A theoretical study of the effect of exchange cations in surface of ZSM-5 lamellar zeolites

The electronic properties of various cationic forms of MFI type lamellar zeolites were studied using DFT calculations and compared with their bulk counterparts. In this study, Na+ and H+ cations were considered for the effect of charge deficit compensation on the surface of lamellar zeolites. The results show that lamellar zeolites in different cationic forms exhibit two distinct band gap widths, whose values are lower than those of their bulk counterparts and arise from the surface atoms. Furthermore, the results suggest that the Na+ cation behaves as a structure-directing agent on the surface, while H+ passivates the surface of the lamellar zeolites.