| Abstract
| - The effect of charge balancing cations on encapsulation of CO in the pores of Y-zeolite has been investigatedusing FTIR spectroscopy. The multiple vibrational bands in CO and CO2 stretching regions, originating fromthe clusters of these molecules and developed on exposure of CO on Na−Y, undergo an identical shift infrequency and relative intensity when Na+ are exchanged with group IIA cations. Thus, a constant blue shiftof ∼18, 12, and 6 cm-1 was observed in all the ν(CO) bands for the samples exchanged with Ca2+, Sr2+, andBa2+, respectively. The respective Δν(CO2) on Ca2+, Sr2+, and Ba2+ exchanged zeolite-Y were found to bearound +6, +2, and −2 cm-1. The observed frequencies of all the CO and CO2 vibrational bands and theirrespective Δν values with respect to gas-phase frequency are found to show a close relationship with theionic radius, pore volume, electrostatic potential (e/r), or the field strength (V/Å) associated with the exchangingcations. The data reveal that the characteristics of zeolitic pores play a more important role in encapsulationof CO molecules, rather than the direct bonding of CO at cation sites.
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