Metal Clusters of Silver

The dehydration-reduction of Ag+ ions in the zeolite pores to form silver clusters may involve two steps. The first occurs at a temperature lower than 250 °C, and, in this process, the silver ions oxidize the water molecules and are themselves reduced the second step in the process is a nonaqueous reaction, involving the oxidation of framework oxygen ions, and the reaction Equation (9.4) is as follows  

Because in zeolites the silver clusters change their color when in contact with water, it has been suggested that these compounds may be used as water-vapor-sensing materials. Ozin et al. observed the vapor-pressure chromic, cathode-ray chromic, water chromic, photochromic, and thermochromic properties for silver-sodalite, and they proposed that these compounds hold promise for use as sensors.[30] In addition, the silver clusters in zeolites are also sensitive to other molecules, and therefore, they have great potential as chemical-sensing materials. 

5 Noble Metal (Platinum, Palladium, Rhodium, Ruthenium, Iridium, Osmium) Clusters 

Zeolite molecular sieves play an important role in catalysis reactions. The introduction of noble metals into zeolite pores to form bifunctional catalysts is of particular interest. To introduce noble metals into zeolites, first noble metal ions or cation complexes are 

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