Cobalt containing ZSM5 zeolites preparation, characterizationand structure simulation

The incorporation of Co into ZSM5 by direct synthesis, ion exchange and impregnation methods is described. The influence of the preparation method on the density of sites and the stoichiometry of the ion exchange reactions was investigated. On samples prepared by solid state ion exchange, two new Lewis acid sites were formed, while the incorporation of Co by liquid phase ion exchange, synthesis and impregnation resulted in the creation of only one new Lewis acid site. A complete exchange could only be achieved with a stoichiometry of Co⁺²/Al⁺³=1 by solid state ion exchange. Liquid phase ion exchange resulted in a maximum exchange of about 22% with a ratio of Co⁺²/Al⁺³=0.5.