Glycerol as an excellent hydrogen and electron source for photocatalytic hydrogenation of nitrobenzene in water

The development of a new method for effective utilization of glycerol dissolved in water is needed. In this study, glycerol was used not as an energy source and a starting compound but as an electron and hydrogen source for photocatalytic hydrogenation of nitrobenzene in an aqueous suspension of TiO2 under various conditions. The function of glycerol as an electron and hydrogen source was compared with that of other C3-alcohols and glycols. The results showed that glycerol works most efficiently as an electron and hydrogen source and that electrons extracted from glycerol are directly used for the hydrogenation without formation of other products such as H2. The photocatalytic hydrogenation was also examined under solar light with and without stirring. Important factors for the electron and hydrogen source in the photocatalytic reaction in an aqueous medium are discussed on the basis of the results.