APPLICATION OF RADIOACTIVE INERT-GASES FOR THE INVESTIGATION OF HETEROGENEOUS CATALYSTS AND OTHER SOLIDS

The possible applications of the emanation method, when radioactive inert gases are used to label the surface under study, are considered. Examples are given of the application of the method to the study of the processes of catalyst preparation, solid phase transitions and for investigating the heterogeneous catalytic reaction of isopropanoldehydration (dehydrogenation) over alumina and titanium oxide based catalysts. It is shown that the method can be used to determine the solid phase transition features including phase transitions without heat effects and allows the temperature region of the transitions and their kinetic parameters and the range of activation energies to be established. The method can be used to investigate heterogeneous catalytic reactions directly in the course of catalysis in order to obtain information about the local interaction of the reagent with the catalytic surface, the region of the catalytic action and the changes in the type of catalytic sites and the route of reaction. Particularly valuable information can be obtained by combining the emanation method with other physico-chemical techniques, e.g. X-ray phase analysis, differential thermoanalysis, dilatometric analysis and thermogravimetric analysis.