COMPARISON PLOTS AS A TOOL IN ADSORPTION STUDIES OF CATALYSTS AND CATALYST PRECURSORS

Some aspects of the structure of solids in which adsorption occurs on two different components have been studied using the method of comparison plots. As the samples under study were prepared by different methods (introducing the platinum dispersion into a faujasite matrix by ion-exchange followed by autoreduction, physical mixing or kneading two components with or without a binder) and consisted of very different components (zeolites, oxides) their structure types differed widely. Considering the complex nature of these materials it was necessary to choose a suitable reference isotherm for each individual catalyst or precursor with respect to the information which was to be obtained. With two-component materials it is advisable to use a model reference adsorption isotherm calculated on the assumption of additive adsorption on the individual components. On materials consisting of components of considerably different adsorption properties the adsorption on the dominating single component should be taken as the reference variable.