Improved Hydrogen Production by Glycerol Photoreforming over Ag2O-TiO2 Nanocomposite Mixed Oxide Synthesized by a Sol-gel Method

摘要

Hydrogen production from photocatalytic reforming of glycerol aqueous solutions has been investigated over Ag2O-TiO2 nanocomposite mixed oxide catalysts with variable compositions (0.75-6.75wt.%Ag2O) synthesized by a sol-gel method. Their structural and morphologic characteristics were investigated by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) method etc. It was found that a certain amount (ca.0.72-2.82wt.%) of Ag2O mixing could reduce TiO2 anatase grain size and increases the specific surface area of the catalysts. From UV-vis spectroscopy analysis, all these synthesized catalysts have certain degrees of red-shift compared with bare TiO2 sample, which indicates a great potential in improving the photocatalytic activities. The results of photocatalytic performance showed that H2-production activity and the reaction rate of TiO2 were significantly enhanced by mixing Ag2O, and the effect of Ag2O mixing amount for H2 production was discussed. The reaction rate could be increased by increasing the initial glycerol concentration which fitted a typical Langmuirian catalytic behavior.