The hopping of protons in the anionic framework of H-ZSM5 having various SiO2/Al2O3 ratios was studied by means of complex impedance spectroscopy. It was found that the activation energy for hopping depended upon the spatial distance between the localization sites, as given by the SiO2/Al2O3 ratio, according to classical hopping transport theory.

Characteristics of Proton Hopping in Zeolite H-ZSM5. M.E.Franke, U.Simon: Physica Status Solidi B, 2000, 218[1], 287-90