Selective oxidation of glycerol over titania supported AuPd bimetallic catalysts

Oxidation of glycerol to form various types of important short chain oxygenated derivatives became an important reaction to support biodiesel industries. In this study, a series of AuPd nanoparticles at different metal ratio which were 9:1 and 8:2 supported on titania (TiO₂) were successfully prepared, characterized and tested for its activity and selectivity in liquid phase oxidation reaction of glycerol. All the catalysts were prepared by deposition-precipitation method with decomposition of urea agents. AuxPdy/TiO₂ catalysts were characterized using XRD, TEM and XPS. The formation of alloy Au-Pd phase was ascertained by XRD and XPS analysis. TEM analyses have shown that the Au and Pd metal particles in the range of 10-30 nm in size were uniformly dispersed on the TiO₂ support with narrower size distribution. Higher catalytic activity observed for the catalysts was attributed to the presence of metallic Au0 and PdO phases together with the ‘synergistic’ effect of Au-Pd alloy. The highest selectivity to tartronic acid (54.6%) was obtained by using Au₉Pd1/TiO₂ catalyst after 8 h of reaction time at lower reaction temperature (50⁰C).