Abstract: The relations of the adsorption properties and the behavior of catalytic decomposition of nitrogen monooxide over various copper ion-exchanged zeolites were studied by the means of in situ FTIR and temperature-programmed desorption (TPD). The results demonstrated that NO⁺, O^--Cu-NO and NO₃^- species were formed on the surface of the zeolites and desorbed at 350～400 K(denoted as α), 400～480 K(β) and 650～700 K(γ), respectively. It was found that the kinds and the amounts of the species were greatly changed with the zeolite structure and the copper ion exchange level, i. e . Cu-MFI, Cu-MOR and Cu-OFF/ERIgave α, β and γ peaks; Cu-FER gave α and β peaks; Cu -LTLand Cu-FAU only gave α peak. The amounts of desorption were increased linearly with the exchange level of copper on Cu-MFI. The O₂desorption peak appeared at the same temperature as that of the γ peak. In addition, by comparing the present results with the behavior of catalytic decomposition of NO, it is also found that NO₃^- species play a key role in the catalytic decomposition of NOand the formation of O₂over the zeolites.

Key words: Copper ion-exchanged zeolites, Nitrogen monooxide adsorption, Fourier transform infrared spectroscopy, Temperature-programmed desorption