Preparation of highly dispersed anchored vanadium oxides by photochemical vapor deposition method and their photocatalytic activity for isomerization of trans-2-butene

Highly dispersed anchored vanadium oxide catalysts have been first prepared by using facile reaction of the photochemically activated VOCl{sub 3} molecules with surface OH groups on Vycor glass. Anchored vanadium oxides prepared by photochemical method (photo-CVD) exhibit much higher yields in the phosphorescence with its long lifetimes (450 {mu}s). These anchored vanadium oxides exhibit a higher activity for the photocatalytic isomerization reactions of 2-butene, as compared with those obtained for the oxides prepared by conventional impregnation method. A good linear relationship between the yields of photocatalytic isomerization and the yields of phosphorescence from the charge-transfer excited triplet state of the surface vanadyl species in tetrahedral coordination is obtained, indicating that not only the surface vanadyl species play a significant role in the photocatalytic reaction on vanadium oxide catalysts, but also a photochemical vapor deposition method leads to the higher dispersion of vanadium than impregnation method.