Surface properties and catalytic behaviors of WO3/SiO2 in selective oxidation of cyclopentene to glutaraldehyde

The structural transformation of WO3/SiO2 caused by thermal treatment was c haracterized by different techniques (X-ray diffraction (XRD), Raman and X- ray photoelectron spectroscopy (XPS)) and its effect on the catalytic perfo rmance in selective cyclopentene oxidation to glutaraldehyde was investigat ed. When calcined at ca. 673 K, the WO3 was present in the Keggin-type stru cture on the silica surface. With the further increase in calcination tempe rature, partial collapse occurred and the distorted structure coexisted wit h crystallite WO3. The correlation of the activity to structural feature wa s studied, which clearly demonstrated that the species resulted from the pa rtial decomposition of Keggin-type structure, rather than crystalline WO3 s pecies were involved in the catalysis. (C) 2000 Elsevier Science B.V. All r ights reserved.