Effect of niobia and alumina as support for Pt catalysts in the hydrogenolysis of glycerol

Catalysts of Pt/x%Nb2O5/Al2O3 (where x = 0, 1, 5, 10, 20 or 100) + Amberlyst 15 were evaluated through the reaction of glycerol hydrogenolysis in a batch system at 413 K and 50 bar of H-2, with the aim of producing 1,2-propanediol. The supports were characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR), scanning electron microscopy (SEM) and nitrogen adsorption (surface area - BET and pore size and volume - BJH). Niobia is present as islands on alumina surface, which reduces the interaction between these oxides and favors the creation of Bronsted acidic sites, so that the observed behavior is similar to pure niobia. All systems showed a high yield and selectivity for the production of 1,2-propanediol. The presence of niobia as a support leads to a highly active and selective catalyst for 1,2-propanediol production. The change in the behavior of the active metal can be related to the SMSI effect, inherent to systems containing niobia as support. (C) 2012 Elsevier B.V. All rights reserved.