Preparation, Characterization and Photocatalytic Activity of TiO2 Impregnated with the Heteropolyacid H3PW12O40: Photo-assisted Degradation of 2-propanol in Gas-Solid Regime

Abstract

Both commercial and home prepared TiO2 samples impregnated with tungstophosphoric acid (H3PW12O40) were prepared and used for the photo-assisted degradation of 2-propanol in gas-solid regime. The characterization results evidenced a good coverage of the polyoxometalate (POM) onto the surface of both types of TiO2 samples along with a marginal effect of the presence of ethanol or HCl during the POM impregnation step on the specific surface area, porosity, morphology, crystallinity and acidity of the samples. Propene was the main intermediate product found in 2-propanol photocatalytic degradation by using the samples containing POM as the photocatalyst, whereas propanone was mainly obtained when the photocatalyst was bare TiO2. Acetaldehyde was also an intermediate product and its amount was always significantly smaller with respect to propanone and propene (when formed). Carbon dioxide and water were the ultimate oxidation products. The selectivity to propene has been attributed to the acidity of the POM supported samples.