FTIR spectroscopic studies of methane adsorption on sodium and cesium containing Y-zeolites

Methane adsorption on NaY and cesium containing Y-zeolites has been investigated by FTIR spectroscopy. The results indicate an adsorption-induced symmetry reduction of CH4 from Td to C3v. A splitting of the ν1 mode in NaY can be attributed to the interaction of CH4 with Na+ ions in the different zeolite sites. The location of Cs+ ions in different crystallographic positions cannot be resolved. In addition to CH4 complexes with alkali cations, an interaction with weakly basic framework oxygens could also be detected in NaY. In the Cs+-containing Y-zeolite, the corresponding ν1 mode seems to coincide with that of the Cs+…HCH3 complex.