Production of hydrogen by glycerol photoreforming using binary nitrogen-metal-promoted N-M-TiO(2) photocatalysts.

The need for renewable energy focuses attention on hydrogen obtained by using sustainable and green methods. The sustainable compound glycerol can be used for hydrogen production by heterogeneous photocatalysis. A novel approach involves the promotion of the TiO2 photocatalyst with a binary combination of nitrogen and transition metal. We report the synthesis and spectroscopic characterization of the new N-M-TiO2 photocatalysts (M=none, Cr, Co, Ni, Cu), and the photocatalytic reforming of glycerol to hydrogen under ambient conditions and near-UV or visible light versus benchmark P25 TiO2 . In units of activity μmol m(-2)  h(-1) , N-Ni-TiO2 is five-fold more active than P25, and N-Cu-TiO2 is 44-fold more active. The photocatalytic activity of N-M-TiO2 increases from Cr to Co and Ni, whereas the photoluminescence decreases; the change in activity is due to the modulation of charge recombination.