THE EFFECT OF PROMOTERS ON THE PROPERTIES OF NI/AL2O3 CATALYSTS PREPARED BY SOLID STATE REACTION

Abstract

In this research, the effect of Mn and Cu promoters on the properties of Ni/Al2O3 catalysts prepared by the solid-state reaction of gibbsite, nickel nitrate, and promoters at 500°C for 3 h has been studied. The catalytic performances were tested in the carbon dioxide hydrogenation at 500°C and atmospheric pressure. It was found that the modified nickel catalysts with Mn exhibited the highest CO2 conversion in CO2 hydrogenation. The superior catalytic performance can be explained by higher Ni dispersion and a lower reduction temperature so that the reduction of NiO was easier. Further increasing the amounts of manganese and nickel on the catalysts also improved the catalytic activity. Comparing the non-modified Ni catalysts, the catalysts prepared by incipient wetness impregnation exhibited higher CO2 conversion than the ones prepared by the solid-state reaction. However, when modified with Mn the modified Ni catalysts obtained from the solid-state reaction exhibited higher CO2 conversion than the incipient wetness impregnation due to improved Ni dispersion and reducibility.