Keggin heteropolyacid H3PW12O40 supportedudon different oxides for catalytic and catalyticudphoto-assisted propene hydration

摘要

Catalytic and catalytic photo-assisted hydration of propene to form 2-propanol in gas–solid regime atudatmospheric pressure and 85 1C were carried out by using a heteropolyacid (POM) supported on differentudoxides. Binary materials were prepared by impregnation of H3PW12O40 on different commercial andudhome prepared supports (TiO2, SiO2, WO3, ZrO2, ZnO, Al2O3). Some of the composites were active bothudfor catalytic and catalytic photo-assisted reactions. The Keggin type POM was completely and partiallyuddegraded, when supported on ZnO and Al2O3, respectively, and these binary solids always resulted asudinactive for both catalytic and catalytic photo-assisted reactions. The supported Keggin POM speciesudplayed a key role both for the catalytic and the photo-assisted catalytic reactions, due to their strongudacidity and ability to form strong oxidant species under UV irradiation, respectively. The contemporaryudpresence of heat and UV light improved the activity of almost all POM supported materials. All materialsudwere characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM), diffuseudreflectance spectroscopy (DRS), determination of the conduction and valence band energy by photovoltageudmeasurements, Fourier transform infrared spectroscopy (FTIR), NH3-TPD experiments and timeudresolved microwave conductivity (TRMC).udIntroductionudPropene hydration to obtain 2-propanol is a reaction carriedudout at moderate temperatures (ca. 150–200 1C) and pressureud(2MPa) in the presence of an acid catalyst;1 however the realizationudof this reaction at ambient conditions is of great interest.udThe use