Infrared spectroscopic study of the interactions of cations in zeolites with simple molecular probes. Part 2.—Adsorption and polarization of molecular hydrogen on zeolites containing polyvalent cations

Abstract

Cationic forms of different zeolites have been studied by diffuse reflectance infrared spectroscopy using low-temperature adsorption of molecular hydrogen as a probe. The frequency of the stretching vibrations of the H—H bond was found to be strongly dependent on the charge of the cations. For alkaline-earth-metal forms of high-silica zeolites the frequency shifts correlated with the polarizing ability (e/r) of the cations. The influence of different factors (hydrolysis of cations and their localization) on hydrogen polarization is also discussed.