FTIR study of carbon monoxide adsorption on ion-exchanged X, Y and mordenite type zeolites

Abstract

In this work Fourier transform infrared (FTIR) study has been applied to study the adsorption of carbon monoxide on transition metal (Mn2+, Co2 Ni2+) ion-exchanged zeolites type Y, X and mordenites. The adsorption of CO at room temperature produces overlapping IR absorption bands in the 2120?2200 cm-1 region. The frequency of the band around 2200 cm-1 is found to be dependent not only on the charge-balancing transition metal cation but also on the framework composition. The frequencies of the band near 1600 cm-1 was found to be dependent on the Si/Al ratio of the investigated zeolites.

Direct synthesis of phenol from benzene on iron-impregnated activated carbon catalysts

“…Carbon monoxide has a smaller molecular size, in addition to having a small dipole moment. It is also highly polarizable leading to its use as an adsorbent for studying surface acidity of many different materials [29,30,31].…”

Adsorption of sulfur dioxide on natural clinoptilolite chemically modified with salt solutions

“…The changes of the content and sites in the zeolite lattice, occupied by the cations, are especially important for some molecules which are specifically adsorped. It also allows the adsorption of molecules with different polarity and the application of the zeolite in catalytic processes [50].…”

“…they contain different quantities of exchangeable Na + , K + , Ca 2+ and Mg 2+ . The ion exchange with preliminary obtained monoion zeolite forms as sodium [2][3][4]7,9,11,16,19,20,50], potassium [9,15], calcium [5,9], hydrogen [35,40,42,57] or some other [3,6,9], is preferred in some cases to the direct application of natural zeolites. The advantage of using mono-ion forms is the possibility to avoid competitive effects [2].…”

Catalysts for selective propane oxidation in the presence of carbon monoxide: Mechanistic aspects

“…Other authors describe that such a blueshift comes from the decrease in the CAO bond length due to simple Coulombic field, induced by the positive point charge of the cation [56]. Other groups reported bands in this region as CO complexes at the active centers of zeolites [57,58]. Angell et al tested different cation exchanged X and Y-zeolites with the result, and that the heavier transition metal ions showed frequencies about 2200 cm À1 whereas the lighter alkaline earth ions showed frequencies below 2200 cm À1 [59].…”