The Effect of Preparation Method on Ni/Ce/Al Catalyst for High Temperature Water-Gas Shift Reaction

Abstract

High temperature water gas shift (HT-WGS) is an important catalytic process connected with reforming process in hydrogen production. Ni/CeO2-Al2O3 (or Al2O3) catalysts were studied in this work on the effect of catalyst preparation method toward the physicochemical properties and the HT-WGS activity. Ni/CeO2-Al2O3 were prepared by sol-gel and impregnation methods whereas Ni/Al2O3 was prepared by impregnation method. The catalyst samples were characterized by XRD, H2-TPR and H2-TPD techniques. The catalytic activities of HT-WGS catalysts was demonstrated at 550°C, GHSV of 2x105 mLh-1gcat-1and steam-to-CO ratio of 3. Nickel was detected as a nickel aluminate phase in the calcined catalyst. Ni strongly interacted with support in the calcined catalyst prepared by sol-gel method. The strong metal-support interaction can be resisted by preparing catalyst via impregnation and CeO2 can promote the H2O dissociation in HT-WGS mechanism. The highest metal dispersion, largest metal surface area and greatest HT-WGS activity were consequently achieved by Ni/CeO2-Al2O3 prepared from impregnation method.