The investigation of strong active sites of dealuminated Y-type zeolite by TPD of carbon monoxide

The active sites of hydrogen-exchanged Y zeolite (HY) and dealuminated (HDY) zeolites are investigated by TPD of carbon monoxide. Only the high temperature TPD spectra of CO (T(M)approximate to620-690degreesC) were observed, meaning that CO molecules interact with very strong acid sites. The amounts of CO bonded on these sites are small (less than 1 molecule per unit cell). The strong influence of dealumination on the coverage degree is found. The calculated values for kinetic parameters indicate chemisorption of CO in the investigated systems (E(des)approximate to240 kJ mol(-1), Aapproximate to10(11) s(-1)).8th European Symposium on Thermal Analysis and Calorimetry (ESTAC-8), Aug 25-29, 2002, Barcelona, Spai