Base-free glycerol oxidation over N-TiO2 supported Au-Pt catalysts

N-Doped TiO2 materials were used as support for the bimetallic gold-platinum nanoparticles catalysts. Via the sol immobilization technique, the metal particle dimension varied during the immobilization on the different supports. The prepared TiO2 samples were characterized by X-ray diffraction (XRD), N-2 physisorption (BET) and X-ray photoelectron spectroscopy (XPS), while the AuPt-TiO2 catalysts were characterized by transmission electron microscopy (TEM). The oxidation of glycerol by molecular oxygen in the aqueous phase over AuPt/N-TiO2 was investigated in a continuous upflow batch reactor under base-free conditions. The difference in the catalyst activities could be ascribed to the different support. The results revealed that N-doped TiO2 based catalyst support showed a higher activity in the oxidation of glycerol compared to the unfunctionalized one. The highest conversion (92% after 6 h) and the highest selectivity to glyceric acid (79.9%) were achieved using AuPt on TiO2 prepared with chitosan.