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Calorimetric study of room temperature adsorption of N2O and CO on Cu(II)-exchanged ZSM5 zeolites |
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| Authors: | Vesna Raki Vera Dondur Spasenka Gajinov Aline Auroux |
| Affiliation: | a Faculty of Agriculture, Nemanjina 6, 11080, Beograd-Zemun, Yugoslavia b Faculty of Physical Chemistry, University of Belgrade, Belgrade, Yugoslavia c Institute of General and Physical Chemistry, Studentski trg 12, 11000, Beograd, Serbia and Montenegro d Institut de Recherches sur la Catalyse, 2, Av. A. Einstein, 69626, Villeurbanne Cedex, France |
| Abstract: | Copper ion-exchanged ZSM5 zeolites have been prepared with different cooper loadings from under- to over-exchanged levels. The adsorptions of N2O and CO at 303 K have been studied using calorimetric method and infrared spectroscopy. The samples were additionally characterised by ammonia adsorption at 423 K. The active sites for both N2O and CO are Cu(I) ions, which were formed as a result of pre-treatment in vacuum at 673 K. Room temperature adsorption of nitrous oxide at low equilibrium pressures (up to 66.7 Pa) resulted in small amounts of chemisorbed N2O (<0.2 molecule per one Cu ion). Differential heats of N2O adsorption between 80 and 30 kJ/mol were obtained. Differential heats of CO adsorption between 140 and 40 kJ/mol were obtained. The obtained amounts of chemisorbed species in the investigated systems and the values of differential heats of both nitrous oxide and carbon monoxide demonstrate the dependence on the copper content. |
| Keywords: | Calorimetry ZSM5 N2O CO FTIR of N2O |
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