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 (TM620-690C) 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 (Edes240 kJ mol-1, A1011 s-1).