Characterization and photocatalytic reactivities of Cr-HMS mesoporous molecular sieves

Investigations of the local structures and photocatalytic reactivity of Cr- containing mesoporous molecular sieves (Cr-HMS) have been carried out. Cr-H MS involves tetrahedrally coordinated Cr-oxide species which are highly dis persed and incorporated with terminal Cr = O groups in the framework of mol ecular sieves. On the other hand, the imp-Cr/HMS prepared by an impregnatio n method consists of both tetrahedrally and octahedrally coordinated Cr-oxi de species. The Cr-HMS exhibits much higher photocatalytic reactivity under UV irradiation for the isomerization of cis-2-butene than the imp-Cr/HMS a nd Cr-silicalite microporous catalysts. The charge transfer excited state o f the tetrahedrally coordinated Cr-oxide species plays a significant role i n the photocatalytic reaction.