XAFS STUDIES ON THE METAL-ION (CU, AG) PHOTOCATALYSTS PREPARED WITHINZEOLITE CAVITIES USING AN ION-EXCHANGE METHOD

Using a combination of in-situ XAFS, photoluminescence and diffuse ref lectance measurements, the characterization of the coordination geomet ry of metal (Cu, Ag) ion photocatalysts prepared within zeolites by an ion-exchange method and thermovacuum treatment has been carried out. The metal ions within zeolites were found to exist as isolated monomer s, dimers and clusters, their relative concentration strongly dependin g of types of zeolites used. Within ZSM-5 and mordenite zeolites, most of die metal ions (Cu+, Ag+) were found to exist as isolated monomers with low coordinate numbers (planar 3 or linear 2 coordinate geometry ), in contrast to the case of the Y-zeolite having dimers and/or clust ers.