Improved Hydrogen Production by Glycerol Photoreforming over Ag 2 O-TiO 2 Nanocomposite Mixed Oxide Synthesized by a Sol-gel Method

Hydrogen production from photocatalytic reforming of glycerol aqueous solutions has been investigated over Ag 2 O-TiO 2 nanocomposite mixed oxide catalysts with variable compositions (0.75-6.75 wt.%Ag 2 O) 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.0.72-2.82 wt.%) of Ag 2 O mixing could reduce TiO 2 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 TiO 2 sample, which indicates a great potential in improving the photocatalytic activities. The results of photocatalytic performance showed that H 2 -production activity and the reaction rate of TiO 2 were significantly enhanced by mixing Ag 2 O, and the effect of Ag 2 O mixing amount for H 2 production was discussed. The reaction rate could be increased by increasing the initial glycerol concentration which fitted a typical Langmuirian catalytic behavior.