A quantitative analysis is carried out for some simple models describing the possibility of a mechanical separation of metal particles using spacer grains present in a catalyst. The separation of the metal particles prevents their sintering, thus reducing deactivation of the catalyst during its operation. Relationships are determined between the loading of metal, relative catalytic activity and the chemical composition of the catalyst on the one hand and the ratio of the size of the metal particles to that of the spacer grains on the other. The results obtained are useful in planning the experiments concerning the preparation of metallic catalysts resistant to thermal deactivation.