Physical Properties and Bifunctional Catalytic Performance of Phosphate–Vanadium Impregnated Silica–Titania Aerogel

Abstract

The excellent catalytic performance of phosphate–vanadium impregnated silica–titania aerogel as a bifunctional oxidative and acidic catalyst was evaluated in consecutive transformation of 1-octene to 1,2-octanediol through formation of 1,2-epoxyoctane using aqueous H₂O₂. Phosphate group and vanadium were impregnated onto silica–titania aerogel via wet impregnation method at room temperature, followed by a high calcination temperature. Significant increase of hydrated, tetrahedrally coordinated Ti species was found in phosphate–vanadium impregnated silica–titania sample. Pyridine adsorption study revealed that the combination of phosphate group and vanadium is essential for generation of Brønsted acidic sites. Phosphate–vanadium impregnated silica–titania catalyst produced 1,2-octanediol (275 μmol) with selectivity of 65%. In contrast, no noticeable diol was produced when silica–titania aerogel and phosphate treated silica–titania sample were used.