Keggin heteropolyacid supported on TiO2 used in gas-solid (photo)catalytic propene hydration and in liquid-solid photocatalytic glycerol dehydration

(Photo)catalytic propene hydration to 2-propanol and glycerol dehydration to acrolein were carried out by using Keggin heteropolyacids (HPAs) supported on TiO 2 . Binary materials have been prepared by impregnation of H 3 PW 12 O 40 , H 3 PMo 12 O 40 and H 4 SiW 12 O 40 , on TiO 2 Evonik P25. Moreover, a binary material consisting of H 4 SiW 12 O 40 and TiO 2 was prepared via a hydrothermal treatment and tested for the same reactions. All the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM) coupled with energy dispersive X-ray (EDX) measurements, diffuse reflectance spectroscopy (DRS), Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR). The supported Keggin HPA species played a key role both for the catalytic and for the photo-assisted catalytic reactions due to their strong acidity and ability to form strong oxidant species under UV irradiation.