A spectroscopic study of the nature and accessibility of protonic and cationic sites in H- and partially exchanged Cu- and Co-MFI zeolites

Abstract

A study of the nature and accessibility of internal and external protonic and cationic sites has been carried out on protonic and partially Co- or Cu-exchanged ZSM5zeolite samples through UV-Vis and FT-IR spectroscopies. The samples were prepared by ionic exchange. o-toluonitrile has been chosen as a probe for the external surface of the zeolites. The existence of Cu2+ and Co2+ sites at positions different from those exchanging the active protons of the zeolites is emphasized.