Direct synthesis of vanadium incorporated three-dimensional KIT-6: A systematic study in the oxidation of cyclohexane

The direct synthesis of three-dimensional (3-D) cubic V-KIT-6 was prepared using a Pluronic P123 triblock copolymer as the structure directing agent and n-butanol as the co-surfactant. The material obtained therein showed a very high specific surface area ∼1000 m2/g with pore diameters that could be tuned within a narrow size distribution of 5.7–6.0 nm. After calcination, Raman and UV–vis analysis revealed the presence of V5+ species in a highly dispersed state with much less crystalline V2O5 formation. 51V-NMR analysis showed that the vanadium species interacted directly with the silica framework in an almost symmetrical tetrahedral environment. NH3-TPD analysis for V-KIT-6 showed a wide distribution of acid sites at temperatures ranging from 200 to 800 °C. The calcined V-KIT-6 materials showed excellent catalytic activity in the direct oxidation of cyclohexane using dilute aqueous H2O2 as the oxidant.