Incorporation of AgI clusters into the cages of zeolites LTA and FAU observed by optical spectra and X-ray diffraction patterns

The loading of AgI into the cages of zeolites LTA and FAU was performed by vapor-phase adsorption. The successful incorporation of AgI clusters into the cages was confirmed by optical absorption spectra and X-ray powder diffraction patterns. Large blue shifts of the absorption edges were observed in the spectra of adsorbed AgI to both zeolites, compared with the lowest excited state of AgI in the bulk. The present observation of the shift implies that a strong quantum confinement in the photoexcited state of AgI occurs, which leads to the conclusion that AgI clusters have been formed in the cages. In the X-ray powder diffraction pattern of AgI-loaded LTA, superlattice reflection peaks are observed which cannot be assigned either to the reflection of LTA or the AgI in the bulk.