Zeolite silver cluster stabilization

In contrast to zeolites X, Y and erionite, the amount of clusters formed in mor-denite was rather large, i.e., the cage structure of the latter proves to be ideal for silver cluster stabilization. In the electronic spectra of AgM upon reduction with hydrogen at different temperatures (Fig. 40), two intense bands at 320 and 285 nm dominate beside two weak bands at 410 and 235 nm as well as shoulders at 350,... 

B) Silver Atoms and Clusters in Faujasite Zeolites It has been shown recently by diifierent techniques that small, charged silver clusters can be formed and stabilized in the cavities of zeolites A, X and Y. Uytterhoeven et al (3b) have shown that... 

The use of y-irradiation and controlled thermal annealing to produce silver clusters in zeolites and related materials was reviewed by Michalik [114]. Unusual stability was attributed to Ag + clusters formed in this way in dehydrated zeolite rho, which were found to persist for months at room temperature and could be observed up to 100°C. In the zeoHte A analogue, AgH-SAPO-42 (LTA), dehydrated at 300 °C in flowing oxygen, clusters such as AgJ and Agf" were detected in very low yield, but, in the presence of methanol, Agl" species were... 

Intermediates in high-temperature processes have been stabilized at low temperature after y irradiation of metal oxides and zeolites. Important early examples were oxygen anions. O, 02 and O. Some of their reactions with small molecules were also elucidated by EPR. Metal cluster ions have also been produced by radiolysis and stabilized in zeolites. Examples include alkali metal cation clusters in faujasites and silver cation clusters in zeolite A and in silicoaluminophosphate molecular sieves. Detailed information was obtained from EPR studies about their structure, thermal stability and formation of adducts. 

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