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

Abstract

(Photo)catalytic propylene hydration to 2-propanol and glycerol dehydration to acrolein reactions were carried out by using Keggin heteropolyacids (HPAs) supported on TiO2. Binary materials have been prepared by impregnation of H3PW12O40, H3PMo12O40 and H4SiW12O40, on TiO2 Evonik P25. Moreover, a binary material constituted by H4SiW12O40 and TiO2 was prepared via a hydrothermal treatment and tested for the same reaction. All the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM) and 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.