Characterization of Fe-oxide species prepared onto ZSM-5 zeolites and their role in the photocatalytic decomposition of N2O into N-2 and O-2

Investigations on the effect of the local structures on Fe-ZSM-5 zeolites b y means of ESR, UV-Vis absorption and XRD measurements have shown that Fe-Z SM-5 with low Si/Al ratios includes highly dispersed Fe-oxides with tetrahe dral and distorted tetrahedral coordinations, while the latter species coul d not be observed in Fe-ZSM-5 with high Si/Al ratios. Moreover, the photoca talytic decomposition of N2O into N-2 and O-2 was found to proceed on Fe-ZS M-5 having low Si/Al ratios with a good linearity against the UV-irradiatio n time and a good stoichiometry. It was also observed that the photocatalyt ic efficiency decreased when the Si/Al ratio was increased. These results c learly suggest that a highly dispersed distorted tetrahedrally coordinated Fe-oxide species plays a significant role in the photocatalytic decompositi on of N2O into N-2 and O-2.