Influence of alkaline and alkaline-earth cocations on the performance of Ni/β-SiC catalysts in the methane tri-reforming reaction

摘要

The influence of alkaline (Na, K) and alkaline earth (Mg, Ca) cocations on the behaviour of Ni/β-SiC catalyst for the tri-reforming of methane has been evaluated in this work. The cocations were loaded by co-impregnation with Ni, using different cocation/Ni ratios. Catalysts were characterized by AAS, TPR, N2 adsorption, CO2-TPD and XRD after calcination, as well as by XRD and TPO after reaction. It was analyzed the effect of the cocations on the β-SiC oxidation rate, which was increased when Na or K were loaded. The presence of Mg led to a high catalytic performance and stability (with a lower coke formation) since it provoked a decrease of Ni particle size and an increase of both the interaction between nickel and promoter and the catalyst basicity. Catalysts with Ni:Mg molar ratios of 2/1 and 1/1 showed the best performance in terms of activity and stability and formation of coke. These catalysts were considered good candidates for the tri-reforming of methane.