Effect of K2O on the catalytic performance of Ni catalysts supported on nanocrystalline Al2O3 in CO2 reforming of methane

Abstract

CO2 reforming of methane (CRM) over unpromoted and potassium promoted Ni/Al2O3 catalysts was studied. The catalysts were prepared by impregnation method and characterized by X-ray diffraction (XRD), N2 adsorption (BET), temperature programmed reduction (TPR), temperature programmed oxidation (TPO) and scanning electron microscope (SEM) techniques. The obtained results showed that addition of K2O to the Ni/Al2O3 catalyst increased surface area. Also addition of K2O to this catalyst increased activity and decreased the amount of deposited carbon due to enhance the basic properties of the catalysts and CO2 adsorption and prevent the Boudouard reaction. In addition, effect of Ni and potassium loadings were investigated in Ni/K2O-Al2O3 catalysts. It was observed that by increasing nickel content, the specific surface area decreased, but catalytic activity and coke formation increased. Also, catalytic tests showed that just a moderate amount of K could improve catalytic activity and decrease coke formation of Ni/K2O-Al2O3 catalyst in dry reforming of methane.