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

Lee Siew Ling, University Technology Malaysia
Hadi Nur, University Technology Malaysia
Halimaton Hamdan, University Technology Malaysia

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 lmol) with selectivity of 65%. In contrast, no noticeable diol was produced when silica– titania aerogel and phosphate treated silica–titania sample were used.