Tetrameric silver clusters in rho zeolite stable above room temperature — ESR studies

Abstract

Cationic silver clusters formed in γ-irradiated Ag +-exchanged zeolite rho have been studied by electron spin resonance (ESR) spectroscopy. It was found that dehydrated Ag-rho zeolites show a remarkable tendency for stabilization of Ag 4 3+ clusters. In dehydrated samples tetrameric silver is stable for months at room temperature and is still observed at 100°C. It is postulated that Ag 4 3+ clusters are located in distorted octagonal prisms which appear to be very effective trapping sites. In hydrated rho zeolite framework distortions are removed and silver tetramers decay below room temperature.