Relationship between the Local Structures of Titanium Oxide Photocatalysts and Their Reactivities in the NO Decomposition

摘要

@@ The photocatalysts included titanium oxide were prepared by ion-exchange method and impregnating method, in which zeolites of different Si/Al ratios were used as supporters. Those photocatalysts by an ionexchange method in zeolite of low Si/Al ratio, exhibited high and unique photocatalytic reactivity for the direct decomposition of NO into N2, N2O and O2 at 275K. In situ photoluminescence, diffuse reflectance absorption,XAFS investigations indicated that the titanium oxide species are highly dispersed within the zeolite and exist in tetrahedral coordination when the titanium oxide species anchored in the zeolite of low Si/Al ratio. The charge transfer excited state of the highly dispersed titanium oxide species play a significant role in the decomposition of NO exhibrting a high selectivity for the formation of N2, while the catalysts involving the aggregated octahedrally coordinated titanium oxide species show a high selectivity to produce NiO, being similar to reactions on the powdered TiO2 catalysts.