Abstract—Acid treatment using H₂SO₄, HCl and H₃PO₄ has been carried out in an attempt to improve catalytic performance of silica-titania aerogel. X-ray diffraction results showed the amorphous structure of the aerogels remained after the acid impregnation and calcinations steps. Hammert analysis revealed these acid modified silica-titania aerogels were superacids with pKa < -14.52. Different Ti species was observed in the samples upon the acid treatment. As compared to silica-titania aerogel, Lewis acidity increased remarkably in HCl treated sample without formation of any Brønsted acid site. Meanwhile, H2SO4 and H3PO4 treated samples possessed both Lewis and Brønsted acid sites. The catalytic performance of these samples was evaluated through a consecutive transformation of 1-octene to 1,2-octanediol through the formation of 1,2-epoxyoctane using aqueous hydrogen peroxide as oxidant.

Index Terms—Bifunctional catalyst, Brønsted acidity, oxidative site, silica-titania aerogel.

Siew Ling Lee, Catalytic Science and Technology Research Group, Nanotechnology Research Alliance, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia. Hadi Nur, Catalytic Science and Technology Research Group, Nanotechnology Research Alliance, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia. Pei Wen Koh, Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia,81310 UTM Skudai, Johor, Malaysia.(e-mail: sllee@ibnusina.utm.my) Jamilah Mohd Ekhsan, Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia,81310 UTM Skudai, Johor, Malaysia.(e-mail: sllee@ibnusina.utm.my) Soo Chien Wei, Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia.(e-mail: sllee@ibnusina.utm.my).

Cite:Siew Ling Lee, Hadi Nur, Pei Wen Koh, Jamilah Mohd Ekhsan, and Soo Chien Wei, "Synthesis and Characterization of Acid Modified Silica-Titania Aerogel as Oxidative-Acidic Bifunctional Catalyst," International Journal of Applied Physics and Mathematics vol. 1, no. 1, pp. 43-47, 2011.