engleski

Influence of Framework n (Si)/n (Al) Ratio on the Nature of Cu Species in Cu-ZSM-5 for NH3-SCR-DeNOx

Nanosized Cu-containing ZSM-5 catalysts with different n(Si)/n(Al) ratio of 20.4-54.7 were prepared by ion-exchange. The physico- chemical characterization clearly shows that the molar ratio of framework T atoms influences the nature and distribution of copper species. According to DR UV-Vis, TPR-H2, EPR, or FT-IR spectroscopy analyses, the amount of aggregated copper species increases with increasing the framework n(Si)/n(Al) ratio. Thus, the activity of the Cu-containing ZSM-5 with n(Si)/n(Al) ratio of 50.9- 54.7 in the selective catalytic NO reduction with NH3 (NH3-SCR- DeNOx) significantly decreases compared to the other materials (n(Si)/n(Al) ratio of 20.4-21.2). The reaction mechanism has been discussed in light of the results of 2D COS (two-dimensional correlation spectroscopy) analysis of IR spectra and catalytic properties of the zeolites. The results make evident that enhanced activity of Cucontaining ZSM-5 in NH3-SCR-DeNOx is correlated with the formation of different NOx- under the experimental conditions.

ZSM-5 ; copper species ; NH3-SCR ; 2D COS analysis

nije evidentirano