Synthesis of novel core-shell structured WO3/TiO2 spheroids and its application in the catalytic oxidation of cyclopentene to glutaraldehyde by aqueous H2O2

Novel core-shell structured WO3/TiO2 spheroids were synthesized through a conventional incipient wetness impregnation method and systematically characterized by X-ray diffraction, N-2 sorption, scanning electron microscopy, transmission electron microscopy, laser Raman spectroscopy, thermogravimetric and differential thermal analysis, X-ray photoelectron spectroscopy, and NH3 temperature-programmed desorption. It was found that tungsten species are highly dispersed in the interlayer between the core and the shell layer of the TiO2 support and that there are interactions between the tungsten species and the TiO2 support that could provide abundant oxygen defect lattice. It is also found that the as-prepared WO3/TiO2 material is highly active as a catalyst for the selective oxidation of cyclopentene to glutaraldehyde with aqueous hydrogen peroxide as the green oxidant. Proper content and high dispersion of tungsten species, the interaction between the tungsten species and the support, as well as the medium strong acidity of the novel WO3/TiO2 catalyst all account for this material's high activity. (c) 2005 Elsevier Inc. All rights reserved.