Genesis of Highly Active Cobalt Sulfide Catalyst for Hydrogenation and Isomerization: Effect of the Calcination Temperature of Precursor Cobalt Oxide upon the Catalytic Properties of Cobalt Sulfide

Abstract It was found that the catalytic activities and selectivities of cobalt sulfide catalysts are significantly affected by the calcination temperature of precursor cobalt oxide for the hydrogenation of butadiene and the isomerization of 1-butene. When cobalt sulfide was prepared from cobalt oxide calcined at 1473–1573 K, the specific activities per surface area of the sulfide were enhanced by 30–40 times those of cobalt sulfide prepared from cobalt oxide calcined at a conventional temperature, 573–973 K. The reaction selectivities were also strongly modified by the calcination temperature of precursor oxide. It is suggested that two different types of active sites are formed on cobalt sulfide, depending on the calcination temperature of the precursor. On the basis of XPS, XRD, SEM, and NO adsorption techniques, it is concluded that the particle size of the precursor cobalt oxide and sulfiding conditions determine the surface sulfur content and hence the catalytic properties of the sulfide catalysts. The sulfidation mechanism of cobalt oxide and active site models are proposed.