XAFS Studies on the Metal Ion (Cu, Ag) Photocatalysts Prepared Within Zeolite Cavities Using an Ion-Exchange Method

摘要

Using a combination of in-situ XAFS, photoluminescence and diffuse reflectance measurements, the characterization of the coordination geometry of metal (Cu, Ag) ion photocataJysts 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 monomers, dimers and clusters, their relative concentration strongly depending of types of zeolites used. Within ZSM-5 and mordenite zeolites, most of the metal ions (Cu+, Ag+) were found to exist as isolated monomers with iow coordinate numbers (planar 3 or linear 2 coordinate geometry), in contrast to the case of the Y-zeolite having dimers and/or clusters.