Abstract:

HCl and KOH were used to modify bentonite(BEN). The Ni catalysts supported on acidified and alkalified bentonite had been prepared by aqueous impregnation. Methanation of carbon dioxide was used as a probe reaction to characterize the catalytic performance. The samples were characterized by BET, XRD, TPR and TPD. The results showed that a higher catalyst activity was achieved for Ni/alkali-BEN, although the alkali-BEN had lower surface area. CO2-TPD and H2-TPR study showed that Ni/alkali-BEN could absorb more carbon dioxide and be reduced easier. XRD and TPR analysis indicated that nickel oxide was the dominant species for both catalysts, which was easily reduced to metal nickel. The amount of nickel oxide presented in the Ni/alkali-BEN was higher than that of Ni/acid-BEN, which might account for the higher activity of Ni/alkali-BEN.

Key words: modified-bentonite, carbon dioxide hydrogenation, Methanation