Glycerol hydrogenolysis to propanediols over supported Pd–Re catalysts

Abstract

Supported Pd–Re bi-component catalysts were prepared by an impregnation method and employed in a glycerol hydrogenolysis reaction. The addition of Re into a Pd catalyst increased the conversion of glycerol and the selectivities to propanediols. The catalysts were characterized by N₂ adsorption–desorption, XRD, CO chemisorption, TPR and NH₃-TPD techniques. The results showed that the addition of Re changed the reduction behaviors of the Pd and Re components, indicating that Pd and Re might have an interaction. Re could increase the ability of the catalysts for the activation of a C–O bond and further promote the activity of Pd in glycerol hydrogenolysis. At the same time, the addition of Re also increased the acidity of the Pd–Re catalysts. Pd–Re supported on acidic oxides showed a tendency of decreasing selectivities to 1,2-propanediol, while Pd–Re catalysts with basic oxides as supports could increase the conversion of glycerol, but maintain the selectivities to 1,2-propanediol.