Au/TiO 2 -CeO 2 Catalysts for Photocatalytic Water Splitting and VOCs Oxidation Reactions

摘要

Photocatalytic water splitting for H 2 production and photocatalytic oxidation of 2-propanol, an example of volatile organic compounds, were investigated over TiO 2 catalysts loaded with gold and/or ceria. In the water splitting reaction the presence of gold only slightly affected the performance of TiO 2 whereas the presence of CeO 2 had a more remarkable positive effect. In the 2-propanol oxidation Au/TiO 2 was the most active sample in terms of alcohol conversion whereas Au/TiO 2 -CeO 2 exhibited the highest CO 2 yield. On the basis of characterization experiments (X-Ray Diffraction (XRD), Energy Dispersive X-ray Analysis EDX, surface area measurements, Diffuse Reflectance Spectroscopy (DRS) and Raman spectroscopy), it was suggested that the interaction of Au with TiO 2 causes an increase in the charge separation between the photo-excited electron/hole pairs, leading to an enhanced photocatalytic activity (to acetone over Au/TiO 2 and to CO 2 over Au/TiO 2 -CeO 2 ), whereas the presence of ceria, acting as a hole trap, positively mainly affects the formation of hydrogen by water splitting.