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Photocatalytic isomerization of norbornadiene to quadricyclane over metal (V, Fe and Cr)-incorporated Ti–MCM-41

Paper ID Volume ID Publish Year Pages File Format Full-Text
47501 46473 2010 7 PDF Available
Title
Photocatalytic isomerization of norbornadiene to quadricyclane over metal (V, Fe and Cr)-incorporated Ti–MCM-41
Abstract

The photoisomerization of norbornadiene using M–Ti–MCM-41 (M = V, Fe and Cr) has been studied to develop an alternative for solar energy accumulation and high energy aerospace fuel synthesis. The photocatalysts were prepared via hydrothermal method and characterized by EDX, XRD, N2 adsorption–desorption, TEM, UV–vis, XPS and IR. With the same Si/M ratio in starting materials, the final concentration of V in the photocatalyst is significantly lower than that of Fe and Cr. V5+ and Fe3+ ions are highly dispersed in Si–O framework with tetrahedral coordination when the metal content is low, and the ordered structure is well retained. However, some species in higher coordination and polymerized environments present with increasing metal content, and the ordered structure becomes to collapse. Cr ions are difficult to get into the framework with various species like extraframework Cr6+ and bulk Cr2O3 formed, also the ordered structure is greatly destroyed. Under UV irradiation, the transition metal ions can improve the photoisomerization activity, with the order of V > Fe > Cr. The activities of V– and Fe–Ti–MCM-41 rise with the increase of Si/M ratio, whereas the performance of Cr–Ti–MCM-41 is irregular. The photocatalysts do not exhibit any activity under visible light, regardless of their absorption in visible-light region. The activity is closely related to the extent of dispersion and local structure of metal ions, about which an indirect excitation process of Ti–O species is suggested.

Keywords
Norbornadiene; Quadricyclane; Photocatalyst; M–Ti–MCM-41; Photoisomerization
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Photocatalytic isomerization of norbornadiene to quadricyclane over metal (V, Fe and Cr)-incorporated Ti–MCM-41
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 95, Issues 3–4, 6 April 2010, Pages 439–445
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
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