalysts were treated with a “cluster” approach, in order to better understand the specific sites of adsorption. We modelled pure nickel and nickel-gold alloy clusters, because it has been proven that the presence of gold in the catalyst not only raises the methanation rate but also improve resistance from sulphur poisoning. Among the sulphur compounds responsible for poisoning and deactivating the catalyst, H2S has been taken into account for the study of interactions with pure and alloy clusters.