Vsisble light-induced photocatalytic reactions on chromium containing mesoporous molecular sieves (Cr-HMS)

摘要

The photocatalytic reactivities of Cr-containing mesoporous molecular sieves (Cr-HMS) have been investigated. Cr-HMS involves tetrahedral chromium oxide (Cr-oxide) moieties which are highly dispersed and incorporated in the framework with terminal Cr=O bonds. In the presence of NO, Cr- HMS exhibited photocatalytic reactivity for the decomposition of NO into N_2, O_2, N_2O not only under UV light irradiation and but also visible light irradiation. Especially, under visible light irradiation, a higher selectivity for N_2 formation was observed. In the presence of propane and O_2, a complete oxidation proceeded under UV irradiation, mainly to produce CO_2. While partial oxidation proceeded under visible light irradiation to produce acetaldehyde with a high selectivity. Furthermore, the photoepoxidation of propene with O_2 and the photopoly-merization of ethylene proceeded efficiently under visible light irradiation on Cr-HMS. The charge transfer excited state of the tetrahedral Cr-oxide moieties and the large pores of the mesoporous molecular sieves play a significant role in the photocatalytic reactivities and selectivities