Complementary approach to the adsorption of CO and N <inf>2</inf> O on bimetallic ion exchanged ZMS-5 zeolite: Microcalorimetric and FTIR spectroscopy study

Abstract

Room temperature adsorption of CO and N 2 O using isothermal calorimetry and in situ FTIR spectroscopy on bimetallic and monometallic forms of Cu, Fe and Mn exchanged zeolite ZSM-5 was studied. The two complementary techniques allowed the assessment of the strengths of interactions as well as the identification of the cations active in adsorption. In bimetallic samples containing Cu, a synergistic effect was observed for CO adsorption, i.e higher strengths of adsorption were detected than for corresponding monometallic samples. Such an effect was not detected for N 2 O. Furthermore, FTIR measurements revealed that N 2 O adsorption was somewhat restricted for the cation which was introduced the first in bimetallic samples. These findings imply the importance of the order of cation introduction and the procedure of ion exchange process for the adsorptive properties of bimetallic ZSM-5 and, consequently, catalytic reactions where adsorption of N 2 O is an important reaction step.