EFFECTS OF NICKEL SOURCES ON THE STRUCTURE AND CATALYTIC ACTIVITY OF NICKEL SUPPORTED ON ALUMINA

The effects of nickel sources on the physical properties and catalytic activities of nickel-alumina catalysts were investigated. The catalysts were prepared by impregnation method using five kinds of nickel compounds (nickel nitrate, nickel formate, nickel acetate, nickel carbonate and nickel chloride) as nickel sources. The nickel particle size observed by pulse reaction technique and TEM showed that catalysts prepared from nickel carbonate and nickel formate gave large nickel crystallites, while thpse prepared from nickel nitrate and nickel acetate exhibited high dispersion. TPR measurement revealed a strong nickel-alumina interaction in the catalysts prepared from nickel formate and nickel carbonate. On the other hand, the catalysts prepared from nickel nitrate and nickel acetate showed a weak nickel-alumina interaction. The nickel particle size was correlated with the nickel-support interaction in these catalysts and they can be controlled by nickel starting materials. The activities of the catalysts for the hydrogenation of benzene and the dealkylation of toluene were investigated. The catalysts prepared by using nickel nitrate and nickel acetate showed high activities for both reactions while the catalysts prepared from nickel formate and nickel carbonate exhibited low activities. The nature of the active sites produced on the supports from the various nickel sources was discussed from the standpoint of the carrier effects. © 1990, The Chemical Society of Japan. All rights reserved.