Nickel carbonate, basic, decomposition

Many promoters have been used to improve the performance of Ni/Al203 catalysts. The effect of the basic oxides of Na, K, Mg, and Ca on Ni/Al203 was examined by a number of authors (178,203,211 -213). They found that these added oxides markedly decrease the carbon deposition. The kinetics results showed that the added metal oxides changed the reaction order in CH4 from negative to positive and that in C02 from positive to negative. This observation implies that the surface of a nickel catalyst incorporating basic metal oxides is abundant in adsorbed C02, whereas the surfaces devoid of these oxides are abundant in adsorbed CH4 (178). The coverage of nickel with C02 is most likely unfavorable to CH4 decomposition... 

The temperature required for the reduction of cobalt oxides to the metal appears to be somewhat higher than for the reduction of nickel oxide. The catalyst with a higher catalytic activity is obtained by reduction of cobalt hydroxide (or basic carbonate) than by reduction of the cobalt oxide obtained by calcination of cobalt nitrate, as compared in the decomposition of formic acid.91 Winans obtained good results by using a technical cobalt oxide activated by freshly calcined powdered calcium oxide in the hydrogenation of aniline at 280°C and an initial hydrogen pressure of 10 MPa (Section... 

Sulfur-free catalyst is generally obtained by treating nickel nitrate with alkali carbonate, hydroxide, or hydrogen carbonate. The alkali salts formed during the precipitation must be removed so far as possible from the product. The nickel hydroxide or basic carbonate is then reduced, without prior conversion into the oxide. Nickel oxide is usually prepared by decomposition of nickel acetate or nitrate. 

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