Improving TiO2 activity in photo-production of hydrogen from sugar industry wastewaters

A series of TiO2 photocatalysts dispersed on SiO2, modified with metals (Mn, Cr, V) or non-metals (N or S) or covered with Au nanoparticles were prepared by incipient wetness impregnation, impregnation with urea or thiourea, and deposition-precipitation, respectively. The photocatalysts where characterized by chemical analysis, X-ray diffraction (XRD), diffuse reflectance UV–Vis spectroscopy (DR-UV–Vis) and Fourier transform infrared spectroscopy (FTIR). The photocatalytic activity was checked in the photogeneration of hydrogen from sugar solutions. The nature of the modifying species was found to influence the photoactivity and N and S led to more effective catalysts than metals. This behavior was attributed to the fact the N and S are less effective in forming recombination centers compared with the metals.