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Comparative study of alcohols as sacrificial agents in H<inf>2</inf> production by heterogeneous photocatalysis using Pt/TiO<inf>2</inf> catalysts

Abstract:

In this work, a TiO2 photocatalyst synthesized using a sol-gel procedure (SG750) was Pt modified through photodeposition (SG750-2.1 wt%Pt) and tested for its efficiency in hydrogen production by heterogeneous photocatalysis in the presence of different alcohols as sacrificial agents. The tested alcohols were: methanol, ethanol, ethyleneglycol and glycerol. Production was continuously followed for 3.5 h. The concentration of each alcohol that resulted in the highest production was optimized and some of the degradation intermediates were identified and quantified in both gaseous and the remaining liquid phase at the end of the process. Optimum concentrations were found to be around 17.13 M for methanol and 7.34 M for ethanol, ethyleneglycol and glycerol. In terms of sacrificial agent used, hydrogen production was as follows: methanol > ethanol > ethyleneglycol > glycerol. The stability of the photoactivity of the catalyst was demonstrated through reuse cycles with 0.011 M of sacrificial agent and was also compared with that of commercial photocatalysts, in this case Aeroxide TiO2 P25 and Hombikat UV-100, with the same photodeposited Pt%.