PLATINUM IN ZEOLITES - FORMATION OF CLUST ERS, PLATINUM STATE, AND CATALYTIC ACTIVITY

A review on the study of properties of the platinum clusters in zeolit es. The main attention is paid to the conditions of preparation affect ing the valence state of platinum and size and location of platinum cl usters in zeolites. These factors, together with the electronegativity of zeolite matrix (varied by the presence of different alkaline catio ns and Si/Al ratio), control the course of catalytic reactions as it i s shown in several model examples. The reduction of nitrogen monoxide by carbon monoxide is discussed as a special case.