Hydrogenation of CO_2 over Alkali Metal-modified Ni/Al_2O_3 Catalysts

摘要

A group of Ni and Ni, Li/Al_2O_3 catalysts were prepared using impregnation and controlled surface reaction methods. The various steps in the preparation were characterised by IR spectroscopy. The catalysts were reduced under the same conditions, while fixed conditions were also employed for the subsequent reactions in order to effect a better comparison. The total and metal surface areas, the degree of nickel reduction and the activity of the catalysts towards CO_2 methanation were all measured in order to compare the effect of preparation method on the structural properties as well as on the catalyst activity and selectivity. Nickel catalysts modified with lithium, either by controlled surface reaction or double impregnation utilising H_2Li_2EDTA, exhibited a higher activity in CO_2 methanation than any other catalyst samples investigated.